ability of different oils. In 1933 coconut oil made up 75 percent of the fat used, while last year it contributed 8.5 percent of the material used. About 10 times as much cottonseed oil is used today as 10 years ago, and soybean oil now contributes about one-third of the total oil used.

We should therefore give more detailed consideration to the possible differences in the nutritional value of butter and oleomargarine as they are produced today. Butter is "understood to mean the food product usually known as butter, and which is made exclusively from milk or cream or both, with or without common salt, and with or without additional coloring, and containing not less than 80 percent by weight of milk fat, all tolerances having been allowed for. Oleomargarine is defined as a food made from either animal or vegetable fats or a combination of animal and vegetable fats. These fats are mixed with either cream, milk, skim milk, or dried skim milk and water, or with some combinations of these. The finished product must contain not less than 80 percent fat. In addition to these required ingredients the new standards adopted by the Food and Drug Administration, September 6, 1941, permit the use of seven opitional materials: (1) Artificial color, (2) sodium benzoate or benzoic acid, (3) vitamin A with or without vitamin D, (4) diacetyl, (5) lecithin, (6) butter (no butter has been used in oleomargarine manufacture since 1935), (7) salt. The composition of a number of oleomargarines given in Accepted Foods, pages 42-43, shows that most of them contain from 80 to 82 percent of fat.

In the light of modern nutritional knowledge, foods, such as butter and oleo margarine may be of significance in the diet for the following reasons:

1. Concentrated form of energy.

2. Source of essential fatty acids.

3. Carrier of fat soluble vitamins.

4. Effect on requirement of other nutrients.

5. Source of possible unidentified factors.

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1. In order for these food products to exert any or all of these effects, the fat must be properly digested. There is no significant difference in the digestibility of butter and oleomargarine. Langworthy has shown that most of the common fats are utilized to an extent of at least 93 to 98 percent by the human body and can be tolerated in sufficient quantity to furnish 1,000 calories, or more than one-third of the average daily energy consumption. Steenbock, Irwin, and Weber, and Deuel and his coworkers have studied the rate of fat absorption in rats. Steenbock, Irwin and Weber3 found butter oil, halibut-liver oil, and codliver oil to be absorbed at a more rapid rate than lard, corn oil, or partially hydrogenated fats, with butter falling between the two groups. They did not determine whether the rapidity of absorption was physiologically advantageous. Deuel and his coworkers found no consistent difference in the rate of absorption of hydrogenated cottonseed oil, butterfat, or coconut oil.

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A gram of these fats yields 9.1 to 9.3 calories of heat or energy. While carbohyrates and part of the ingested proteins can also serve as a source of energy, the replacement of fat in the diet is limited. Starling stated that "The question of bulk is probably one of the most important factors in determining the need for fat. The human alimentary canal has been developed so as to cope with a diet in which 20 to 25 percent of the energy is presented in the form of fat." Further discussion of this question is made by Anderson and Williams." Drummond recently reported to the Food and Nutrition Board of the National Research Council that the decreased fat intake in England was a serious question previous to the Lend-Lease Act. Thus the presence of appreciable amounts of fat (one-fourth to one-third of the total calories) in the American diet is an important factor.

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Carlson points out that the factor of palatability is of no small importance in insuring an intake of necessary types and amounts of food. Depending on previous habits, the use of butter or oleomargarine may have an important effect on the consumption of other foods.

2 Langworthy, C. A. The Digestibility of Fats, J. Indust. & Engin. Chem. 15: 276, 1923. 3 Steenbock, Harry; Irwin, M. H., and Weber, J.: The Comparative Rate of Absorption of Different Fats. J. Nutrition 12: 103 (July) 1936.

Deuel. H. J., Jr.; Hallman, Lois, and Leonard, A.: The Comparative Rate of Absorption of Some Natural Fats, J. Nutrition 20: 215 (September) 1940.

5 Starling, E. H: The Significance of Fats in the Diet. Brit. M. J. 2: 105 (Aug. 3) 1918. Anderson, W. E., and Williams, II. H.: The Role of Fat in the Diet, Physiol. Rev. 17: 335 (July) 1937.

