TEXAS AGRICULTURAL EXPERIMENT STATION

R. D. LEWIS, Director
College Station, Texas

BULLETIN NO. 690 SEPTEMBER 1947

Vitamin A and Carotene
in Human Foods

G. S. FRAPS
Collaborating Chemist

 

AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS

GIBB GILCHRIST, President

J 4-947-3M-L1 80

Preface

_ Vitamin A is one of many vitamins which, together with "energy,

protein and mincrals,.must be present in sufficient amounts to pro-
 vide an adequate diet. Carotene is converted to vitamin A in the
 process of digestion; The vitamin A contents of livers, eggs, milk
 and butter depends upon the carotene or vitamin A content of the
‘E tilCl. '
t Carotene-s are mixtures. The carotenes of raw leafy vegetables
' averaged 76 percent beta-carotene, 10 percent neo-beta-carotene U
r and 1o percent neo-beta-carotene B. Beta-carotenes have higher values
(or vitamin A than other, carotenes. Carrots and pumpkins also con-
i tain alpha-carotene, and corn contains cryptoxanthin.

   
 
 
 
  
 
 
 
   
   
     
  
  

V gThe average digestibility of carotenes by rats is 44 percent with

greens and 32 percent with other vegetables. Carotene in vegetables
A [ed rats at a low level sufficient for maintenance and slight growth
. had an average vitamin A potency of g3 percent of carotene in oil;
lint fed at higher levels and the values measured by storage of vitamin
. A in the liver, carotene in vegetables averaged 32 percent of that of
p carotene in oil. Insuflicient carotene in the diet shortens the life of
i rats and the number and vigor of the young.

M The relative costs of vitamin A and carotene in different foods are
‘discussed, also the human requirements of vitamin A and carotene,
{and the balancing of human diets in carotene.

T; The many tables presented show the variations in vitamin A and
fifiiarotene in foods, the composition of carotenes, the digestibility and
‘ifytilization of carotenes, the carotene content of human foods, the
“tiumber of pounds of food which contains 5,000 units of vitamin A
 5,000 micrograms of carotene, and the cost of 5,000 micrograms
of carotene or 5,000 units of vitamin A in various foods in june 1947.

CONTENTS

 

Page A
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5g

Estimation of Vitamin A Potency and of Carotenes . . . . . . . . . . . . . . . . .. 6 

Variations in Vitamin A Content of Livers . . . . . . . . . . . . . . . . . . . . . . . .. 7 1

Variations in Butter, Milk and Cheese . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 -

Variations in Eggs» . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 ‘A

Variations in Y-ellow Corn Due to Heredity . . . . . . . . . . . . . . . . . . . . . . . . . . 13 a

Constituents of the Carotenes of Some Human Foods . . . . . . . . . . . . . .. 13

Beta-carotene Equivalent of Carotenes in Vegetables . . . . . . . . . . . . . . . . . 15 a

Elfect of Cooking, Canning and Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 16

Digestibility of Carotenes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 16
Utilization by Rats of Carotenes in Vegetables for Vitamin A Potency. . 17 
Efiect on Rats. of Insuflicient Carotene in the Diet . . . . . . . . I . . . . . . . . . 19 
Human Requirements for Vitamin A and Carotene . . . . . . . . . . . . . . . . . .. 20 -
Carotene in Texas Foods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 21 a
Vitamin A and Carotene per Pound of Edible Parts of Foods and of
Foods as Purchased . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 24

Relative Cost of Vitamin A Potency in Foods . . . . . . . . . . . . . . . . . . . . . . .. 26 '

Balancing the Diet in Vitamin A Potency . . . . . . . . . . . . . . . . . . . . . . . . .. 28 _

Acknowledgment . . . .' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .‘ . . . . . . . 30 

Summary . . . . . . . . . .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

Bibliography . . . . . . . . . . . . . . . .' . . .~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

.__ri_/___. .._.__...al._..a_am._u_..ima.u._u..re..__i. 1 .

BULLETIN NO. 690 SEPTEMBER 1947

Vitamin A and Carotene
in Human Foods

G. S. FRAPS‘, Collaborating Chemist*

It is now well recognized that an adequate human diet must con-
tain carbohydrates, fats, protein, minerals and vitamins in certain

. amounts (56). The carbohydrates, fats and proteins supply energy

(calories), which is usually expressed in terms of metabolizable en-
ergy, although it may also be expressed as productive energy (14).
The energy is used for carrying 0n vital activities, keeping the
body warm, in materials, for growth, for work and gain in weight.
In addition to their use for energy, the proteins are used for growth
and replacement of the muscles, organs, blood and other parts of
the animal body. The minerals calcium and phosphorus are used to
form and repair bones and other tissues. Other minerals, including
sodium, chlorine (salt), iodine, iron, magnesium, manganese and
copper are needed for various purposes of the body.

Vitamins are organic compounds which are required in very
small quantities for the maintenance and normal growth of animals,
including man. Besides vitamin A and carotene, the vitamins now
known include thiamin, riboflavin, pyridoxine, niacin, pantothenic
acid, choline, inositol, para-amino-benzoic acid, ascorbicacid, vita-
min D, tocopherols, biotin, folic “acid, and probably others not yet
identified. All of these are furnished by a properly selected diet.

The failure of vision in dim light, referred to as night-blindness,
was known to the ancient Egyptians, and corrective treatment is now
known to be justified. The eating of liver was prescribed 4,000 years
ago. Not until I917 was it recognized that the cure for certain types
of night-blindness depended on the newly-recognized fat-soluble
vitamin A (3), which is present in liver;

This publication deals only with vitamin A and carotene, and
the other nutrients will not be discussed.

Vitamin A is also sometimes called fat-soluble A, or anti-ophthal-
mic or anti-infective vitamin. Its presence in sufiicient amounts pro-
motes appetite, digestion, growth and long life, maintains health
and vigor, prevents certain infections especially of the eyes and
lungs, and is essential for normal reproduction, lactation and rear-
ing of the young. When deficient or when absent from the diet,
young animals may suffer from retardation of growth. Older ani-
trials, when the bodily stores of vitamin A are exhausted, and when

*Retired July 31, 1947.

6 rBzU-LLETIN NO. 690, TEXAS AGRICULTURAL EXPERIMENT STATION»

 
  
   
   
    
   
  
  
   

receiving insufficient vitamin A or carotene, may sufier from 10 
of appetite, night-blindness, infections of the eyes, kidneys, bladf
der and alimentary canals. Vitamin A occurs in livers, milk, butte
and eggs. Some fish liver oils contain high amounts of vitamin A.,;

Carotenes occur in plants, especially in green or yellow parts of
them. They can be converted to vitamin A in the animal body. Caro-
tenes are yellow in color, While vitamin A is colorless. There are“
several carotenes, namely beta-carotene, which is of most common if
occurrence, alpha-carotene, which occurs less frequently, gamma- A
carotene, of infrequent occurence, and cryptoxanthin, which is pres» 1
ent in yellow corn. In addition, there are several isomers of caro- A
tenes, those of most frequent occurrence in foods being neo-beta- i
carotenes B and U. (50). According to Sexton, et al. (55), caro- a
tene eaten by rats is converted to vitamin A, but carotene intro- 3
duced into the veins or muscles is not converted to vitamin A, so
that the transformation of carotenes to vitamin A probably occurs i
in the walls of the intestines. I

Estimation of Vitamin A Potency and of Carotenes

Vitamin A potency is usually determined by measuring the
growthof rats fed upon a ration complete except for vitamin A.
Young rats. just weaned are first depleted of vitamin A by feeding
a ration devoid of vitamin A until growth ceases. They are then
divided into groups such as from 6 to IO rats each, the groups being

equalized with respect to weight and sex. Two or more groups re-
ceive, twicea week, U.S.P. Reference oil or beta-carotene dissolved j‘
in oil in definite quantity such as to furnish 2, 4 and" 6 Interna-
tional units. Other groups are fed the material to be tested to fur-
nish similar quantities, such as 4 International units. The rats are
weighed weekly, and after feedingthe vitamin or carotene for 28

' days, the average gains in weight for each group are compared,

"such as by plotting upon semi-log paper. By comparing. with the
gains made on the reference oil or beta¢carotene, the number of
International units is estimated per gram of the food tested (I2,
so. 4s)- .
qOne International unit of vitamin Ais defined as the potency of
o.6-micrograms of beta-carotene dissolved in coconut oil. The U.S.P.
unit has the. same value. Where the word unit is used in: this bul-
letin,..it_ means either U.S.P. or International unit. VitamimA po-
tency was formerly measured as Sherman-Munsell units; one unit
of which‘ in-this laboratory was equal to 1.2 International units. (35).
Vitamin A is also estimated in solutions properly prepared by
measuring the absorption of light at 328 millimicronsby means-of

VITAMIN A AND CAROTENE IN HUMAN FOODS" ‘ 7

a spectrograph. For details see references 24, 3o or 2, ‘page 599.
Vitamin A as determined by us with the spectrograph was termed
spectro-vitamin A. A . ~

_ The vitamin A potency (30) of 1 microgram of spectro-vitamin
A averaged 3.0 units in beef liver containing more than 43 micro-
grams per gram of spectre-vitamin A, 1.5 units for those contain-
ing 1.5-2.7 micrograms, and 1.2 units for pork liver containing
19.5-78.3 micrograms of spectro-vitamin A per gram (30).

r Vitamin A is also determined by means of the blue color formed
 when it reacts with antimony trichloride. A

 
   
 
 
 
   
 
   
   
 
   
   
   
  
   
 

Carotenes are determined, after separation and purification, by
. measuring the yellow color visually in a colorimeter, by means of a
photoelectric colorimeter, or by‘ a visual spectrophotometer. Several
‘ methods of preparation and purification have been used. One method
- of purification is shaking with magnesium carbonate (20, 26). De-
tails of the method used by us are given in reference 1, page 60o.
A later method adopted by the Association of Ofiicial Agricultural
a Chemists is given in reference 42. -

Lycopene is present in apricots, red peppers, tomatoes and wa-
termelons, and is not removed by the ordinary absorbent (25),. In
order to avoid too high results, magnesium carbonate especially pre-
pared and tested, may be used (25). -

Whatever method is used to determine carotenes, the result is al-
=most always a mixture of several carotenes, and often contains im-
‘ purities which are not carotene (44, 50). Carotenes can be sep-
arated from one another by concentrating the solution, pouring it
5 upon calcium hydroxide or some other absorbent in a glass tube,
_ and washing with petroleum naphtha until the carotenes’ separate
‘into different zones. The zones are then cut apart, the carotenes dis-
isolved, and the ‘quantities of each determined. The method is de-
éSCflbfid in full in reference 2, page 600.

a Neo-beta-carotene B has been reported (43) to have one-half the
vitamin 1A potency of beta-carotene, and neo-beta-carotene, U to
, ave one-fourth the value (47). Alpha-carotene and cryptoxanthin
 e considered to have one-half the vitamin potency of _beta-car0_-
ene (21).
Variations in Vitamin A Content of Livers h

 Caroiitfenerconsumed in animal feeds is converted to vitamin A
‘fwhich is used primarily for maintenance and in animal products,

such" as eggs or milk, but any excess may be stored “in the body,
chiefly in the liver. When pastures are green and forage plentiful,

s‘ BULLETIN-“NO. 690, TEXAS AGRICULTURAL EXPERIMENT STATION

   
  
  
  

lajrge quantities of fvitamin 'A' may be found "in the livers of Eherbivori
ous animals. When the forage ‘grasses become older, theicarotenii
content is lower, and when they dry up, the carotene content’ is veryi
low; Under “such conditions, ‘the ‘vitamin Aiin the liver decreases. T
The livers of animals rfattened upon feed containingi littleiorno

i, Table 1. " Vitamin A content of some livers

    

Vitamin A potency
units per gram
Beef livers as purchased in College Station or Bryan,'Texas .

lliver.-....».- . . . . . . . . . . ..- . . . . . . .  . . . . . . . . . . . . . . . _ .  ‘I062

~4 ' ~ 678-740

5 477-546

3 ' 423-444

I 6 323-397

7 ' 220-292

i .2. ' 99-126

1 ' 24 _ ~
Average . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. _ 418

Beeflivers from animals depleted of vitamin A and then fed def-
iaige arnounts of carotene, micrograms per 100 pounds"
, 41

l0 livers, fed 791 micro. carotene . . . . . . .._ I . . . .  . . ._ . . . . . . . . 3

l0 livers, fed 981 micro. carotene . . . . . . . . . . . . _ . . . . . . . . . . . . . . 3

l0 livers, fed 1.41.0 micro. carotene . . . . . . . . . . . . . . . . . . . . . . . . . . 4

