Hope's Edge_ The Next Diet for a Small Planet - Frances Moore Lappe [87]
So now you know how the National Academy of Sciences arrived at the recommended protein allowances that are used throughout this book. Since it is set 30 percent above the average, it is more than most people need. Some protein authorities, however, believe that the allowance still may not be high enough to include 97.5 percent of the population.
Special Needs
While I’ve said that protein complementarity is not necessary for most of us, it does come in handy for those who must increase their protein intake without increasing calories. This is true for those whose bodies are under special stress, especially pregnant and breast-feeding women. A pregnant woman is advised to up her protein intake by an additional 30 grams a day (a 68 percent increase) but her calorie intake by only 300 calories (a 15 percent increase). A breast-feeding woman is advised to add 20 grams of protein to her diet but only 500 more calories; that would be 45 percent more protein but only 25 percent more calories. With these high protein needs, it becomes important to make the most of all the protein you eat, and combining complementary protein can help do that.
Many are concerned about the protein needs of children. Actually, they do not need more protein in relation to their calorie intake than adults. But because infant and young children cannot digest certain plant foods as easily as adults, some special care is needed in meeting their needs on a largely plant food diet. Michael and Nina Shandler have provided guidance for parents in The Complete Guide and Cookbook for Raising Your Child as a Vegetarian (Schocken Books, 1981). It also contains sound nutritional advice for pregnant women.
4.
Protein Complementarity: The Debate
IN THE PREVIOUS chapter I tried to dispel the myth that you need lots of meat to get the protein you need, while confessing that Diet for a Small Planet had helped create a new myth—that to get the protein you need without meat you have to conscientiously combine nonmeat sources to create a protein that is as usable by the body as meat protein. Protein complementarity is not the myth; it works. The myth is that complementing proteins is necessary for most people on a low- or nonmeat diet. With a healthy varied diet, concern about protein complementarity is not necessary for most of us.
Nonetheless, for several reasons, I would like to explain briefly protein complementarity. The first reason is that it is useful for people with a considerably higher than average protein need, including pregnant and breast-feeding women. Second, understanding protein complementarity does disprove any notion that animal protein is uniquely qualified to meet nutritional needs. But perhaps my real reason is simply that it fascinates me, particularly since I realized that complementary protein combinations evolved spontaneously as the basis of virtually all of the world’s great cuisines.
If all proteins were the same, there would never have been a controversy about preferable sources for humans; only quantity would matter. Proteins, however, are not identical. The proteins which our bodies use are made up of 22 amino acids in varying combinations. As already noted, 8 of these amino acids cannot be synthesized by our bodies; they must be obtained from outside sources. These 8 essential amino acids (which I will refer to as “EAAs”) are tryptophan, leucine, isoleucine, lysine, valine, threonine, the sulfur-containing amino acids (methionine and cystine), and the aromatic amino acids. (Histidine is also necessary for children.)
Our bodies need all of the EAAs simultaneously in order to carry out protein synthesis. If one EAA is missing, even temporarily,