Carlson, A. J.: Facts and Fancies About Food Fats, Am. J. Pub. Health 31: 1181 (November) 1941.

2. It is well known that natural fats differ in the amount of unsaturated fatty acids present and that certain of the fatty acids appear to be essential in the nutrition of animals (Burr ). Careful exclusion of fat from the diet of rats leads to development of scaly skin, pronounced retardation of growth, kidney lesions, hematuria and early death. There are three unsaturated fatty acids, namely linoleic, linolenic, and arachidonic acids, which are effective in preventing these symptoms, although the individual acids differ somewhat in their specific effects. Natural fats which are most effective in curing this disease are corn oil, linseed oil, olive oil, and lard. Butter and coconut oil even at fairly high levels were not nearly as active in curing the condition. According to Eckstein," butter may vary from 0.2 to 0.5 percent of linoleic acid. Hiditch and Sleightholme 10 report the linoleic acid content of butter to be from 1.9 to 3.7 percent. The linoleic acid content of oleomargarine will vary, of course, depending on the fats used by its manufacture, but it may be quite high if cottonseed oil is used in considerable amounts. The untreated cottonseed oil may contain 35 to 50 percent of linoleic acid; however, the oil is usually hydrogenated, but even a hydrogenated cottonseed oil may contain 13 percent of linoleic acid according to chemical assays (Hoagland and Snider "). On the basis of rat assays, Burr has found approximately 2 to 5 percent of linoleic acid in oleomargarine and 1 to 4 percent of butter.

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Even though butterfat is lower than the oleomargarines in the essential unsaturated acids, there is apparently sufficient present to meet the demands when whole mineralized milk is used as the sole article of diet. Rats have been maintained for long periods of time in excellent health on such a diet, and Anderson, Elvehjem, and Gonce have maintained dogs on such a diet for 3 years with the comment that the animals had very excellent fur coats. Infants, of course,. have been maintained on milk diets for long periods of time. There may be a small amount of linoleic acid in the phospholipids of the skim milk, and the high lactos intake may have some sparing effect when whole milk diets are used. Some difficulty in rats has been reported when 9 percent of butter fat has been used in sythetic diets as the sole source of fat, but this difficulty may be due in part to the development of rancidity in these purified rations; which would. cause rapid destruction of the unsaturated fatty acids.

Some question has been raised about the impo. tance of unsaturated fatty acids in human nutrition, and it must be admitted that very little work has been done. on human beings. Brown and his coworkers 1 kept two infants on a diet extremely low in fat and observed no symptoms except repeated mild attacks of impetigo. They did find a moderate decrease in the degree of unsaturation of the serum fatty acids. Hansen 15 has reported a similar decrease in infants suffering from severe eczema. Brown and his coworkers maintained an adult for a period of 6 months on a low fat diet which produced the typical fat deficiency syndrome in rats without demonstrable harm in the man. Linoleic and arachidonic acid contents of the blood serum did show a decrease. The highly unsaturated fatty acids should be provided in the diet of human beings, but it appears that for individuals on average diets no difficulty in this respect will be observed by shifting from butter to oleomargarine or vice versa.

3. Many fats are important carriers of the fat soluble vitamins; in fact, the original discovery of vitamin A was dependent on the use of fat-poor experimental diets. Butterfat was used in many of these early studies, and it was soon recognized that vegetable fats and many animal tissue fats were devoid of vitamin A. While butterfat has served as an important source of vitamin A in temperate zones, fish oils have played a similar role in Arctic regions.

Burr, G. O. On the Necessity of Fats in the Diet, Chemistry and Medicine, edited byM. B. Visscher, Minneapolis, University of Minnesota Press, 1940, p. 101.

Eckstein, H. C.: The Linoleic and Linolenic Acid Contents of Butter Fat, J. Biol. Chem, 103:135 (November) 1933.

10 Hilditch, T. P., and Sleightholme, J. J. Variations in the Component Fatty Acids of Butter Due to Changes in Seasonal and Feeding Conditions, Biochem. J. 24: 1098, 1930. 11 Hoagland, R., and Snider, G. G.: Nutritive Properties of Steam Rendered Lard and 12 Burr Personal communication.