10 livers, fed 1839 micro. carotene . . . . . . . . . . . . . . . . . . . . . . . . . . 3 t

l0. livers, fed 1872 micro. carotene . . . . . . . . . . . .‘ . . . . . . . . . . . . . . . 4

10 livers, fed 2830 micro. carotene . . . . . . . . . . . . . . . . . . . . . . . .  5

10 glivers. fed 5328 micro. carotene. . . ., . . . . . . . ._ . . . . . _ . . . . . . . . . ‘J
Beef livers, steers fed silage for 126 days, carotene in, micrograms _
per 100 pounds a -
l0 livers, cottonseed hulls, no carotene , . . . . . . . . . . . . . . . . . . . . . ‘ll
~ 10- livers, sumac silage, fed 22828’. . . . . . .~ . . . . . . . . . . . . . . . . . . . . 100
l0 livers, sumac silage. fed 28510. . . .' . . . . . . . . . . . . . . . . . . . . . . 92
10 livers, hegsri silage, {ed 15455 . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Call’ liver, purchased V _ -
2 livers. . L ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ~ 408 432 i;
1 liver- . . . . . . . . . . . . . . .  . . . . . . .  . . . . . . . . . . . . . . . . . . . . .  210 3
1 liver . . . . . .;;.; . . . . . .  . . . . . . . . . . .  . . . . . . . . . . . . . . . . . . . .. 132 i
2.livers . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . . . . . . . .  . . . . . .. . . 84-87 
Calf liver, very young calves . .
4 livers . . . . . . . . .  . . . . . . . . . .  . . . . .  . . . . . . . . . . . . . . . . . . .. 1~~7
1 liver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . .._ . . . . . . . . . . .. 30
Cali liver, very yollllfl, calves, Mothers on , -_ .
1000 micrograms per 100 pounds . . . . . . . . . . . . . . . .» . . . . .  . . . . I!

2000 micrograms . . . . . . . . . . . . . . . . . . . ; . . . . . . ._ . . . . . . . . . . . . . . . »5 _

2500 micrograms . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . . . . .» . . . . . . . 7

vitamin A deficient, 13 livers. . . ., . . . . . . . . . . . . . . ._ . . . . _ . . . . . . 1-4

normalcows . . . .  . . . . . . .  . . . .  . . . . . .. 4-0
Sheep livers - - - - ~ ~

on good pasture, 2 livers.'.'. . 1 . . . . . . . . . . . . . . . ; . . . . . . . . . . . . . 760-1050

on poor pasture.‘1-liver.,..».......- . . . . . . . . .; . . . . . .  . . . . .. @370 ~ -
Lamb liver . _ U " - A -' -  »

poor pasture. 2 livers . . . . . . . . . . . ." . . . . . . . . . . . . . . . . . . . . . . . .. 270-370
Goat livers

Vitamin A deficient, 16 livers . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-10

Normal fed, 1 liver . . . . . . . . . . . . . . . . . . . . . . . . . ._ . . . . . ._ . . . . . . . . V 150
Swine livers-purchased

2 livers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . 234-250

A 5livers,;...‘..,....;-.";» . . . .  . . . . .  ~ 48-77.

4 livers . . . . . . . . . . . . . . . . . . . . . .' . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-35

1_liver,.....",‘....-...,...._.;..."._.__..;_...-;.".; . . . . . . .  _ l9 ~

Average . . . .  . . . . .  ~ f",

. VTTAMIN A AND CAROTENE IN HUMAN FOODS 9

carotene may be very 10w in vitamin A. The vitamin A content of
animal livers may often differ widely, according to the nature 9f
the feed. " '

Table 1 shows the vitamin A content of livers purchased in Col-
lege Station or Bryan, or from animals receiving known quantities
of carotene. The beef livers purchased contained from 24 to 1,062
units of vitamin A per gram with an average of 418. Most of the
animals evidently had access to good pasture. The livers of ani-
mals depleted of vitamin A and then fed rations containing known
low amounts of carotene (40, 41), contained from 3 to 9 units of
vitamin A per gram. Even 5,328 micrograms of carotene fed daily
per 10o pounds of live weight of steer allowed very little
storage of vitamin A. The livers .of steers fed "daily from 15,458 to
22,828 micrograms of carotene per I00 pounds live weight averaged
92 t0 10o units of vitamin A per gram. Those receiving no caro-
tene for 126 days still averaged 21 units per gram of liver, evident-
ly because the previous stores of carotene in the livers had not been
entirely depleted in 126 days of feeding. i " '

Calf livers purchased on the market contained from 84 to 432
units of vitamin A per gram. Evidently these calves had accesspto
good pasture. The livers of very young calves averaged very low in
vitamin A; most of them contained only 1 to 8 units per gram.
Livers from sheepon pasture contained 370-1050 units of vitamin
A per gram, those from lambs, 270-370 units. Swine liver contained
from 19 to 250 units xiitamin A pertgram.

The vitamin A contents of liverssold on "the market evidently

' range widely in vitamin content. Thelivers purchasedat "College

7 Station and Bryan (Table 1)" may "be from animals which" received

i more carotene," through accessito pastures," than many ofYthe other
animals marketed. "Evidently "the ‘subject needs morestudy." i

A The effect of the quantity of carotene in the food on the vitamin

_ A content of. chickenlivers ‘is’ shown in Table 2. Analyses were

rnadeofdlivers of chickenslfed by the Department,’ of ‘Poultry Huse

bandry immediately afterhatchingiwith ‘rations. containing. .2, 6 and

12 parts per millionof icaroteneinl-alfalfar leaf imeaili. At the tthdflhi

' each period of 4 wé@1;s,"6éhi¢h¢hs" from ettthgtottp" ivereukilledilanld

the livers" s'ubject"e"d_ m" htttt1ys;i§,* with the téstilts ‘as "shown" ittlrahlt

t 2. Thetiutihtititts ofvitaminilAi ht thelliversj "wererelated" "to" the

quantities h; ttttthtehe" that. iTltékt-"ltamin" A‘ pOl€i1éY“-_0f ' thetiivitth

1'0 i BULLETIN. No. s90. TEXAS AGRICULTURAL EXPERIMENT STATION

Table-z." "Averagevitamin A content andweights of liversin chickeT

atdifferent periods of growth, averages of..6

 

Average weight of liver, Approximate units of
grams vitamin A per gram of liver
Carotene in feed in parts ~~~~~ -— —~ _ ' ' .
per million June July Aug. Sept. May June July Aug; Sept. i
. . - 30 l8 15 l2 22 . 30 l8 l5. l2 _'
l
2 . . . . . . . . . . . . . . . . . . . . .. 9.4 1 .0 15.2 16.3 7 8 l7 l6 l5 ‘
 9.4 15.3 l4.7 l4.3_ l5 27 50 36 3|
12.... . . . . .  . . . . .. l0.8~ I .8 15.3 1419 22 108 279 207 285

 

reacheda maximum at the end of 12 weeks, after which it was con- A
stant in the" diets furnishing 2 parts per million of carotene, ‘but ir- .

regular in the diets containing 6 to I2 parts per million.

In each group, there were considerable individual differences in
vitamin A content per gram of liver. For the first series of May 22,1
with averages of 7, I5 and 22 units per gram, the standard devia-
tions were 2.6, 6.0, and _I7.o. That is to say, the standard deviations
were approximately 37, 40 and 77 percent of the average. With the "-
series of August 15, withaverages of I6, 36 and 207 units, the A
standard deviations were 4.5, 19.4 and 36.3, equal to about 28, 54, I
and I8 percentiof the average. There were less differences in the
vitamin A content of the livers of the older birds on the same feed f

than ‘of the younger ones.
Variations in Butter, Milk and Cheese

The vitamin A contents of animal products, such as milk, butter
and eggs, depend upon the carotene content of the feedat the time
such products are produced, and on the vitamin A stored in the liver.
Hence, it often ‘happens that the vitamin A content of milk is high
atthe beginning of lactation, and gradually decreases. Eggs, like-

  
 

wise, may have higher contents of vitamin A when laying begins 
than at subsequent periods. Table 3 indicates the relation of the “
kind and quantity of the carotene in the feed to the vitamin A po- u?

tency of butter, as derived from experimental work (I7). The vita-
miniA potency of the butter ranges from 5 to II4 units per gram,

depending on the vitamin ‘potency of the diet at the time of col- 1

lecting the butter,'and also on the preceding diet.

Appreciablle. percentages of the vitamin A, potency may be due
to carotenein the butter. Among other data (I7), a sample: contain-
ingIo parts per millionof carotene equivalent to I 7 unitsyitamin
A potency per gram contained a total of 6o units of vitamin A per
gram. Therefore, the carotene furnished nearly 3o percent of the

VFW“. at- w._.____.._.,-_q¢,_-n~r- - W... -m-1' ~ -- —'—~—

VITAMIN A AND CAROTENE IN HUMAN FOODS 11

Table 3. Vitamin A potency of butter fat as affected by carotene content
of diet and stage of lactation

Units
per gram
Fed yellow corn
At beginning of lactation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

After l week . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5 weeks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l7

9 weeks . . . . . . . . ... . . . . . .._ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l2

l3 weeks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

l7 weeks . . . . . . . . . . . . . . . . . . _. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
» Fed yellow corn and 3 pounds alfalfa leaf meal daily
At beginning of lactation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

After l week . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5 weeks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

9 weeks . . . . . . . . . . . . . . . . . . . . . . . . . . .~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

l3 weeks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .j l7

l7 weeks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l4
Fed yellow corn and 6 pounds alfalfa leaf meal daily
At beginning of lactation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

After l week . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

' 5 weeks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 '

9 weeks . . . . . . . . . . . . . . . . . . . . . . . . . . ._ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

l3 weeks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

l7 weeks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l2
Depleted of vitamin A and placed in good pasture
At beginning . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l4

After ‘l day . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2 days . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

3 days . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

4 days . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

7 days . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . ._ 40

l4 days . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .- . . . . . . . . . 48
Approximate number of units fed per cow per day
None . . . . . . . . . . . . . . . . . . . . . . . . . . _. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l0

8,000 units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . l2

, l0,000 units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . . . . l0

20,000 units...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . .. 8

72,000 units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l6

140,000 units.._ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14

200,000 units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

400,000 units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ‘ 28

540,000 units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .- . . . . . . . 50

900.000 units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . 78

l.700.000-units . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 114

yitamincA potency. Another sample with 5 parts per million of

plcarotene (8 units, per gram) contained 34 units 0f vitamin A; thus,
i24 percent of the total potency was derived from carotene. A high
natural yellow color of butter is usually an indication of high vita-

min A potency. Artificial yellow color may conceal inferiority. -.of

‘ibutter so far a.s vitamin A is concerned.

In studies of 62 samples by Kemmerer and Fraps in 1942 (43),
the-vitamin A content of Texas market butter ranged from 20.7

-.to 52.6 units per gram. The averages by months are givenTin Table
?4. The average vitamin A content does not differ‘ widely from.
lxnonth tomonth, and for the year is 37 units per gram, equal to

16,798 units per pound. In some other states, ‘the vitamin Acon-

ltent difiers at different seasons of the year. The grand average for
1a numberof states is given as 14,529 units per pound 

12 BULLETIN No. e90, TEXAS AGRICULTURAL EXPERIMENT sqwrron

Table '4. Vitamin A in ‘commercial butter sold-in Texas s.

l Average’ units
Month of collection per gram
January; 1942 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3’!

March . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3a

April‘ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

June._ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

July . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

August . . . _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . 30

September . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

October . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

November . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

January, 1943 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . .. 38

Average . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Some brands of oleomargarine (margarine) are fortified with

vitamin A concentrates so as t0 be guaranteed to contain either’ ‘

9,000 or 15,000 units per pound. The vitamin A present, if any,
should be stated on the label of the package. ‘

Fresh whole milk averages 3.9 percent fat. The vitamin-A is con-
tained in the fat. The vitamin A content of the milk, as with but-
ter, depends on the carotene content of the diet of the cows.

The vitamin A potency of dried whole milk, cheese and ice cream p
dependson the butter fat content and the previous diet of the cow f?

which produced the milk, and hence varies as pointed out above.
If ice cream is made from dried whole milk, it may contain less
vitamin A than if made from cream, as there is some loss during
storage of dried milk (33).

