Striking at the Soy Heart Health Claim

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February 19 was a big day for the Weston A. Price Foundation. President Sally Fallon and Secretary Geoffrey Morell delivered a 65-page petition to the offi ces of the FDA in Rockville, Maryland, in which the Foundation strongly urged the agency to retract the soy-prevents-heart disease health claim. This is the claim that people read when they visit grocery stores and pick up packages of soy milk, veggie burgers and other soy products that contain more than 6 grams per serving of soy protein. This FDA health claim greatly bolstered soy’s reputation as a “miracle food” and boosted sales from under one billion dollars per year in 1999 to more than four billion dollars just a few years later. In addition to myself and Sally Fallon, our petition was signed by three worldclass scientists: Kilmer S. McCully, MD, father of the homocysteine theory of heart disease, winner of the 1998 Linus Pauling Award and author of The Homocysteine Revolution and The Heart Revolution; Mary G. Enig, PhD, the world renowned biochemist and nutritionist who exposed the dangers of trans fats in the food supply back in the 1970s, vice president of WAPF, author of Know Your Fats and co-author of Eat Fat Lose Fat and Nourishing Traditions; and Galen D. Knight, PhD, a biochemist who has carried out pioneering research on the role of vitalethine in humoral immunity and cancer development.

Standard of Scientific Agreement

Our petition pointed out that according to section 403 (4) (3) (B) (i) of the Federal Food, Drug and Cosmetic Act, FDA can authorize a health claim only if the standard of signifi cant scientific agreement is met. In fact, our review of the scientific literature on soy and heart disease indicated that soy protein does not reliably lower cholesterol, does not lower homocysteine, does not prevent heart disease and may cause, contribute to or accelerate the development of heart disease, particularly heart arrhythmias and cardiomyopathy, an increasingly prevalent condition that afflicts one in 500 Americans and is the leading cause of death in young athletes.

We pointed out that in approving the health claim in 1999, the FDA relied heavily on studies on soy and cholesterol that were deeply flawed because of the routine use of casein as the control. Casein is a fractionated milk protein product that is high in the amino acid methionine and seriously deficient in cysteine. Research at the Faculty of Agriculture, Shizuoka Univeristy, Japan, has shown that compared to other proteins, casein will signifi cantly raise total cholesterol levels and lower HDL levels. Therefore, casein is an extremely poor control in terms of evaluating soy protein’s effect on cholesterol.

The Steep Price of Cholesterol Lowering

The most commonly accepted explanation for soy protein’s cholesterol lowering potential— if and when cholesterol lowering actually occurs—is stimulation of LDL receptor activity. As Dr. Knight established, this mechanism would serve as compensation for a soy-dependent increase in bile acid excretion. Because this loss of bile would be accompanied by losses of fat-soluble thyroid and steroid hormones and of fat-soluble vitamins, cholesterol-lowering by soy protein would be achieved at a steep price.

Dr. Knight furthermore suggested that this cholesterol-lowering mechanism would compromise normal levels of the monooxygenase receptor for vialethine, an endogenous regulator of key metabolic pathways in the body. Vitalethine is critical to the body’s ability to ward off and fi ght cancers through humoral immunity. Vitalethine is made from the amino acid cysteine and pantothenic acid. Although soybeans actually contain good levels of cysteine, there is limited bioavailability because it is bound up in soy’s protease inhibitors.

Homocysteine

Dr. McCully’s homocysteine theory of arteriosclerosis is based on evidence that elevation of blood homocysteine concentrations is a major contributing factor in cardiovascular disease. Homocysteine may become elevated as the result of dietary, genetic, metabolic, hormonal or toxic factors, including dietary or absorptive deficiencies of vitamins B6, B12 and folic acid. Because soybeans are totally devoid of B₁₂ and can increase the body’s requirements for B₁₂, they can raise homocysteine levels.

Longstanding Concerns

The third section of our petition documented longstanding concerns in the scientific community—including warnings from the FDA’s own Laboratory for Toxicological Research, the National Center for Environmental Health Sciences, the Israeli Health Ministry, the French Food Agency and the German Institute for Risk Assessment—about soy’s possible role in carcinogenesis, thyroid disease, reproductive health problems (including infertility) and other health problems.

Hearing Requested

In conclusion we asked the FDA to hold a public hearing on the issues we raised in our petition.

In 2005, the Weston A. Price Foundation protested a soy-prevents-cancer health claim filed by the Solae Company with the FDA. Solae subsequently withdrew their petition in the face of massive evidence that soy can cause, contribute to and accelerate the growth of cancer, particularly breast cancer.

Read our petition here (PDF).

This article appeared in Wise Traditions in Food, Farming and the Healing Arts, the quarterly magazine of the Weston A. Price Foundation, Spring 2008.

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