Hydrogenated Cottonseed Oil, J. Nutrition 22: 65 (July) 1941.

13 Anderson, H. D.; Elvehjem, C. A., and Gonce, J. E., Jr.: A. Comparison of the Nutritive Values of Raw, Pasteurized, and Evaporated Milks for the Dog, J. Nutrition 20: 433 (November) 1940.

14 Brown, W. R.; Hansen, A. E.; Burr, G. O.; and McQuarrie, I.: Effect of Prolonged Useof Extremely Low Fat Diet on an Adult Human Subject, J. Nutrition 16: 511 (December) 1938.

15 Hansen, A. E.: Serum Lipids in Eczema and in Other Pathologic Conditions, Am. J. Dis.. Child. 53 933 (April) 1937.

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Most workers agree that many unfortified oleomargarines contain insignificant amounts of vitamin A. Some of the oleomargarines made from beef oleo oil may carry fair amounts of vitamin A. A significant portion of the oleomargarine is now fortified to an extent of 9,000 international units per pound. All the oleomargarine sold as a table fat should be fortified. The vitamin A content of butter is known to vary depending on the feed of the cow, but most of the butter produced in the Dairy Belt of the United States will contain 5,000 to 20,000 international units per pound. According to the values given by Dornbush, Peterson, and Olson the minimum value for winter-produced butterfat is 3 micrograms of carotene and 7 micrograms of vitamin A per gram. The maximum value for summer-produced butterfat is 10 micrograms of carotene and 13 micrograms of vitamin A per gram. Assuming that 1 pound of butter contains 38 grams of butterfat and that 1 international unit equals 0.6 microgram of carotene and 0.3 microgram of vitamin A, the foregoing values give 10,584 to 22,200 international units per pound. In isolated areas where the feeding practices are very poor, values below 10,000 international units per pound may be obtained. There may be some loss of vitamin A in butter during storage, but fortified oleomargarine is also subject to this loss.

If we use the average per capita consumption of butter (17 pounds) and the average vitamin A potency as 12,000 international units per pound, butter can supply between 6,000 and 7,000 international units daily to each person in the United States. Many persons eat twice the average amount of butter and would, therefore, obtain one-fourth of their total daily requirement from butter. It is obvious that only fortified oleomargarines and butter can be compared when the vitamin A is considered.

Butter contains from 50 to 500 international units of vitamin D per pound (Wilkinson 1). Thus it is not a rich source, but a generous intake of butter may supply one-sixth of the total requirement. Oleomargarine is practically devoid of vitamin D, although it may carry significant amounts if fish-liver oils are used for the addition of vitamin A. In England both vitamins A and D are added to margarines. The council accepts no special claims for the vitamin D added to oleomargarines in this country.

Butter is low in vitamin E, although there is sufficient in whole milk to allow reproduction in rats and dogs. Since the oils from seeds are rich sources of vitamin E, oleomargarine should carry appreciable amounts of this vitamin if the oleomargarines are properly prepared. No nutritional claims are recognized for vitamin E at the present time.

Although the vitamin K content of butter has not been determined accurately, it is obvious that butter contains relatively little of this vitamin. Oleomargarine also carries relatively little vitamin K, since the seeds of plants contain less vitamin K than do the leafy parts of the plant. Since the requirement for vitamin K may be satisfied by intestinal synthesis, at least in adults, any difference in the amount of this vitamin in butter and oleomargarine is not of any great significance. In summary, then, butter supplies more vitamin A and vitamin D than margarine unless it is fortified, and oleomargarine supplies more vitamin E than butter.

4. Evidence has been accumulating to show that the amount of fat in the diet may affect the body's requirement for other nutrients. In experimental animals the isocaloric replacement of sucrose with fat produces a significant decrease in the vitamin B1 requirement. Natural fats such as butter, lard, or corn oil all produce the same effect.18 In the rat high levels of fat appear to increase the riboflavin requirement, but again all fats function equally.1 When animals are placed on a diet of skim milk fortified with minerals, a large percentage of the ingested galactose of the milk sugar is excreted in the urine.20 When butterfat, lard, corn oil, and coconut oil were added to the diet to the extent of 3 to 4 percent, the loss of galactose in the urine was prevented.