Cows on abundant pasture consisting of green grasses or alfalfa

orflotherlegumes, or fed good grass silage or legume silage are i

likely to produce butter highest in vitamin A potency. When the

grasses are old or dried up, or when corn silage or sorghum “silage '

are fed, the butter produced is medium in vitamin A content. Fod-

ders and hays fed as roughages withoutipasture, produce butter ~

low in vitamin A, as do also corn, grainsorghurn, oats, barley, straw
andold fodder. i ‘ i

Variation in Eggs

The ciuant-ity of vitamin A in eggs is related to the vitamin A 
potency of the diet and of the previous diet, from which vitamin A i
has been stored in the body of the hen. Data secured by biological 

methods in one of several experiments (58) are shown in Table 5.
It is seen that the vitamin A potency depends upon both the vita-

min, A potency of the diet and the length of time the bird has been *
laying. Part of the vitamin A potency of the egg is due to caro- 
tene, but most of it is due to vitamin A. Some mixed poultry feeds <_'

 

VITAMIN _A AND CARQTENE m HUMAN_ FOODS a y _ 12

Table .5. Relation between vitamin A potency of the diet and vitamin rA
‘ ' ‘ a potency of ‘yolks of the eggs produced  ' "

llnits per gram of yolk i
180i units .305 units 401 units
fed daily ‘fed ‘daily Ted daily

January, I934 . . . . . . . . . . . . . . . . . .  . . . . . . . . . . .  . .  . 

3 _ 7 s i2
lgiebrulilry . . . . . ... _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..- . . . . .. I2 l3 -l9

arc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. 8 l0 l7

Aprilj...‘ . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . . . .. l1 ,_ ll 22

:11)’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . g  

une . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ~ ' *

July . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6 p 8 l3

August . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. >6 p_ 7 l_l

  
   
  
 
 
   
 
  
   
  
   
    
    
   
 

contain fish liver oil concentrates to supply vitamin A, but fowls
having ‘access to pastureor green feed secure vitamin A potency
from carotene. ‘Dark yellow‘ egg yolks "are likelyi to“ contain more
vitamin A potency than light-colored yolks.

Variations in Yellow CornDue to Heredity

The carotene content of yellow corn depends upon the length of
' time of storage, the heredity and other factors. Corn may have I,
'2 or 3 genes for yellow color. The quantity of carotenes depends
l upon whether 1, 2 or all 3 genes for yellow color arepresent (51).
A The number of genes for yellow does not affect appreciably the
relative proportions of the alpha, beta and K caroteneand crypto-
g xanthin which are present (49). '

Constituents of the Carotenes of Some Human Foods

~‘ _ When carotene extracts in petroleum naphtha were concentrated
and transferred to a column of calcium hydroxide or some other
solids, zoneslof different pigments were developed by washing ‘the
§ column with petroleum naphtha alone or mixed with I to 5 percent of

‘thin of yellow corn from some of the other carotenes.

_ Table 6 contains the carotene constituents of some human foods
as separated by calcium hydroxide (4.4). Therawleafy vegetables
average 76 percent beta-carotene, IO percent neo-beta-carotene U, 8
percent neo-beta-carotene B and 6 percent of impurity A. Cooking
Ythe leafy vegetables increased the average neo-beta-carotene B from
*1 8 to 18 percent, the neo-beta-carotene U from IO to I 3 percent, and
decreased the beta-carotene from 76 to 63 percent of the total "crude
gcarotenes, thereby decreasing the vitamin A potency. Cooking has a
similar effect on other vegetables, although the increase in neo-

‘ acetone (44). Calcium hydroxide does not separate the cryptoxan- _

l war-carotene U“ is‘ “iisiiallymless"mtliafintliaitimoflneoibétaécarotene“ “B.” l‘ ' l

14 BULLETIN NO. 6'90, TEXAS AGRICULTURAL EXPERIMENT STATION

Dehydrating likewise usually increases these two isomers, althou i

to a less extent than cooking. Squash, pumpkin and carrots con
alpha-carotene. The pumpkins purchased locally contained only

percent of alpha-carotene, while the 3 samples of canned pumpk"

evidently from a different variety, averaged 25 percent alp

carotene. Some carrots contained about 3o percent of alpha-car
tene while other samples of carrots contained about 22 percent (46_f
Storage decreased the percentage of beta-carotene in some of t,“

foods tested and increased the percentage of neo-beta-carotene
almost all of them (23).

  

 
  

 
  
  

Table 6. Constituents of crude carotene of some foods
Neo- Neo- Beta-carotene
Number Impurity beta Beta beta Alpha equivalent of W
averaged A carnfitene carotene canatene carotene crude Carotene 
% % % ‘70 % % ~
Lealy vegetables, raw

Beet greens . . . . . . . . . . . . . . . . . . . . . . . . l 4 l0 76 l0 0 _ 84‘

Broccoli, Italian Sprouting . . . . . . . . . .. l l3 l 80 6 0 83

Collards . . . . . . . . . . . . . . . . . . . . . . . 3 7 ll 73 9 0 77 

Mustard greens . . . . . . . . . . Z 6 l0 77 A7 0, 83 3'

Spinach . . . . . . . . . . . . . . . Z 6 9 78 7 0 84- 

wiss -c . . . . . . . . .. 3 6 l3 73 8 ‘ 0 80 ‘ i‘

Turnip greens . . . . . . . . . . . . . . . . . . . . . . 4 4. 10 79 7 0 85

Average leafy vegetables . . . . . . .. I6 6 l0 76 8 0 33
Leafy vegetables, cooked
Beet greens, boiled 20 min . . . . . . . . . . . l 4 l3 67 l6 0 53
Collards, boiled Z0 min . . . . . . . . . . . . . . l 9 l0 55 Z6. 0 7l ‘
Mustard greens, boiled 20-30 min.  . 2 5 l7 62 l6 0 74 
Spinach, boiled Z0 min . . . . . . . . . . . . .. l 4 l2 58 Z6 0 74 “v
Swiss chard, boiled Z0 min . . . . . . . . .. l 8 l5 66 ll 75 ,
Turnip greens, boiled Z0-30 min . . . . . . Z 5 8 69 l7 l 80 -i
Average cooked leafy vegetables. . 8 . 6 l3 63 l8 0 76 I ;_,
Leafy vegetables, dehydrated f f,
B greens....‘...'. . . . . . , . . .; . . . . .. l 3 l2 75 l0 0 ' 83 ' - -

Collards . . . . . .  . . . . l Z5 ll 5l l3 0 61

Swiss" chard . . . . . . . ." l 6 l0 76 8 0 B3

Turnip greens . . . . . . . .. l 5 l3 72 l0 0 8i

Average. . .' . . . . . . . . . . . . . . . . . . . . . 4 l0 ll 69 l0 0 78
Leafy vegetables, canned " 
'nach . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4 r Zl l8 49 lZ 0 60 gj

Turnip greens . . . . . . . . . . . . . . . . . . . . .. Z l3 24 50 l3 0 63 "l,

Average i . . . . . . . . . . . . . . . . . . . . . .. 6 l8 Z0 50 12 0 6| 

Apricots, canned . . . . . . . . . . . . . . . . . . . . . . . . 3 30 Z 62 6 0 66 f

Squash, raw . . . . . . . . . . . . . . . . . . . . . . . . . . .. Z 37 3 50 5 5 55 _,

Squash, boiled . . . . . . . . . . . . . . . . . . . . . . . .. 2 45 6 35 9 5 44 

Pumpkin, raw . . . . . . . . . . . . . . . . . . . . . . . . . . l 41 Z 52 Z 3 55 .

Pumpkin, hoiled . . . . . . . . . . . . . . . . . . . . . . . . l 49 4 35 8 4 42

Pumpkin, canned . . . . . . . . . . . . . . . . . . . . . .. 3 Z0 8 37 l0 Z5 57 ,

Sweet potatoes, raw . . . . . . . . . . . . . . . . . . .. 3 l0 0 86 4 0 88 i:

Sweet potatoes, boiled . . . . . . . . . . . .. 5 l6 0 68 l6 0 76 

Sweet potatoes, dehydrated . . . . . . . 8 lZ 5 69 l4 0 77 f

Carrots, raw . . . . . . . . 4 5 l 62 3 29 78 

Carrots, boiled . . . . . . . . . . . . . . . . . . . . . . 4 5 Z 50 ll 32 6l g,

Carrcts, dehydrated . . . . . . . . . . . . . . . . . . . .. 5 7 l 65 5 22 70 "-5

Carrots, fresh, College Station . . . . . . . . . . . . 7 6 l 59 2 32 76 J

Carrots, dehydrated, California . . . . . . . . . . . 4 6 l 66 6 Zl 80

Carrots, dehydrated, Texas . . . . . . . . . . . . . . l7 i l0 l 53 2 34 7l 

Carrots, dehydrated, California . . . . . . . . . . . 5 l3 Z 49 3 33 68 ‘T’

Yellow corn . . . . . . . . .  . . . . . . . . . . . . . . . . . . . . . . . .. 1.5 . . . . .1 . . . . . . . . . . . . . . . . . . . . . . . . .. 64 5

l Neo-cryptoxanthin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

VITAMIN A AND CAROTENE IN HUMAN FOODS l5

When separated bymeans of a column of magnesiumloxide, the
crude carotene of yellow corn (A21) had the composition given‘ in
Table 7. The corn in Group 2 contained less beta-carotene andmore
neo-cryptoxanthin than the corn in Group I. Biological tests (21)
showed that the K-carotene, the cryptoxanthin and the neocryp-
toxanthin have approximately one-half the vitamin A potency of
beta-carotene. Magnesium oxide did not separate the neo-beta-caro-
tene U and neo-beta-carotene B from the corn as was done for the
foods listed in Table 6, while calcium hydroxide, used for work rep-
resented in Table 6, did not satisfactorily separate the cryptoxan-
thin. The two ‘reagents used in combination might give the (lesired
separation of the carotenes in corn. a

Table 7. Percentage composition off crude carotenes of yellow corn

Group 1 ' Group 2:
18 samples :4 samples‘

Impurity A . . . . . . . . . . . . . . . .' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Beta-carotene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .> . . . . . . . . . . . . . . . .

Alpha-carotene . . . . . . . . . .7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

K-carotene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _. . . . . . . . . . . .

Cryptoxanthin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

l-HB G9
UINUHB¢H
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Nib

Beta-carotene Equivalent of Carotenes in Vegetables

Neo-beta-carotene B, alpha-carotene and cryptoxanthin have one-

' half the vitamin A activity of beta-carotene, and neo-beta-carotene U
lhhas one-fourth its activity (47). It follows that the total carotenes
i of foods, as listed in Tables 6 and 7, have less activity per unit than
 has beta-carotene. The beta-carotene equivalent of the crude caro-
f; tene, including impurity A, and of the carotenes only, exclusive of
{impurity A, are given in Table 6. The beta-carotene equivalent of
 raw leafy vegetables averages 88_ percent, that of cooked leafy vege-
tables, 8o percent, that of canned leafy vegetables, 74 percent, and
E,- that of dehydrated leafy vegetables, 87 percent of beta-carotene.
 As examples of other foods in Table 6, the beta-carotene equivalent
a of the carotenes of boiled squash is 8o percent, baked pumpkin, 85
r percent, baked sweet potatoes, 9o percent, and boiled carrots, 64
“A percent. To calculate the beta-carotene equivalent of beet greens,
 for example, multiply the crude carotene (determined by the meth-
 od used in this work) by .84 or the pure carotene by .87. The beta-
 carotene equivalent of other foods can be calculated in a similar

16 BULLETIN NO. 690, TEXAS AGRICULTURAL EXPERIMENT STATION

way. Cooking or canning decreases the beta-carotene value of the?
foods concerned, because some of the beta-carotene is converted into;
its isomers having lower values.

Q

Elfect of Cooking, Canning and Storage

Cooking has little destructive effect upon vitamin A or carotene, ‘i
although it may reduce the value of beta-carotene by converting’;
some of it to neo-beta-carotene B or U, as shown previously. _

Guerrant, et al. (36), reported losses of‘ carotene occur in the can- a
ning of all foods containing it. Carotene retention was excellent in 
the canning of asparagus, cherries, squash and tomatoes, good in car- '3
rots, yellow corn, peas and tornato juice, and fair in snap beans.

