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This chapter deals with the following points: How much protein does a healthy person need? Are there any dangers in eating a high-protein diet? How much protein is assimilated from a meat diet, as opposed to a vegetarian one? Which is the best source of protein?

IMPORTANCE OF PROTEIN—Protein was first identified as a food nutrient in 1838. Protein is needed for muscle function, hormone synthesis, and the production of enzymes. Aside from water, a great proportion of what is in your body is either protein or bone. Growth and repair both require an adequate protein intake.

Protein is built up from amino acids. Of the 20 amino acids in your body, eight are "essential"; that is, they cannot be made within your body. You must get them from the food you eat. The other 12 can be made from those eight.

The issue is not the importance of protein in our diet; all are agreed on that. The question is which is the better protein in our diet: vegetables or meat? Here are some facts:

BETTER ON LOW-PROTEIN DIET—Earlier in the 20th century, Dr. Russell Chittenden, of Yale University, was a leading athletic trainer. He was one of the first to challenge the nutritional theory, that animal-based foods provided the best strength and energy. Chittenden conducted at least three studies that examined the question of whether meat and high protein were really necessary for optimal performance. One involved a study of well-trained athletes.

At the beginning of the study, all were on a typical meat diet. Chittenden had them switch to a plant-based diet for five months. At the end of the study period when their fitness levels were reanalyzed, the athletes had improved a striking 35%! As Campbell, another researcher, later commented, "only the dietary change could have accounted for these remarkable results."

A recent discussion of Chittenden’s research can be found in T.C. Campbell, Muscling out the meat myth, New Century Nutrition, July 1996. Dr. Campbell, Professor of Nutritional Biochemistry at Cornell University, is the director of the massive Cornell-Oxford-China Diet and Health Project.

In their classic study in the 1960s, Mervin Hardinge and his team at Loma Linda University analyzed the complete diets of three groups: meat-eating Americans, lacto-ovo vegetarians (who also eat dairy products and eggs), and vegans. The research team found that the vegans obtained the best mix of essential amino acids, the vegetarians came in second best, and the meat eaters a poor third (M.G. Hardinge, H. Crooks, F.J. Stare, "Nutritional Studies of Vegetarians," Journal of the American Dietetic Association, January 1966).

HIGH-PROTEIN DIET ELIMINATES CALCIUM—An important point concerns the fact that humans do not need a high-protein diet, and it is actually not good for them!

A high-protein diet robs the body of calcium. Healthy young adult men were given carefully controlled diets for nearly four months. During this entire time, they were consuming 1,400 mg. of calcium daily. Their protein intake was also carefully regulated. Test studies revealed that those who ate 48 g. [grams] of protein per day gained 20 mg. [milligrams] of calcium each day. Those who ate 95 g. lost 30 mg. of calcium. Those who ate 142 g. lost 70 mg. of calcium (H. Linkswiler, M.B. Zemel, et al., "Protein-induced hypercalciuria," Federal Proceedings, July 1981).

The researchers concluded their study with this statement: "The calcium loss of 84 mg. daily, which occurred when the high-protein diet was fed, was substantial and, if continued over a period of time, would result in considerable loss of body calcium." The average American intake of protein is 105 g. per day (USDA, Home Economic Research Report, No. 52, September 1994).

Where did that calcium, lost to the body by eating too much protein, come from? It came from their bone reserves. This is an obvious conclusion, since 99% of the calcium in our bodies is in our bones. The high-protein intake group was losing calcium every day, simply because of their high protein consumption. The excessive protein was leaching calcium from bones, even though they were getting plenty of calcium in their diet (1,400 mg. of calcium daily, when the RDA recommended daily allowance is 1000 mg. for women). In contrast, those on the lower-protein diet helped maintain thicker and stronger bones.

HIGH-PROTEIN DIET LEADS TO OSTEOPOROSIS—Two University of Wisconsin researchers, Richard Mazess and Warren Mather, found that Eskimos over the age of 40 have 10%-15% more bone loss than white Americans in the same age range (R.B. Mazess and W. Mather, "Bone mineral content of North Alaskan Eskimos," American Journal of Clinical Nutrition, September 1974). Checking on their diet, they found the Eskimos eat more meat than even average Americans. They also found the Eskimos, with their fish, walrus and whale diet, get a very large amount of calcium from that meat (2,500 mg. daily), yet they lose more calcium than they take in. "The most obvious factor in the . . higher rate of bone loss in middle-aged Eskimos would be their meat diet" (ibid.).

These and other studies clearly show that bone loss and osteoporosis is NOT related to a lack of calcium in the diet. The bigger problem is eating too much protein. If you are eating too much of it, you can eat all the high-calcium foods you want (such as vegetables and milk), yet your bone density will continue to decrease to dangerous levels. Western nations, which consume the most meat, have the highest rate of hip fractures (B.J. Abelow, T.R. Holford, K.L. Insogna, "Cross-cultural association between dietary animal protein and hip fracture," Calciferous Tissue, January 1992).

MEAT ACIDS CAUSE THE BONE LOSS—Research points to the large quantities of acids in meat as the cause of the calcium loss (W.J. Craig, "The Calcium Craze," Nutrition for the Nineties, 1992, pp. 131-146). As the blood becomes more acid, the blood takes calcium from the bones to neutralize the acidity. Increased calcium in the urine then provides a telltale sign of this bone loss (R.B. Mazess and W. Mather, "Bone mineral content of North Alaskan Eskimos," American Journal of Clinical Nutrition, September 1974).

As noted earlier, it is the major meat-eating nations of the Western world which have the most hip fractures (B.J. Abelow, ibid.). An extensive study by four major research centers, working together, analyzed the risk of hip fracture in nearly 10,000 white women over 65. They found that a low-calcium intake—even below 400 mg. per day—did not cause hip fractures (S.R. Cummings, M.C. Nevitt, et al., "Risk factors for hip fracture in white women," New England Journal of Medicine, March 1995).

Interestingly enough, higher consumption of vegetable protein does not appear to be related to osteoporosis or bone fractures (D. Feskanich, W.C. Willert, et al., "Protein consumption and bone fractures in women," American Journal of Epidemiology, March 1996).

Although calcium intake and hip fractures are unrelated in many studies, some studies have shown that an increase in calcium intake can prevent osteoporosis, particularly when the calcium consumption is adequate and the protein intake is relatively low before the age of 30 (R.R. Recker, K.M. Davies, et al., "Bone gain in young adult women," Journal of the American Medical Association, November 1992).

For your information, soy beans and greens are a good natural source of calcium. Some green leafy vegetables (such as collards and lambs-quarters) have even more calcium per serving than soybeans. All the calcium a person needs can be obtained from the vegetable kingdom.

In addition, more calcium is assimilated from vegetables than from dairy products or meat, because vegetables contain less phosphorus. The excess phosphorus in a meal tends to lock with calcium, in that meal, and carry it out of the body.