An editorial in the November, 1959, Lancet, page 957, observed that “formerly vegetable proteins were classified as second-class and regarded as inferior to first class proteins of animal origin; but this distinction has now been generally discarded. Certainly some vegetable protein, if fed as the sole source of protein, are of relatively low value for promoting growth; but many field trials have shown that the proteins provided by suitable mixtures of vegetable origin enable children to grow no less well than children provided with milk and other animal proteins.”
The key thought here is variety. Most plant foods are low in one or more of the essential amino acids, but a sufficiently varied diet will supply all of them in abundance. “In many mixed diet, even if wholly of plant origin, the proteins are sure to be sufficiently varied to compensate for any individual inadequacies in amino acid content,if only the total amount of protein is sufficient.”- Samson Wright’s Applied Physiology, Eleventh Edition. Revised, 1965, p. 418.
Condensed from Unmeat; by Stroy E. Proctor, Jr., M.P.H. and Leilani Proctor. Copyright(c) 1973 by Southern Publishing Association, Nashville, Tennessee