  
   
  
 
  
  
 
 

The amounts of carotene in yellow corn decrease in storage (39). i
In some experiments the_loss ranged from 3 percent in 5 months to
II percent in II months at refrigeration temperatures. (19) At
higher temperatures the loss was greater. Some work indicates that ~
the loss may be 50 to 7o percent in a year (39). Powdered whole
milk may lose 6o percent of its vitamin A potency in 9 months
(12). A loss of carotene occurs when foods are dried; if dried
rapidly, the loss may be small, but carrots may otherwise lose 8o

percent, spinach, 65 percent, and sweet potatoes, 29 percent (12, '
s4)-

Digestibility (of Carioteniesi

Very few digestion expariments with carotene have been made on
humans (32). It has been reported that 10.5 percent of the caro-
tene of carrots and 41 percent of the carotene dissolved in oil was
digested by humans. Fraps and Meinke (32) reported digestion
experiments on carotenes with adult rats as given in Table 8. When
2o micrograms per day of crude carotene was fed, the digestibility
of beta-carotene in I7 tests ranged from 8 percent with boiled car-
rots to 55 percent with boiled mustard greens and averaged 44 per~
cent with the greens and 32 percent with the other vegetables. In e_
14 tests, when the rats received 6o micrograms of crude carotene per
day, the digestibility of beta-carotene ranged from r18 percent with
canned pumpkins to 49 percent with raw carrots and averaged 41
percent with the greens and 34 percent with the other vegetables.
The digestibility of beta-carotene dissolved in oil was 57 percent
and 64 percent with 2o and 6o micrograms respectively fed per day.

With young growing rats fed (31) 6o micrograms of carotene
per day per rat, the average digestibility of carotene in vegetables,
9 tests, was 52 percent for beta-carotene and 53 percent for alpha-

 

VITAMIN A AND CAROTENE IN HUMAN FOODS 17

Table 8. Average percentage digestibility of carotenes by rats

Neo-beta
Beta- Neo-beta- Alpha- and beta-
carotene carotene carotene carotene
Fed 20 micrograms per day per adult rat
Carotene in oil (1) . . . . . . . . . . . . . . . . . . . . . 57 . . . . . . . . . . 60 57

Apricots, canned (1) . . . . . . . . . . . . . . . . . . . 31 31 . . . . . . . . . . 31

Beet greens, boiled (1) . . . . . . . . . . . . . . . . 51 62 . . . . . . . . . . 53

Carrots, raw (3) . . . . . . . . . . . . . . . . . . . . . . . 22 28 43 . 22

Carrots, boiled (2) . . . . . . . . . . . . . . . . . . . . . 8 9 45 8

Mustard greens, boiled (1) . . . _ . . . . . . . . . 55 73 . . . . . . . . . . 59

Potatoes, sweet, baked (3) . . . . .. . . . . . . . . 30 51 . . . . . . . . . . 35

Pumpkin, boiled (2) . . . . . . . . . . . . . . . . . . . 11 8 41 10

Spinach, canned (2) . . . . . . . . . . . . . . . . . . . 22 41 . . . . . . . . . . 31

Squash, boiled (1) . . . . . . . . . . . . . . . . . . _ . . 43 61 . . . . . . . . . . 46

Turnip greens, boiled (l), . . . . . . . . . . . . . . . 43 61 . . . . . . . . . . 46

Average, vegetables (10) . . . . . . . . . . . 32 42 (4) 47 34

Average, greens (4) . . . . . . . . . . . . . . . . 44 59 . . . . . . . . . . 47
{i0 micrograms per day per adult rat
Carotene in oil (1) . . . . . . . . . . . . . . . . . . . . . 64 . . . . . . . . . . 72 57

Carrots, raw (2) . . . . . . . . . . . . . . . . . . . . . . . 49 . . . . . . . . . . 32 46

Carrots, boiled (3) . . . . . . . . . . . . . . . . . . . . . 25 ' 35 39 . 27 .

Potatoes, sweet, baked (3).... .. . . . . . . . . 33 56 . . . . . . . . . . 38

Pumpkin, canned (2) . . . . . . . . . . . . . . . . . . 18 . . . . . . . . . . 28 ll

Turnip greens, canned (2) . . . . . . . . . . . . . . 41 48 . . . . . . . . . . 44

Spinach,canned(2).................... 40 63 . . . . . . . . .. 46

Average, vegetables (6) . . . . . . . . . . . . 34 '34 (3) 33 35

Average, greens . . . . . . . . . . . . . . . . . . . 41 56 . . . . . . . . . . 45

carotene, compared with A70 and 63 percent for carotene dissolved
in oil. The beta-carotene in vegetables was digested 76 percent and
the alpha-carotene 84 percent 0f that of carotene in oil.

Utilization by Rats of Carotenes in Vegetables for Vitamin A Potency

The International biological unit of vitamin A is 0.6 microgram
of beta-carotene dissolved in coconut oil. It was shown in the pre-
ceding section that carotene dissolved in cottonseed oil is more di-
gestible (57 percent) than carotene naturally occurring in greens
(41 percent) or in other vegetables (34 percent). It is, of course,
necessary to bring the carotene in solution during the process of
digestion. »

At a low level of feeding, however, suflicient for only slight or

. moderate growth of rats, the vitamin A value of the beta-carotene

equivalent in plant materials appears on an average to be nearly
equal to that of beta-carotene dissolved in cottonseed oil. Results
of experiments with 27 samples (45) are summarized in Table 9.
Carrots had lower values than the other foods. The value of caro-
tenes for slight growth of rats appears to exceed their values as
indicated by digestibility. With carotene in oil as 10o, the relative
digestibility of greens would be 8o, and of vegetables 6o, while the
average relative vitamin A value would be 93. These experiments

l8 BULLETIN NO. 690, TEXAS AGRICULTURAL EXPERIMENT STATION

Table 9, Relative efficiency of carotene in foods and feeds compared with
carotene in cottonseed oil as measured by gains in weight

Relative gain
Number of in weight
Food tests Beta-carotene
averaged in oil as 100
Apricots, canned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . l I03

Beet greens, cooked . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. l 80

Carrots, cooked . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 64

Carrots, raw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 79

Collards, cooked . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . 2 94

Mustard greens, cooked . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 I03

Potatoes, sweet, cooked . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 99

Pumpkin, canned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l 100

Spinach, canned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 105

Swiss chard, cooked . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l 86

Turnip greens, cooked . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4 95

Alfalfa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 109

Average . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

were made with white rats; similar results may possibly occur with
humans, but only further experiments can definitely decide this
question.

When vitamin A or carotene is fed in excess of the requirements
of the animal, vitamin A maybe stored in the animal body, chiefly
in the liver. The value of carotene in vegetables for storage of vita-
min A in the livers of rats is much less than its value for mainte-
nance and growth.

In I9 tests on 6 feeds, the storage from carotene, on the basis of
the beta-carotene equivalent, ranged from 16 to 64 percent of that
of carotene dissolved in oil, with an average of 32 percent (31). A
summary of the tests is given in Table IO. In 4; tests with raw beef
liver and butterfat, the storage from the beta-carotene equivalent
of the carotene and vitamin A averaged I79 and 145 percent, res

Table 10. Liver storage of vitamin A from carotene of various foods
as compared with carotene in oil

 

Relative storage
Number of From From
tests purified beta-carotene
carotene- equivalent
Carptene in oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . l7 100 100

Apricots, boiled . . . . . . . . . . . . . . . . . . . . . . . . . . . . l 49 ~ 64

Apricots, dried, raw . . . . . . . . . . . . . . . . . . . . . . . . 1 l2 » 16

Carrots, cooked . . . . . . . . . . . -. . . . . . . . . . . . . . . . . 2 29 37

Carrots, raw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 31 36

Potatoes, sweet, cooked . . . . . . . . . . . . . . . . . . . . 4 l4 ‘ l6

Pumpkin, canned . . . . . . . . _ 4 18 24

Spinach, cooked. .A . . . . . . . . . . . . . . . . . . . . . . . . . 1 37 47

Turnip greens, cooked . . . . . . . . . . . , . . . . . . . . . . 3 l5 l9

Alfalfa leaf meal . . . . . . . . . . . . . . . . . . . . . . . . . . . l 59 71

Liver, raw beef . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 163 179

Butter fat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2- 140 145

Average of vegetables . . . . . . . . . . . . . . . . . . . . . j . . . . . . . . . . . . . . . . . . . . 32

VITAMIN A AND CAROTENE IN HUMAN FOODS l9

sP€ctive1y,"-of' that ofcarotene in oil. In 26 tests, cottonseed oil‘ in-
creased the utilization of carotene in vegetables when added to the
basal rationor added directly to the carotene supplement (31).
The digestibility of carotene in oil is greater than that of caro-
tene in vegetables, so that the digested carotenes should have higher
values for storage in livers than the total carotene. If the average
storage of vitamin A in the liver from vegetables is 32 percent of
that of carotene in oil, and the average digestibility of the caro-
tene in vegetables fed young rats is 76 percent of that in oil, then
' the storage of the digested carotene in vegetables should be 43 per-
cent of carotene in oil. The average of 9 tests with young rats (31)
gave the relative storage of 26 for digested beta-carotene equiva-
lent and 28 for total beta-carotene equivalent, which values are
much less than the calculated values.
When storage of vitamin A is desired, liberal allowances of
A carotene must be fed.

Chlorophyll occurs in green vegetables, and xanthophyll occurs
in both green and yellow vegetables. Chlorophylls and xanthophylls
when fed with carotene dissolved in cottonseed oil decreased the uti-
lization of carotene for storage of vitamin A in livers about 20 per-
cent (48). Sulfasuxidine or alpha-tocopherol fed in a basal diet
' containing lard, did not affect the utilization of carotene in spinach
for storage of vitamin A in the liver. Carotene dissolved in oil had
a lower digestibility when fed in a ration made bulky with cotton-
seed hulls, but not when it was made bulky with agar (13). Sub-
‘ stitution of casein for part of the corn meal in the diet increased
A, the digestibility of carotene and the storage of vitamin A in the
1 liver (13). ' '

   
   
  
   
 
    
  
 
 

Effect on Rats of Insuflicient Carotene in the Diet

, The vitamin A content of the ration, according to Sherman and
a associates (57), affects the length of life of white rats and the
 length of the reproductive period of the females. In experiments
1‘ reported by Fraps (15), rats were fed on rations containing 0.5,
 1.0, 2.0, 4.0 and 5.0 parts per million of beta-carotene; as the amount
of carotene increased, there were increases in the number of litters,
 the number of young, the percentages born alive, and the live weights
‘ of the young rats at the time of weaning. The percentage weaned
9 of those born alive reached a maximum of 80 at 2 parts per million
Liof beta-carotene. Swine on rations deficient in vitamin A during
periods of gestation gave birth to pigs without eyeballs, or with
 various combinations of eye defects ‘according to Novaes (52) and
Hale (37, 38) *

20 BULLETIN N0. s90, TEXAS AGRICULTURAL EXPERIMENT STATION
Human Requirements for Vitamin A and Carotene

According to Rosenberg (54), fairly uniform requirements for
vitamin A have been established for man, horse, dog, cattle, sheep,
swine, rabbit, rat and hedgehog. According to him, all show approx-
imately the same minimum requirements of 2o units of vitamin A or
25 micrograms of beta-carotene per kilogram of body weight, which
would be equal to 90o units or 1,136 micrograms per 10o pounds.
These values represent the minimum for normal growth without
showing any clinical symptoms of vitamin A deficiencies but do
not permit any storage of vitamin A. According to Rosenberg (54),
about3 times the minimum amount of vitamin A and 5 times the
minimum amount of beta-carotene should be considered minimum
for significant storage and for reproduction. The optimum vitamin
A requirement for an average adult human, 154 pounds male or 12 3
pounds female, is about 5,000 units of vitamin A or 9,000 micro-
grams of carotene. According to Rosenberg, larger amounts are
recommended for pregnant and nursing women and during adoles-
cence (54).

Recommended dietary allowances for various nutrients have been
made by the Food and Nutrition Board of the National Research

Council (10, 60). Those for vitamin A are given in Table II. The A

vitamin A recommended for an adult is 5,000 units per day.

The minimum daily requirement for vitamin A authorized by_

the U, S. Food and Drug Administration (9) for use in labeling
certain foods, is 1,500 U.S.P. unitsper day for infants, 3,000 U.S.
P; units for children more than I but less than I2 years of age, and
4,000 U.S.P. units for any person I2 or more years of age. The
quantity of vitamin A in a pound is expressed as the biologically
measured activity of vitamin A and its precursors in terms of U.S.
Pharmacopoeia units (9).

Table 11. Recommended daily allowances for vitamin A. Requirements
may be less if provided as vitamin A; greater if provided
chiefly as the pro-vitamin carotene (10)

Vitamin A
International Units

Grown man . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5000

Grown woman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6000

Woman, pregnant, latter half . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6000

Woman, lactation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8000

Children under l year . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1500

l-3 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2000

4-6 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2500

7-9 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3500

10-12 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4500

Girls over 12 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5000

Boys 13-15 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5000

Boys 16-20 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6000

<xuw

VITAMIN A AND CAROTENE IN HUMAN FOODS 21

Because by definition, 0.6 micrograms of beta-carotene dissolved
in coconut oil is equal to one international unit, or one U.S.P. unit,
5,000 U.S.P. units would be equal to 3,000 micrograms of beta-
carotene dissolved in oil.

