The Problem of Protein Supplementation

This discussion is concerned chiefly with protein or amino acid evaluation, because this is the big problem of a lacto-ovo vege­tarian diet, and even more so of a strictly vege­tarian diet. We must remember though that in ^-valuating foods for their nutritional value, the appraisal must be based not only on the content of a single food factor but rather on the multiple nutrients present in the particular food.

The building blocks in protein nutrition are called amino acids. Menu planning is concerned with the nutritive values of diets, not of indi­vidual foods. In the vegetarian diet the protein need can be met most efficiently if more than one protein food source is used at each meal. Supplementation is then possible. Like the carpenter who can replace an old window with a new one without completely tearing down the building, the body merely removes the old, worn-out amino acid from the protein under­going repair, and inserts the new one without destroying the original structure of the protein.

In supplemental relationships the strength of the mixture results from the union of two or more protein foods. Both foods must be fed at the same time, and sufficient amounts must be offered if this complementary relationship is to exist. Meals providing from two to three pro­tein-containing dishes, varied from meal to meal, supply the assortment of building stones that can be fitted together to make the needed pattern. Supplementation then means that two foods not having the same limiting amino acid, when used together provide an assortment of amino acids more efficient than either one of the foods used in the mixture.

The protein of wheat is not a complete pro­tein, for example. It is deficient in at least one of the essential building blocks (lysine); and with­out this amino acid, this cereal cannot do a complete job of body building. But milk is rich in lysine. Thus when milk is used with bread or cereal, it makes the protein of the grain more fully useful. This illustrates the supplementary relationships that may exist. This is the reason why bread and cereal have greater nutritive value when combined with milk, or a food con­taining the same properties as milk.

Soybean-flour proteins are valuable in mak­ing up the amino acid deficiencies of wheat and corn. Lysine is inadequate in wheat pro­teins, but abundant in the soybean. Peanut pro­teins are a valuable supplement for the amino acid deficiencies of corn or wheat proteins. In all cases wheat entire is superior to patent white flour. In the comparative studies of the chemistry of proteins from different parts of the grain, bran proteins and wheat-germ pro­teins are found conspicuously rich in the essen­tial almino acids.

It is now known that the supplementation value of vegetable proteins is great. Small amounts of protein of plant origin may greatly increase the biologic value of vegetable proteins of low value. That is, if there is a deficiency of certain amino acids in the menu, the addition of only relatively small amounts of such proteins as soya flour, corn germ, dried brewers' yeast, or sunflower-seed meal may make a complete and efficiently mixed protein-contributing menu. Some foods are more efficient than others in the sense that smaller amounts of them may be used to achieve the same results in building purposes.

It takes fewer grams of protein from eggs, milk, and cottage cheese to make up the needed amino acids than it does. of most legumes, the usual assortment of nuts, and commonly used cereals. The latter are less concentrated in pro­tein, and this also holds true of most vegetables. In the problem of protein supplementation. if small amounts of concentrated sources from either the plant, or advised animal source (milk, eggs, unripened cheese, dried whey powder), are used with larger amounts of less concen­trated sources, the mixed diet will usually fur­nish the needed variety of essential building blocks. Studies show that diets high in protein of poor quality may be more harmful than diets low in protein, but having the essential amino acids in good proportion.

Flours prepared from soybeans, peanuts, sun­flower seed, cotton seed and other seed meals contain proteins of high nutritive value, and may partially replace proteins of animal origin.

It is essential, in order to cook and prepare adequate, appetizing meals, to have the mate­rials handy or available. Protein foods for a lacto-ovo-vegetarian pantry may include :

1. An assortment of various nuts and nut butters, as almond butter, Brazil nuts, and nut flours defatted, as partially defatted almond flour.
2. Cereals of the whole-grain type, as unbolted yel­low cornmeal, oats, unpearled barley, whole wheat, whole rye, millet, brown or natural rice; or corn germ, rice polishings, wheat germ, scalp of sizings, edible bran, and whole-grain flours. Macaroni is not included in whole-grain pastes.
3. Nonfat milk solids (dried skim milk) or dried whey powder (lactalbumin).
4. Legume flours, as lima bean flour, to use in bread, soups, and main dishes ; nut flours, as almond, partially defatted ; ground nut (peanut) granules or flour.
5. Dried brewers' yeast.
6. Legumes, dried or canned lentils, garbanzas, chick-peas, cowpeas, Lima beans, kidney beans, black-eyed peas, common beans, butter beans, pea beans, peas, and soybean products.
7. Seed meals and flours as soybean flour, meal, or grits; or fresh immature green soybeans, mature yel­low soybeans, or fresh bean sprouts.
8. Bread and breadstuffs made of assorted whole grains, as wheat with six-per-cent soybean flour.
9. Low-fat unripe cheese, Dutch or hoop cheese. so. Low-fat, nonconcentrated, commercially pre­pared nut-gluten-soya preparations.