16 Dornbush, A. C.; Peterson, W. H., and Olson, F. R.: The Carotene and Vitamin A Content of Market Milks, J. A. M. A. 114: 1748 (May 4) 1940.

17 Wilkinson, H.: The Vitamin A and Vitamin D Contents of Butter: II. Seasonal Variation, Analyst 64: 17, 1939.

18 Arnold, A., and Elvehjem, C. A.: Am. J. Physiol. 126: 289 (June) 1939.

19 Mannering, G. L.; Lipton, M. A.; and Elvehjem, C. A.: Relation of Dietary Fat to Riboflavin Requirement of Growing Rats, rPoc. Soc. Exper. Biol. & Med. 46:100 (May) 1941.

20 Schantz, E. J.; Elvehjem, C. A.; and Hart, E. B.: The Relation of Fat to the Utilization of Lactose in Milk, J. Biol. Chem. 122: 381 (January) 1938.

The significance of choline in animal nutrition is now definitely established," although its importance in human nutrition is not clear. At first thought one would expect the fats in the diet to supply much of the needed choline; however, purified fats have probably lost much of their phospholipid choline. Cereal products and skim milk, which carry little or no fat, supply much of the choline as well as other substances exerting a choline-like effect, needed in the diet.

In the rat unsaturated fatty acids may have some sparing action on vitamin B.; however, the significance of unsaturated fatty acids in human nutrition has already been discussed. According to present knowledge, then, the ingestion of butter or oleomargarine will not alter the requirement of other nutrients to any significant degree.

5. In studies designed to measure any possible difference in the nutritive value of butter and vegetable oils, Schantz, Elvehjem, and Hart 22 showed that butterfat homogenized into raw skimmed milk with ample fat soluble vitamins and minerals added gave better growth when fed to weanling rats than did corn oil, coconut oil, cottonseed oil, and soybean oil fed in a like manner. The differences are most readily obtained in young growing rats and when the diet contains lactose. The factor responsible for the superior growth follows the saturated fraction of the butterfat.23 The unsaturated fraction of butterfat is relatively rich in a compound which by hydrogenation may be converted to an active compound. Corn oil, coconut oil, cottonseed oil, and soybean oil apparently do not contain this compound, since hydrogenation of these vegetable oils does not improve their nutritive value when incorporated into skim milk." That butterfat should have a different nutritional effect is not surprising, since several additional fatty acids have been isolated from butterfat (Hilditch 25). Similar differences have been obtained by Gullickson and his coworkers 2 using calves as the experimental animal. They also found that the animal fats such as lard and tallow gave results similar to those obtained with butterfat. It is most interesting that some of the calves on a low fat diet made excellent gains and were healthy and thrifty. Thus the level of fat in the diet is very important in estimating the superior values of animal fats over vegetable fats. It is well known that rats grow very well on synthetic diets containing 2 percent of corn oil. Euler and her coworkers" obtained better growth in rats on a purified diet containing oleomargarine than on a similar diet containing butterfat. The percentage of fats in their diet was also lower than that in whole milk, and the rate of growth in all their animals was rather low. It is possible that both rats and calves was able to synthesize additional fatty acids when they are on low fat diets.

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Whether these results enter into the question of the relative value of butter and oleomargarine in human nutrition remains to be determined. Holt and his coworkers have reported that soybean oil is superior to butterfat in infant nutrition, because the oil is more easily absorbed than butterfat. At present it is unknown whether the factors indicated to be essential in the animal experiments are needed by human beings. If they are needed, they are probably more important in growing children than in adults. If they must be supplied in the diet, the other ingredients of the diversified diet consumed by most adults will probably supply sufficient amounts of the factor. Many of the oleomargarines now manufactured contain some animal fats in addition to the vegetable oils. These animal fats should supply the same factors that are present in butterfat.