Data presented in the preceding pages indicate that 3,000 micro-
grams of carotene in human foods is not equal to 5,000 units of
vitamin A. Biological tests (Table 9) indicate that for maintenance
or slight growth of young rats, food carotene may average 90 per-
cent of the value of that given above. Data in Table 6 indicate that
the mixture of carotenes as determined by analysis may have the
theoretical value of 80 percent of that of beta-carotene. The diges-
tibility of carotene by adult rats (Table 4) may average about 40
percent for greens and 34 percent for other vegetables. For young
growing rats it may average 50 percent. i

For reserve storage of vitamin A in the liver, the value of caro-
tene is much lower than that of vitamin A. Table IO indicates that

"for liver storage, one unit of vitamin A may be equal to 1% units

of carotene in oil, that is 0.9 micrograms of carotene, and that caro-
tenes in vegetables average one-third the value of carotene dissolved
in oil. Therefore, for liver storage, 2.7 micrograms of food caro-
tene instead of 0.6 micrograms, may be required to equal one unit
of vitamin A. '

The assumption that 3,000 micrograms of food carotene equal-s
5,000 units of vitamin A is, therefore, incorrect. Although 3,000
micrograms of carotene per adult might be sufficient for mainte-
nance, it may not be sufficient for good health. jones et al. (41),

l reportedithat .1_,5o0 micrograms of carotene per 10o pounds live
, weight daily allowed in most instances satisfactory feed consump-

tion and gains in fattening beef cattle, but to allow a margin of
safety, a level of 2,000 to 2,500 micrograms is recommended. This
amount of carotene is not sufficient to prevent night-blindness.

Carotene in Texas Foods

The carotene contents of some Texas foods are given in Table
12. The carotene is expressed in parts per million of the edible por-

tion of the food. The crude carotene was purified by shaking with

magnesium carbonate, but small percentages of impurity A still re-
mained with the carotene. Tomatoes and watermelon received spe-
cial treatment to remove lycopene (25). With the canned goods, the
samples were drained on cheesecloth and analysis made on the
drained solids (I). The drained solids content of some of the
samples are given in Table I3.

BULLETIN NO. 690, TEXAS AGRICULTURAL EXPERIMENT’ STATION

 
 

22
Table 12. Approxlmate carotene content of some Texas foods?»
1nd1v1dual values and averages _ r
Edible basis, Carotene parts per million
Apples.- . . . . . . . . . . . . . . . . . . . . . . . . 0.1 .1.
Apricots, canned, drained solids... 5.7, 12.8, 10.9, 10.5, 14.0, 18.7, 11.0;17.0. 14.1, 1'
Average (10) 12.8 -‘
Apricots, dried . . . . . . . . . . . . . . . . . . 42.9, 27.3, 43.1, 13.2, Average (4) 31.6
Asparagus, fresh . . . . . . . . . . . . . . . . 4.7
Asparagus, canned, green... . . . . . 6.0, 4.5, 5.4, 5. 7, 4.7, Average (5) 5.3
Avocado . . . . . . . . . . . . . . . . . . . . . . . . 1 .3
Beans, green, snap . . . . . . . . . . . . .. 3.8, 2.1, 3.4, Average (3) 3.1
Beans, green, string, canned.. . . . 3.5, 3.1, 3.4, 5.3, 2.7, 4.3, Average (6) 3.7
Beans, yellow, string, wax . . . . . .. 0.2, 0.5, 0.4, Average (3) 0.4
Beans, yellow, string, canned. . . . .' 0. 7, 0. 7, Average (2) 0.7
Beans, Lima, green, canned . . . . . . 2.6

Beets, roots, canned . . . . . . . . . . .. 0.1

Beets, tops . . . . . . . . . . . . . . . . . . . .. 25.1, 13.8, 33.0, Average (3) 23.9

Blueberries, canned . . . . . . . . . . . . . 0.2

Broccoli tips, fresh . . . . . . . . . . . . .. 6.9, 12.0, Average (2) 9.5

Cabbage . . . . . . . . . . . . . . . .  0.3,0.3,0.2, Average (3) 0.3

Cantaloupe, yellow flesh . . . . . . . .. 17.9, 11.0, Average (2) 14.5

Cantaloupe, green flesh. . . .. . . . . .
Carrots . . . . . . . . . . . . . . . . . . . . . . . . .

Carrots, canned . . . . . . . . . . . . . . . . :
Carrots, dehydrated . . . . . . . . . . . . .

Carrot juice, canned. . . . . . . . . . . ..
Carrot pomace. . . . . . . . . . . . . . . . . .
Cauliflower . . . . . . . . . . . . . . . . . . . . .
Chard, Swiss,‘ fresh . . . . . . . . .  . .
Cherries, canned
Fruit juices, 8 juices, canned. . . . .
Collards . . . . . . . . . . . . . . . . . . . . . . . .

‘ Corn, yellow, canned . . . . . . . . . . . .

Corn meal, yellow . . . . . . . . . . . . ..

Cranberries . . . . . . . . . . . . . . . . . . . . .

Cucumber . . . . . . . . . . . . . . . . . . . . . .

Dates, dried, pitted . . . . . . . . . . . . .

Endive . . . . . . . . . . . . . . . . . . . . . . . . .

Figs . . . . . . . . . . . . . . . . . . . . . .' . . . . .

Grapefruit juice . . . . . . . . . .' . . . . . . .

Hominy, yellow, canned . . . . . . . ..

Kale . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lettuce, headed . . . . . . . . . . . . . . . . .

Lettuce, loose leaf . . . . . . . . . . . . . .

Mustard greens . . . . . . . . . . . . . . . . .

Mustard greens, canned . . . . . . . ..

Okra, fresh . . . . . . . . . . . . . . . . . . . . .

Okra, canned . . . . . . . . . . . . . . . . . . .

Olives, green, canned . . . . . . . . . ..

Olives, ripe, canned . . . . . . . . . . . . .

Orange juice, canned . . . . . . . . . . . .

Parsley . . . . . . . . . . . . . . . . . . . . . . . .

Peaches, dried . . . . . . . . . . . . . . . . . .

Peaches, canned . . . . . . . . . . . . . . . .
Pea, blackeye, canned. . . . . . . . . .
Peas, English . . . . . . . . . . . . . . . . . . .
Peas, green, English, canned.....
Pepper, sweet, green. . ._ . . . . . . . . .

Pepper, red, large . . . . . . . . . . . . ..

Peppers, red, small . . . . . . . . . . . . .

Pickles, cucumber, sour . . . . . . . ..

Pickles, cucumber, sweet . . . . . . ..

Plums . . . . . . . . . . . . . . . . . . . . . . . . .

Pineapple, canned . . . . . . . . . . . . . . .

Potato, yellow, sweet . . . . . . . . . . . .

Potato, sweet, canned . . . . . . . . . ..
Potato, sweet, dehydrated . . . . . ..
Potato, sweet, dried . . . . . . . . . . . . .
Prunes, dried

Prunes, canned . . . . . . . . . . . . . . . . .
Pumpkin, raw . . . . . . . . . . . . . . . . . .
Pumpkin, canned . . . . . . . . . . . . . . .

Raspberries, canned . . . . . . . . . . . . .
Spinach, fresh . . . . . . . . . . . . . . . . . .

1.9, 1.4,0.2,0.3, Average (4) 0.9» " , ,
83,8, 40.7, 60.0, 49.8, 64.0, 106.7, 57.3, 93.3, 
104.8, 18.0, 59.5, 36.9, 106.0, 105.2, 133.1, ~’
98.0, Average (18) 74.4 f

. . , 43.6, 77.5, 62.6, Average (5) 64.4 _.
‘1048, 698, 750, 923, 855, 750, 942, 716, 231, 247;‘ i;
235, 363, 348, 424, 320, 910, 344, 733, 659, 730, 1

920, 930, 720, Average (23) 627 ‘ 3
12.3, 12.6, 21.0, 21.0, Average (4) 17.5

7 .

     
 

0.1
59.8, 33.1, 24.2, 49.0,’ Average (4) 41.5
1S0, 9.2, Average (2) 8.1
5

23.8, 45.8, 21.8, 26.0, 59.0, Average (5) 35.2
- 1.2.2.9, 2.0, 2.7, Average (4) 2.2
7.0, 2.4,4.1, Average (3) 4.5
0.2, 0.3, Average (2) 0.3

0.1

0.6

12.1, 18.0, Average (2) 15.1

0.6

.03

1.2

35.6, 35.8, Average (2) 35.7
46350.8, 1.4, 0.8, Average (4) 1.8
1

1.5
18.7, 27.8, 36.4, 19.4, 41.0, Average (5) 28.7
49.6, 26.0, 42.6, 46.8, 34.4, Average (5) 39.9

4.6,3.6, Average (2) 4.1

1.2, 1.3, Average (2) 1.3

2.8,3.l, Average (2) 3.0

1.4, 1.3, Average (2) 1.4

0.1, 0.4,0.3, Average (3), 0.3

228, 36.8, Average (2) 32.3

.2

3.4, 1.5, 1.7, 2.7, 3.0, 2.0, Average (6) 2.4
1.0

4.0,3.9,3.4, Average (3) 3.8

3.6, 4.0,3.8, 3.4, 3.8, Average (5) 3.-7_
6.4, 2.8, 1.5, 3.2, 2.3, 2.8, Average (6) 3.2
3.4.3.0, Average (2) 3.2

15.8, 9.7, Average (2) 12.8

nan-i
OHIIQ

0.3,0.5, 0.5, Average (3) 0.4
41.7, 26.6, 24.7, 36.2, 70.8, 60.0, 32.6, 31.8, 3
68.3, 50.7, 51.0, 38.1, 58.2, 38.2, 20.2, 45.0, 505
64.2, 80.0, Average (20) 48.5 ,-

46.5 --

131, 126, 143, 134, 132, 160, 156, 88, Average (8) 134 .

61.5, 27.0, 27.4, Average (3) 38.2 ~f

1.3

12.8

20.0 f

37.4, 42.0, 38.4, 55.4, 56.5, 38.0, 49.2, 21.1, 14‘
Average (9) 39.1 I

a,

1.2 ._
45.0, 42.0, 36.0, 30.5, 61.5, 67.6, 46.0, 30.0, Av
(8) 44.8 ‘7

  

VITAMIN A AND CAROTENE 1N HUMAN FOODS I A i i u 

Table 12. Approximate carotene content of some Texas foods,
individual values and averages-Continued

Edible basis, Carotene parts per million

Spinach, canned . . . . . . . . . . . .. .. 60.2, 46.0, 50.0, 60.2, 61.4, 68.6, 47.4, 45.4, 54.0,
, 33.1, 70.2, 58.0, Average (12) 54.5 _;
Squash, white flesh . . . . . . . . . . . . . 0.2, 0.2, 0.4, 2.0, 4.0, Average (5) 1.4

Squash, yellow flesh....... . . . . .. 5.0, 8.4, Average (2) 6.7

Strawberries, canned . . . . . . . . . . . . 0.3

Tomatoes . . . . . . . . . . . . . . . . . . . . .. 8.0,2.2,2.4, 1l.1,6.5, Average (5) 6.0

Tomatoes, canned . . . . . . . . . . . . . .. 7.3, 9.4, Average (2) 8.4

‘ Tomato juice, canned . . . . . . . . . .. 5.6, 3.9, Average (2) 4.8

1 Turnip greens . . . . . . . . . . . . . . . . .. 24.5, 21.2, 31.2, 43.9, 20.2, 32.0, 46.4, 72.0, 76.1,
f - 80.6, 60.2, 42.8, 54.1, 49.0, 19.0, Average (15)
' 44.9
Turnip greens, canned. . . .. . . . . . . 43.9, 54.4, 30.0, 42.4, 41.4, 35.6, 35.2, 40.1, 74.2, 39.0,
Average (10) 43.6
Watermelon, edible part . . . . . . . .. 6.8, 6.0, 2.4, Average (3) 5.1

   
  
   
  
  
 
 

Wide differences are found between the carotehe content of dif-
ferent samples of the same food (Table 12). For example, the caro-
tene content of canned peaches, drained solids, ranges from 5.7 to
18.7 parts per million ;- that of dried apricots, from 13.2 to 43.1,
and that of carrots from 18.0 to 133.1. It has been pointed out that
there were even wide differences in the vitamin A content of the
livers of the same kind of animals fed for the same period of time
on the saime feeds.

In formulating diets, allowances must, therefore, be made for
variations in foods.

Table 13. Percentage of drained solids in canned goods

Apricots, 61, 62, average 62.

Asparagus, 69, 59, average 64.

Beans, Lima, 65.

Beans, wax, yellow, 53.

Beans, green, stringless, 67, 53, average 60.
Carrots, 56. 58, average 57.

Corn, yellow, 100, 59, average 80.
Mustard greens, 57, 51, 63, average 54.
Okra, 61, 82, average 72.

Peaches, 58, 47, average 53.

Peas, English, 58, 65, 68, average 64.
Pineapples, 84, 58, average 71.
Pumpkin, 100, 100.

Spinach, 84, 55, 60, average 66.
Tomatoes, 38, 35, average 37.

Turnip greens, 56, 74, 51, average 60.

No attempt has been made to compile the analyses for carotene
 and vitamin A reported in the literature. Average values of eleven
nutrients in foods, including vitamin A and other vitamins, are
 presented in reference 6. The vitamin A values of 128 foods as de-
 termined by the rat-growth method are given by Booher and Marsh
§  The carotene values of some canned foods have been given by
fPressby et al. (53), and by Guerrant et al. (36).

2_4 BULLETIN NO. 690, TEXAS AGRICULTURAL EXPERIMENT STATION

Vitamin A and Carotene per Pound of Edible Parts of Foods and of 

Foods as Purchased

The approximate number of units 0f vitamin A per pound of j
foods from animal sources, and the number pounds of foods required
to furnish 5,000 units (the daily requirement for an adult human)
are given in Table I4. Variations in the natural foods have already
been discussed. The value of any carotene present is included in the i

units of vitamin A.

Table 14. Approximate vitamin A content of some foods of animal origin 

' Assumed '
Edible part, cost per Cost of ,
units Pounds per pound as 5,000 units,
per pound 5,000 units purchased, cents ~

cents
Butter . . . . . . .‘ . . . . . . . . . . . . . . . . . . . . 15.000 .33 60 19.8 _

Cheese, Cheddar . . . . . . . . . . . . . . . . . 8,000 .62 50 31.0

-»Cheese, cottage . . . . . . . . . . . . . . . . . . . 100 , 50.00 40 2000.

Cheese, cream . . . . . . . . . . . .' . . . . . . . . 9,000 ' .55 50 27.5

Cheese, all other . . . . . . . . . . . . . . . .. 8,000 .62 60 37.2

Eggs, whole. .. . . . . . . . . . . . . . . . . . .. 4,500 1.11 35 38.9

_Liver,. beef. . .‘ ._ . . . . . . . . . . . . . . . . . .. 30,000 . 17 _ 60 10.2

Liver, calf... . . . . . . . . . . . . . . . . . . . .. 10,000 .50 50 ' 25.0

Margarine, fortified. . . . .' . . . . . . . . . . 9,000 .55 40 22.0

Margarine, fortified . . . . . . . . . . . . . . . 15,000 .33 40 ‘ 13.2

Milk, whole . . . . . . . . . . . . . . . . . . . . .. 700 7.14 I ll 78.5

The approximate average amount 0f carotenes in micrograms per ‘

ound of the edible ortions of human foods are iven in Table I . _

P P _ g _ _
As pointed out on preceding pages, the carotenes usually include

two or more carotenes, and the beta-carotene potency of the total
carotenes is less than that of pure beta-carotene (Table 6). The esti-

mated edible part of the foods as purchased is also given in Table .

15. This differs with the quality of the food, the method of harvest,
and the severity of trimming in the kitchen. With canned goods, the
percentages of drained solids are given because our analyses for caro-
tene were made on the drained solids. The approximate carotene con-
tent, in micrograms of carotene per pound as purchased, given in the
third column of Table I5, was calculated from the data in the.first

two columns. From these data, and those in Table I4, it is possible to _

calculate the approximate carotene content of» these foods as pur-
chased for the family diet, so the purchases can be supplemented if

necessary. The pounds of food, as purchased, which will contain -
. 5,000 micrograms of carotene, assumed to be the requirement for ,

an adult, is given in the fourth column of Table I5.

The daily requirement is furnished by less than a pound of the 
food as purchased, and still less ‘in the edible portions, of such foods f

,V‘"P_W7vv—w~ v~s.,m.-.e._.,._wnw-rw..w I

"Hr-h.-  .1-..“ WWW’) Ww.,_,-_w.-_.....-. _-.._.,.. ..

VITAMIN A AND CAROTENE IN HUMAN FOODS

25

as dried apricots, carrots, chard, collards, kale, mustard greens,
dried peaches, [sweet potatoes, yellow pumpkin, squash and turnip
greens. Many other foods contain so little carotene that, while they

Table 15. Approximate carotene content of some foods of vegetable origin,
and cost of 5000 micrograms

Edible As Pounds Assumed Cost of

part, Edible purchased as cost as 5000
carotene part carotene purchased purchased micrograms
micrograms 0 micrograms per 5000 cents per of carotene,

per pound per pound micrograms pound cents

Apples, fresh . . . . . . . . . . . . . . . . 45 88 40 1Z5. 15 1875

Apples, dried . . . . . . . . . . . . . . . . 180 100 180 27.8 50 1390

Apricots, fresh . . . . . . . . . . . . . . . 5000 94 4600 1.1 15 17

Apricots, dried . . . . . . . . . . . . . . . 11000 100 11000 .45 ' 50 Z3

Apricots, canned . . . . . . . . . . . . . 5400 162* 3300 1.50 Z0 30

Asparagus, green . . . . . . . . . . . . . Z200 75 1650 3. 0 Z5 75
Asparagus, green, canned. . . . . 2200 64* 1400 3.6 35 121
Asparagus, yellow, canned. . . . . 900 64* 580 8.6 35 301

vocado, fresh . . . . . . . . . . . . . . . 450 75 330 15.0 50 750
Banana, fresh . . . . . . . . . . . . . . . . 540 70 380 13.2 15 198
Beans, snap, green . . . . . . . . . . . 1300 90 1170 4.3 Z0 86
Beans, snap, yellow . . . . . . . . . . . 180 90 160 31.2 Z0 62
Beans, snap, green, canned. _ . 1500 60* 900 5.5 Z2 111
Beans, snap, yellow, canned. _ _ 310 60* 180 27.2 22 599
Beans, Lima, green, canned. . . 1100 70 770 6.5 Z5 162
Beets, tops, fresh . . . . . . . . . . . . 10400 Z5 Z600 1.9 Z0 38

Beets, tubers, fresh . . . . . . . . . . 45 75 33 151.5 Z0 3030

Broccoli fresh . . . . . . . . . . . . . .. 4000 60 Z400 Z.1 Z5 53

Cabbage . . . . . . . . . . . . . . . . . . . . 130 70 90 55.5 6 333

Cantaloupe, yellow flesh . . . . . . . 5300 40 Z100 2.4 10 Z4

Cantaloupe, green flesh . . . . . . . 450 40 180 27.2 10 Z7Z

Carrots, fresh . . . . . . . . . . . . . . . . 31800 60 19000 .26 7 1.8

Carrots, canned . . . . . . . . . . . . . . 29000 57* 16500 .30 12 3.6

Carrot juice, canned . . . . . . . . 7700 100 7700 .65 15 9.8

Chard, Swiss, fresh . . . . . _ . . . . _ 18000 86 15400 .32 10 3.2

Cherries, canned . . . . . . . . . , . . 3800 60* Z160 2.3 Z0 40

Collards, fresh . . . . . . . . . . . . . . . 16000 50 8000 .63 10 6. 3
Corn, fresh, yellow (on cob) . . 900 Z0 180 27.2 5 130
Corn, yellow, canned . . . . . . . . . . 900 80* 7Z0 7.0 Z0 140

Corn meal, yellow . . . . . . . . . . . . 1000 100 1000 5.0 15 75

Cranberry . . . . . . . . . . . . . . . . . . 135 90 1Z0 41 .7 Z5 1043

lgs . . . . . . . . . . . . . . . . . . . . . . . Z70 90 Z40 20.8 10 Z08

Kale . . . . . . . . . . . . . . . . . . _ . . . . . 13500 70 9450 .53 10 5.3

Lettuce, heads, yellow . . . . . . . 800 70 560 9.0 15 135

Lettuce, loose leaf, green . , . . . . 4500 70 3150 1.6 15 Z4

Mustard greens . . . . . . . . . . . . . . 12700 70 8900 .56 l0 5,0

Mustard greens, canned . . . . . . 17200 54"‘ 9300 .54 15 3,1

Okra, fresh . . . . . . . . . . . . . . . . . . 1800 9) 1600 3. 1 Z0 62

Okra, canned . . . . . . . . . . . . . . . . 590 72* 4Z0 12.0 Z0 Z40

Olives, green . . . . . . . . . . . . . . . 1360 80 1070 ' 4.6 90 414

Olives, ripe . . . . . . . . . . . . . . . . . . 450 80 360 13.9 85 1182

Orange juice, canned . . . . . . . . 130 100 130 38.0 10 330

Orange, w ole . . . . . . . . . . . . . . . 130 40 50 100 5 500

Peaches, dried . . . . . . . . . . . . . . . 5400 100 5400 .93 . 50 45

Peaches, fresh . . . . . . . . _ . . . . . . 1800 88 1600 3. 1 8 Z5

Peaches, canned . . . . . . . . . . . . . 1360 53* 700 7. 1 Z0 142
Peas, English, fresh (in pods) . . 1600 45 720 7.0 Z0 140
Peas, English, canned . . . . . . . . . 1600 64* 1020 4.9 Z0 98

Peas, green, dried . . . . . . . . . . . . 3180 100 3180 1.6 Z0 3Z

Pepper, sweet, green . . . . . . . . . . 1360 84 1000 5.0 Z0 100

Pickles, cucumber . . . . . . . . . . . . 450 100 450 11.1 30 333

Pineapple, canned . . . . . . . . . . . . 180 71* 140 35. 7 30 1071
Potatoes, sweet, yellow, fresh. . Z0400 88 17500 .28 8 -3
Potatoes, sweet, dehydrated. . . 59000 100 59000 .08 . . . . . . . . . . . . - - . . - . - . - - - -
Prunes, drie . . . . . . . . . . . . . . . . 450 85 380 13.2 Z0 Z64
Pumpkin, yellow, fresh. . . . . . . . 9000 70 ‘ 6300 .8 10 3
Pumpkin, canned . . . . . . . . . . . . . 17500 100 17500 .29 14 4

Spinach, fresh . . . . . . . . . . . . . . . . 18000 80 14400 .35 15 5-3

Spinach, canned . . . . . . . . . . . . . 22500 66" 14600 .34 Z0 0-0

Squash, white flesh . . . . . . . . . . . 450 70 310 16.0 5 30

Squash, yellow flesh . . . . . . . . . . Z700 70 1890 2.6 5 13

Tomatoes, fresh . . . . . . . . . . . . . . 2700 88 Z380 Z.1 15 32

Tomatoes, canned . . . . . . . . . . . 2700 37* 1000 5.0 14 70

Tomato juice, canned . . . . . . . . . Z000 100 Z000 2.5 14 35

Turnip greens, fresh . . . . . . . . . . 18000 84 15000 .33 10 3-3

Turnip greens, canned . . . . . . . . 18000 60‘ 10800 .46 10 4-0

Watermelon . . . . . . . . . . . . . . . . . Z200 40 880 5.7 3 17

‘drained solids

26 BULLETIN NO. 690, TPEXAS AGRICULTURAL EXPERIMENT STATION

add some carotene .to the diet, such contribution can be considered

as only incidental to their other food values. It would take more r

5,000 micrograms of carotene from such foods as apples, avocado,
yellow snap beans, beet tubers, cabbage, green-flesh cantaloupes,
fresh yellow corn on cob, cranberry, figs or white-fleshed squash.

- than IO pounds of food as purchased to meet the requirements of '

. ...-\-lili_lr.nufldl

These foods have other nutritive values, but rank low in carotene 

content. Still other foods have intermediate carotene values.

Relative Cost of Vitamin A Potency in Foods

A few human foods, such as sugar or starch, furnish only one j

nutrient, but almost all foods furnish two or more nutrients. Many

contain IO or more nutrients (6). This makes it very difiicult to _

calculate the actual cost of any one nutrient. Some foods have rela-

tively high contents of vitamin A or carotene, some moderate a
amounts, and others contain practically none (Table 12). It would
be very difficult to calculate the cost of the various nutrients in hu- ‘

man foods, if all of them are considered. It is possible, approximate-

ly, to compare the relative costs of carotene and vitamin A in human F
foods by disregarding the other nutrients, but these other values ;
should never be entirely forgotten in considering such foods. Vita- ~

mins can also be secured in concentrated forms, both as single vita-
mins or as mixtures. These are included in the comparisons here
made.