It is, therefore, possible to conclude that at present there is no scientific evidence to show that the use of fortified oleomargarine in an average adult diet

21 Griffith, W. H.: The Nutritional Importance of Choline, J. Nutrition 22: 239 (Septem. ber) 1941.

22 Schantz, E. J.; Elvehjem, C. A. ; and Hart, E. B.: The Comparative Nutritive Value of the Fatty Acid Fractions of Butter Fat, J. Dairy Sc. 23: 1205 (December) 1940.

23 Schantz, E. J. Boutwell, R. K: Elvehjem, C. A. and Hart, E. B.: The Nutritive Value of the Fatty Acid Fractions of Butter Fat, J. Dairy Sc. 23: 1205 (December) 1940. 24 Boutwell, R. K.; Geyer, R. P.; Elvhjem, C. A.; and Hart, E. B.: The Effect of Hydrogenation on the Nutritive Value of the Fatty Acid Fractions of Butter Fat and of Certain Vegetable Oils, J. Dairy Sc. 24: 1027 (December) 1941.

25 Hilditch, T. P.: The Chemical Constitution of Natural Fats, New York, John Wiley & Sons, Inc., 1940, p. 385.

20 Gullickson, T. W.; Fountaine, F. C.; and Fitch, J. B.: Various Oils and Fats as Substitutes for Butter Fat in the Ration of Young Calves, J. Dairy Sc. 25: 117 (February) 1942.

Euler, Beth V.; Euler, Hans V.; and Sobert, Inez: Effects of Fats and Fat Soluble Substances on Rat Growth: II. Arkw. Kemi. Mineral. Geol. 15B, No. 8, 1941.

28 Holt, L. E., Jr.: Irdwell, H. C.; Kirk, C. M.; Cross, D. M.; and Neal, S.: Studies on Fat Metabolism, J. Pediat. 6: 427, 1935.

would lead to nutritional difficulties. A similar statement is probably justified in the case of growing children, but preliminary results from animal experiments indicate that more work is necessary before any specific conclusions can be made. Since the nutritional factors have not all been identified, and since butter contains numerous additional fatty acids of unknown nutritional significance, the consuming public has a right to demand that the practice of identifying oleomargarine and butter so that anyone can differentiate between them should be continued.

[Document No. 4]

MARGARINE QUOTED FROM THE REPORT OF THE NATIONAL NUTRITION CONFERENCE FOR DEFENSE

That the Government should take the initiative in encouraging industry to bring on the market low-cost, highly nutritious foods in forms acceptable to consumers, such as soybean, peanut, and milk products. No milk nutrients, should be wasted. Skim-milk products, dry and fluid, are vitally needed and should be put on the market at low price.

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Special-interest groups, through private combinations and pressure on public authority, have erected interstate or regional trade barriers which reduce the opportunity for efficient distribution of foods into consumers' hands, such as discriminatory administration of milk ordinances. We recommend elimination of such restraints.

We oppose the following State or Federal legislation: (a) Laws which discriminate against wholesome nutritive foods, such as taxes on colored and uncolored margarine; (b) laws or regulations which favor food products according to the locality in which they are produced, such as laws which permit eggs to be labeled as fresh only if they are produced within a certain area; (c) special taxes to place special kinds of retailers at a disadvantage with others; (d) excise, sales, and processing taxes on foods; (e) price maintenance and unfair sales laws which permit and encourage private price fixing without public control; () State marketing or prorate acts which tend to increase monopoly control and raise prices of foods to consumers.

There are some bottlenecks, both public and private, which now contribute to keeping food prices and margins higher than they otherwise would be. Where monopoly, racketeering, and illegal practices tending to raise food prices are found, whether this be in agriculture, industry, or labor, the Government is urged to continue its vigorous enforcement policies under the antitrust laws. The ability to produce, process, and distribute foods at prices within the reach of low-income families is hampered at present by some forms of municipal, State, and Federal legislation. Examples of such legislation include restrictions not designed solely for the protection of the health of consumers, or the public welfare; certain forms of price-fixing or price-maintenance legislation; internal trade barriers; taxes upon foods and particular methods of distribution. We urge a careful and judicious reexamination of all such laws to determine their effect on all parties con