A survey made in December, 1941 (27), showed that mustard
greens was the cheapest source of vitamin A potency, followed by
turnip greens, sweet potatoes, carrots, spinach and beet tops, in the

order given, followed by other foods not here listed. A similar sur-w

vey made in July, I941 (29), gave fresh pumpkin as the cheapest
source of carotene followed by sweet potatoes, collards, carrots, yel-
low cantaloup, mustard greens, turnip greens, Swiss chard and wa-
termelon, and then others. A survey for carotene, energy, proteins

and vitamin C was published in 1943 (1 1). Another survey in April, I

1944 (19), showed fresh carrots to be the cheapest source of vitamin
A potency at that time, followed by sweet potatoes, spinach, mus-
tard greens, turnip greens, pepper, and then others. The relative
costs of carotene in vegetables depend to some extent upon the sea—
son of the year, the vegetables locally grown being cheaper when in
season than these vegetables shipped from a distance.

The surveys cited above do not include canned goods. A survey
made in April, 1942 (28), gave pumpkin as the cheapest source of
carotene in canned goods at that time, followed by carrots, spinach,

VITAMIN A AND CAROTENE IN HUMAN Foons" e 27

turnip greens, mustarldigreens, ‘carrot juice, apricots, and others not
here listed. The fresh vegetables, when available, were usually
cheaper sources of carotene than the canned goods, but there were
canned vegetables which furnished vitamin A potency at. reasonable
prices. . - '
For the purpose of this bulletin, the selling prices of various ‘foods
were collected at‘ College Station, Texas, and supplemented "by
prices advertised in the Bryan and Houston papers. For some foods
not available, prices were assumed. The approximate price per pound
i was multiplied by the number of pounds of food as purchased as
* needed to contain 5,000 units of ‘vitamin A or of carotene, per
Tables 14-15. i

p The least expensive sources of carotenes (Table 15) arein the
 following order: carrots least (1.8 cents for 5,000 micrograms),
sweet potatoes, (2.3), chard (3.2), turnip greens‘ (3.3), carrots,
canned (3.6), pumpkin, canned (4), turnip greens, canned (4.6).
‘kale (5.3), mustard  spinach (5.3), spinach, canned (6.8),
Epumpkin, yellow fresh ('8). and carrot juice (9.8 cents per 5,000
i micrograms).

.5

F

swmvv. ,__c‘___._. ,_,..

   
 
  
 
   
 
 
 
  
  
   
  
 

Vitamin A in foods of animal origin is more expensive than caro-
tene. Liver furnishes vitamin A at the lowest price, nearly 10.2

pound comes next (15.2 cents), butter (19.8), margarine with 9,000
iinits (22), calf liver (25), cream cheese (27.5), cheddar cheese
(31), and eggs (38.9 cents per 5,000 micrograms). All these foods
Tcontain other desirable nutrients. ' i i

i  Food prices in differentcities are collected regularly by the U. ‘S.
15Bureau of Labor Statistics (7), and supplementary information on
,prices may be obtained from them.

i , Vitamin A may also be secured in capsules or pills. Vitamin A
7and D capsules containing 5,000 units, can be secured at 0.7-1.0
cents each, halibut liver oil for about 1 cent per 5,000 units, and
icod liver oil, 2 capsules with 2,500 units each, for 2.2 to 2.5 cents‘.
‘Some complex vitamin-capsules, containing 5,000 units of vitamin
A with other vitamins such as vitamin D, vitamin C, thiamin, ribo-
‘ijhvin, niacin amide and vitamin E, can be secured for 1.5 "to 4 cents
f r 5,000 units of vitamin A. These prices compare favorably with
givitamin A costs in vegetables and other foods, and such capsules
gmay be used for. supplementary purposes. It is most desirable, how-
fever, to secure the vitamins needed from foods, especially because
i, l the vitamins have not yet been identified.

cents for 5,000 units. Margarine fortified with 15,000 units per _

28 BULLETIN NO. 690, TEXAS AGRICULTURAL EXPERIMENT STATION

Balancing the Diet in Vitamin A Potency

The daily diet, or the purchases of food for the family in weekly
0r other intervals, may be compared with the recommendations, and
improved as may be desirable. By using the data in reference 6,
the probable content of the diet in calories, proteins, minerals and
vitamins can be calculated. '

An example of a low-cost diet, which would contain approximate-
ly all required nutrients, is given by the Committee on Food and
Nutrition of the National Research Council (Io). This diet fur-
nishes the recommended allowance for nutrients for a moderately
active man for one day, The data are given in Table 16, and the
carotene and vitamin A content were calculated from the data in
Tables I4 and I5. The calculations show that this diet provides
much more than the 5,000 units of vitamin A potency which is rec-
ommended. The effect of substituting other foods containing vita-
min A or carotene can easily be ascertained.

A supply of food planned on a weekly basis to provide a good

diet, and provides for a greater variety of foods. Practically, a
week may be too long a period for pre-planning menus.

Table I7 contains an example of a weekly food basket for a mod-
erately active man, his wife and two children, son, age 9 and daugh-
ter, age 7, based on the standard budget of the Dallas Council of
Social Agencies, and used by the U. S. Bureau of Labor Statistics
(8). The vitamin ,A recommended for such a family is calculated
from data in Table 11 to be 119,000 units. As shown in Table 17,
the quantities of vitamin A and carotene in the foods in question
would fall below this recommendation even if 0.6 micrograms of

Table 16. Approximate vitamin A and carotene content of food for
one man one day (10)

‘diet has the advantage of requiring less calculation than a daily_

Amount Vitamin A Carotene
pounds units micrograms
Milk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l .0 700 . . . . . . . . _ . _ .

Meat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 0 . . . . . . . . . . . .

Potatoes, Irish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 0 . . . . . . . . . . .

Baked beans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . I .44 0 . . . . . . . . . . , .

Cabbage, raw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . .20 . . . . . . . . . . . . 26

Carrots (edible part) . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 . . . . . . . . . . . . 6360

Tomatoes (edible part) . . . . . . . . . . . . . . . . . . . . . . . . . .40 . . . . . . . . . . . . 1080

Prunes, stewed (edible part) . . . . . . . . . . . . . . . . . . . . .40 . . . . . . . . . . . . I80

Margarine (15,000 units) . . . . . . . . . . . . . . . . . . . . . . . . . l5 2250 . . . . . . . . . . ..

Oatmeal, cooked. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70 0 . . . . . . . . . . . .

Bread, whole wheat or enriched . . . . . . . . . . . . . . . . . .40 0 . . . . . . . . . . . .

Gingerbread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 0 . . . . . . . . . . . .

Sugar or jam . . . . . . . . . . . . . .' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0_ . . . . . . . . . . . . f

Total . . . . . . . . . . . . . . . . .- . . . . . . . . . . . . . .' . . . . . . . . . . . . . . . . 2950 7886 " ‘i

Recommended amount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5000

..i._2__a..._. ,_. nuamlnh...“ .1, 

VITAMIBN A AND CAROTENE IN HUMAN FOODS '6 I 29

Table 17., Vitamin A and carotene content of foods for basket believed
suflicient for one week for a man, his wife andtwo children,

9 and 7 years old respectively (8) .
Amount Vitamin A Carotene
pounds units micrograms
Milk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a 32 22,400 . . . . . . . . . . . .

Eggs (2 dozen) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3 13,500 . . . . . . . . . . . .

Butter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 15,000 . . . . . . . . . . . .

Oleomargarine (15,000 units) . . . . . . . . . . . . . . . . . . . . l 15,000 . . . . . . . . . . . .

Lard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . 1 0 . . . . . . . . . . . .

Bacon. sliced . . . . . _ . . . . . . . . . . . . . _ . . . . . . . . . . . . l 0 . . . . . . . . . . . .

Steak. round . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0 . . . . . . . . . . . .

Roast, chuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 0 . . . - . . . . . . . . .

‘Chicken, roasting . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . 3 0 . . . . . . . . . . . .

Potatoes, white . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 0 . . . . . . . . . . . .

Bread, white . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . . . . 7 0 . . . . . . . . . . . .

Flour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 0 . . . . . . . . . . . .

Cornflakes . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . .  . l 0 . . . . . . . _ . . . .

Oats, rolled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 0 . . . . . . . . . _ . .

(‘abbage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . 5 . . .' . . . . . . . . . 450

Peas, canned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 . . . . . . . . . . . . 4050

Onions . . . . . . . . . . . .- . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . . . . . . . . . . . . ' 0

Beans, snap, canned _ . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . . . .' . . . . . . . . 4500

Tomatoes, canned . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . 6 . . . . . . . . . . . . 6000

Banana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . . . . . . . . .\._. . 1900

Oranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 . . . . . . . . . . . . 350

Prunes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 .5 . . . . . . . . . . . . 570

Beans, navy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . . . . 0

(‘oifee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l . . . . . . . . . . . . 0

Sugar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . . . . . . . . . . . . 0

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . 65 , 900 l 7 , 850

Grand total . . . . . . . . . . . . . . . ._ . . . . . . . . . . . . . . . . . . . . . . . . . 83,750

Requirements . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119,000
Table 18. Approximate vitamin A and carotene content of food ,for
6 adults for 7 days (61)

Edible -
portion, Vitamin A Carotene
pounds units micrograms

Milk, skim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. so 7 _ . . . . . . . . . . . . . . . . . . . . . . ..

, g8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 . 0 18 , 000 . . . . . . . . . . . .

c Meat, assorted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.0 . . . . . . . . . . . . . . . . . . . . . . . .

, Peanuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.8 . . . . . . . . . . . . . . . . . . . . . . . .

~ Lard . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . l .2 . . . . . . . . . . . . . . . . . . . . . . . .

Margarine (15,000 units) . . . . . . . . . . . . . . . . . . . . . . . . 3.4 ' 51 .000 . . . . . . . . . . . .

Rice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0. 7 . . . . . . . . . . . . . . . . . . . . . . . .

K Flour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l3. 6 . . . . . . . . . . . . . . . . . . . . . . . .

Corn meal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 . . . . . . . . . . . . . . . . . . . . . . . .-

Oats. rolled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 . . . . . . . . . . . . . . . . . . . . . . . .

Potatoes, white . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4 . . . . . . . . . . . . . . . . . . . . . . . .

Potatoes, sweet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4 . . . . . . . . . . . . 89,700

Beans, Lima . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 . . . . . . . . . . . . . . . . . . . . . . . .

Onions, old . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0. 8 . . . . . . . . . . . . . . . . . . . . . . . .

Onions, green . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0. l . . . . . . . . . . . . . . . . . . . . . . . .

Carrots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. 2 . . . . . . . . . . . . 133,500

Turnips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l .5 . . . . . . . . . . . . . . . . . . . . . . . .

Beet roots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.0 . . . . . . . . . . .. 135

Beet tops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.8 . . . . . . . . . . .. 18,720

j Cabbage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.2 . . . . . . . . . . .. 416 '

, Swiss chard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2.2 . . . . . . . . . . .. 39,000

. Lettuce, head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0. 5 . . . . . . . . . . . . 400

_' Tomatoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 . . . . . . . . . . . . 4,050

Apples, dried . . . . . . . . . . . . . .  . . . . . . . . .. 1.9 . . . . . . . . . . .. .210

' ns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 .4 . . . . . . . . . . . . . . . . . . . . . . .

Grapefruit . . . .  . . . . . . . . . . . . . . .  . . . . . . . . .. 3.1 . . . . . . . .  . . . . . . . . . ..".

Oranses  . . . . . . . . . . . . . . . . . . . . . . . . . .  3.7 . . . . . . . - . . .- 480

Sugar . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . .. 3.0 . . . . . . . . . . . . . . . . . . . . 

Sorghum syrup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 . . . . . . . . . . . . . . . . . . . . . . . .

Total . . . . . . . . . . . . . .  . . . . . . . . . . . . . . . . . . . . . . . ........ 69,000 286,671
. i - a

30 BULLETIN NO. 690, TEXAS AGRICULTURAL EXPERIMENT STATION

carotene is taken to equal 1 unit of vitamin ~A potency. The additi. l
of 2 pounds of carrots, chard or spinach, or 3 pounds of mus . _
greens per week, would bring the diet practically up to the reco ~;i__
mendation for vitamin A potency. I’

Table 18 contains a low-cost, tested diet for 6 adults, 7 day

t‘
a

calculated from diet No. 7 of Whitacre (61). The carotene and vi 
min A units calculated for 6 adults for 7 days would be 210, Q‘
units, and that calculated from the data in Tables 1o and II wou 
be 69,000 units of vitamin A plus 286,671 micrograms of ‘carote

=.

showing that sufficient quantities of vitamin A are provided. .

A Acknowledgment

  

Grateful acknowledgment is made to A. R. Kemmerer, W.  
Meinke and Jeanne De Mottier for analytical and other work ' 
cluded in this bulletin. if

Summary



Vitamin A is one of the many vitamins which, in addition 
energy, protein and minerals, must be present in suitable amount
for an adequate human diet. Carotenes are converted to vitamin 
during the process of digestion. Methods used for the determi 
tions of vitamin A potency, vitamin A and carotenes are briefl
described. - j;

Carotene consumed in feeds is converted to vitamin A, which 
used primarily for maintenance and in animal products such 
eggs or milk, but any excess may be stored in the body, chiefly {l
the liver. ‘ - 

Variations in the vitamin A content of livers, butter, milk an
eggs are discussed. The amount of vitamin A present depends u i?
the carotene or vitamin A content of the feed the animal is receivj,’
ing and the amounts of vitamin A stored in the liver. Livers fro
steers depleted of vitamin A and fed food containing low amount
of vitamin A may contain only 3 to 9 units of vitamin A per gramfYT
Beef livers purchased in Bryan and College Station contained fr .5
24 to 1,062 units of vitamin A per gram. r

Vitamin A potency of chicken livers was related to the car
tene content of the diet fed. Livers of different animals on the sa 1'
feed sometimes differ appreciably. ' ' 

The vitamin A content of butter soldin 'l‘exas ranged from 20- 
to _52.6 units per. gram, with an average for the year of 37 uni;
per gram, which is 16,798 units per pound. A » - 4

The carotene content of yellow corn is related to the number y
genes for yellow color, 1,‘ 2 or 3.’ ‘i i i A 1 

    

sf

    
   
   
  
   
   
   
 
   
    
 
   
  
  
 
  
   
 
   
  
  
  
    
  
  

VITAMIN A AND CAROTENE IN HUMAN FOODS 31

>-Carotenes in foods are mixtures. Raw leafy vegetables average
6 percent beta-carotene, I0 percent neo-beta-carotene U and 8 per-
i nt neo-beta-carotene B. Cooking leafy vegetables increased the
eo-beta-carotene from 8 to 18 percent, the neo-beta-carotene U from
10 to 13 percent, and decreased the beta-carotene from 76 to 63 per-
int of “the total carotenes, thereby decreasing the value of the caro-
tenes for vitamin A production. Alpha-carotene is also present in
5 rrots and pumpkins. Corn contains cryptoxanthin as well as beta-
" rotene, but the separation of all the carotenes in corn‘ remains to
 made.

.6 When 2o micrograms of crude carotene per day were fed, the
_'gestibility of beta-carotene by rats ranged in I7 tests from 8 per-
gnt with boiled carrots to 55 percent with boiled mustard greens,
H‘ d averaged 44 per cent with the greens and 32 percent with the
A er vegetables. Other digestion tests are cited. '
 Carotenes fed rats at low levels sufficient for maintenance and
ight growth, had a relative average vitamin A potency of 93, with
f‘ otene in oil taken to be I00.

V. The storage of vitamin A in the livers of rats in r9 tests on 6
in! ranged from 16 to 64 percent of that of carotene in oil,’ with
 average of 32 percent. Addition of oil to the diet improved the
tilization of carotene. I
Qlnsufficient vitamin A in the ration decreases the length of life
H rats, and also reduces-the number of litters, the number of young,
 percentages born alive and the live weights of_ the young rats
_ the time of weaning. .

The human requirements for vitamin A and carotene are dis-
psed.

ijThe carotene contents of Texas foods, and the average vitamin
-. and carotene content of the edible parts of foods and of the foods
 purchased, are given. ‘ i a

‘The cost of 5,000 units of vitamin A and of 5,000 micrograms
i, otene in human foods are discussed. The lowest costing foods
31nd on the season. The least expensive in June, I947, were car-
s, fresh (least), sweet potatoes, chard, turnip greens, carrots
 ned), pumpkin (canned), turnip greens (canned), kale, mus-
1 d, spinach (fresh), spinach (canned), pumpkin, yellow fresh,
 carrot juice (most expensive). Vitamin A ofanimal origin is
re expensive than carotene. ' '

p _ion_s arevgmade to improve the diet in this respect.

“Balancing the diet in vitamin  potency is discussed, and sug»

32

94
q

6.

IO.
II.

12.
13.
14.

~15.

16..

18.

19.
2o.

2X.

rFraps, G. S., 1933. Vitamin A content of foods and feeds. Texas A

‘cryptoxanthin in yellowcorn. Ind. Eng. Chem. Anal. Ed. 113:8o6-8'

BULLETIN NO. 690. TEXAS AGRICULTURAL EXPERIMENT STATION

 
 
  
  
   
  
  
   
   
      
  
   
   
  
   
 
   
   
   

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u;
-_.

1943. Nutrition and Visi

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Federal Security Administration, 1941. Label statements concerni
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mended dietary allowances. Reprint and Circular Series. National '.
search Council. No. 115. Revised 1945, No. 122. ’ 

Fraps, G. S., 1942. Relative cost of energy, protein, vitamin C 
carotene in human foods. Texas Acad. Sci. Proceedings and Tran 
tions, 1942. » 
Exp. sm. Bul. 477. . 
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carotene by the white rat. Archives Biochem. 10:485-489.

F raps, G. S., 1946. Composition, digestibility and energy values of so“
human foods. Texas Agr. Exp. Sta. Bul. 68o. A 
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Biochem. 13:295. ‘i
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stuffs. Texas Agr. Exp. Sta. Bul. 461. Revised. 
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VITAMIN A AND CAROTENE IN HUMAN FOODS 88

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of crude carotene of plant extracts. lnd. 8a Eng. Chem. 38:457-458.

Fraps, G. S., A. R. Kemmerer and S. M. Greenberg, I940. The estima-
tion of units of vitamin I) and vitamin A in fish liver oils and their con-
centrates. Jour. Assn. Official Agr. Chem. 23:417-422.

Fraps, G. S., A. R. Kemmerer and S. M. Greenberg, I940. Determination
of carotene in presence of lycopene. Jour. Assn. Ofiicial Agr. Chem. 23:
422-425.

Fraps, G. 5., W. W. Meinke and A. R. Kemmerer, I941. Determination
of pure carotene in green vegetables and green feeds. Jour. Assn. Ofiicial
_Agr. Chem. 24:739-744.

Fraps, G. S. and Meinke, W. W., I942. Economical sources of vitamin
A potency in human foods. Texas Agr. Exp. Sta. Progress Report 764.
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A potency in canned goods. Texas Agr. Exp. Sta. Progress Report 785.
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A potency in human foods. Texas Agr. Exp. Sta. Progress Report 791.
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A in liver. Jour. Assn. Official Agr. Chem. 26:399-404.

Fraps, G. S. and W. W’. Meinke, I945. Relative values of carotenes in
foods as measured by storage of vitamin A in livers of rats. Food Re-
search 10:187-196. g

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beta and neo-beta-calrotenes in vegetables. Archives Biochem. 6:323-327.
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in dried foods. Ind. and Eng. Chem. 25:465-471.‘

Fraps, G. S. and Ray Treichler, I933. Losses of vitamin A in drying
fresh raw carrots and sweet potatoes and canned spinach. Jour. Agr. Re-
search 47:539-541.

Frapis, G. 5., Ray Treichler and A. R. Kemmerer, I936. Relation of
the carotene content of certain feed materials to their vitamin A potency.
Jour. Agr. Research 53:713-716.

Guerrant, N. 13., M. G. Vavich, O. B. Fardig, R. A. Dutcher and R. M.
Stern, 1946. Changes in the vitamin content of foods during canning.
Jour. Nut. 32:435-458.

Hale, F. I933. Pigs born without eyeballs. Jour. Heredity 24:105.
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mia in pigs. Texas State J. Med. 33:228. .

Jones, D. 13., G. S. Fraps, B. H. Thomas and L. Zeleny, 1943. The effect
of storage of grains on their nutritive value. National Research Council.
Reprint and Circular Series No. I I6.

Jones, J. H., J. M. Jones, G. S. Fraps, A. R. Kemmerer, R. E. Dickson, I

C. E. Fisher and N. R. Ellis, I944. Sorghum silages and dehydrated
alfalfa leaf meal as sources of carotene in beef cattle fattening rations.
Texas Agr. Exp. Sta. Bu]. 659.

Jones, J. H., H. Schmidt, R. E. Dickson, G. S. Fraps, J. M. Jones,
J. K. Biggs, A. R. Kemmerer, P. E. Howe, W. H. Black, N. B. Ellis and
P. T. Marion. I943. Vitamin A studies in fattening feeder calves and
yearlings. Texas Agr. Exp. Sta. Bul. 630.

Kemmerer, A. R. I946. Report of Associate referee on carotene. Jour.
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34

43-
44-
45-

46.
'47-
48.
49-

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53-
54-

55-

56.

57-

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6o.

61.

   
  
   
  
   
  
 
  
    
 
 
  
  
   
  
 
 
  
  
 
  
   

BULLETIN NOY690, TEXAS AGRICULTURAL EXPERIMENT STATION

Kemmerer, "A. R. and G. S." Fraps. 1943. The vitami-n A content of t“
mercial butters sold in Texas. Texas Agr. Exp. Sta. Bul. 629." i
Kemmerer, A. R. and G. S. Fraps. 1943. Constituents of carotene ext p
of plants. Ind. and Eng. Chem, Anal. Ed. 15:714-716. '_
Kemmerer, A. R. and G. S. F raps. 194 5. Relative value of carotene"
vegetables for growth of the white _rat. Archives Biochem. 81197-201 g
Kemmerer, A. R. and G. S. Fraps. 1945. Constituents of the crude w;
tene of carrots. Food Research 10:457-460. 5

Kemmerer, A..R. and G. S. F raps. The vitamin A activity of neo-
carotene U and its steric rearrangement in the digestive tract of 8
Jour. Biol. Chem." 161 :3o7-3o9.: , - i
Kemmerer, ‘A. R., G. S. F raps, and Jeanne De Mottier, 1947. Effect:
xanthophylls, chlorophylls, sulfasuxidine and alpha-tocopherol on

utilization of carotene by rats. Archives Biochem. 12:135-138. i
Kemmerer, A. R., G. S. Fraps and P. C. Manglesdorf, 1942. The 
tion between the vitamin A active carotenoids in corn and the number
genes for yellow color. Cereal Chemistry 19 :52 5-528. f
Kemmerer, A. R., G. S. Fraps and W. W. Meinke, 1945. Constituen
the crude carotene of certain human foods. Food Research 10:66-71.  
Manglesdorf, P. C. and G. S. Fraps, 1931. A direct quantitative.
lationship between vitamin A in corn and the number of genes ,_
yellow pigmentation. Science 73:241-242. S
Novaes, J. L. 1939. Hora Medico 11 :84. 
Pressley, Anne, Clara Redder, M. C. Smith, and E. Caldwell. Q
Ascorbic acid and carotene or vitamin A content of canned f "
Jour. Nutrition 28:107-116. *
Rosenberg, H. R. 1942. Chemistry and Physiology of the vi . 
Page 96, Inter-Science Publications, Inc. New York, N. Y. '
Sexton, L. L., 1. w. Mehl, and H. J. Deuel, 1946. The relative‘?
vitamin activity of carotene when introduced orally and paren -
in the rat. Jour. Nutrition 31:299-319. . l:
Sherman, H. C. 1944. Principles of Nutrition and Nutritive val i
food. U. S. Dept. Agr. Misc. Pub. N0. 546. F
Sherman, H. C., H. L. Campbell, M. Udiljak and H. Yarmolinski, 1'
Proc. Natl. Acad. Sci. 31:107. G t
Sherwood, R. M. and G. S. F raps; 1935. The vitamin A requireme
hens for egg production. Texas Agr. Exp. Sta. Bul. 514. t
Sherwood, R. M. and G. S. F raps, 1940. Requirements of chicke;
vitamin A when fed on carotene. Texas Agr. Exp. Sta. Bul. 583. z
Wilder, R. M. 1945. Misinterpretation and misuse of the recomm
dietary allowances. Science 101285-288. v
Whitacre, Jessie, 1942. An experience with low-cost diets. Joura
Dietetic Assoc. 18:285-288. '-