Too Much Soy?
It's not that long ago that soybeans were considered by most Americans to be "hippie food." But then medical research began accumulating, affirming that soy consumption reduced heart disease and cancer risk, that it lengthened lives and enhanced their quality, and that it provided an almost ideal protein to substitute for animal proteins that almost inevitably come packaged with cholesterol and saturated fat.Cookbook author and chef, Bryanna Clark Grogan weighs in:
Some people are allergic to soy, but then, some people are allergic to wheat, corn, peanuts and many other foods-- that does not mean that they are bad for the rest of us! There is some serious "soy-bashing" going on out there and some of the claims are downright ridiculous! Do your research and make an informed decision!
Soyfoods are, in fact, one of the MOST studied foods in history--studies on soy and humans go back to the turn of the 20th century. Soy is not a "miracle" food, but it is a source of inexpensive and high-quality protein, with proven anti-carcinogenic, antioxidant and cholesterol-lowering properties.
What does Dr. Fuhrman have to say about it? Dr. Fuhrman agrees that incorporating soy and soy products into one's diet will provide a wealth of disease preventing nutrients. But as this exerpt from Eat to Live explains, a diet should not be centered on soy, or any one food for that matter:
Soy products such as soy burgers, soymilk, and soy cheese are much more popular and available today. Recently, the FDA approved soy-containing products as heart-healthy and allowed health claims for soy protein.
Studies have shown soy's beneficial effects on cholesterol and other cardiovascular risk factors. However, there is no reason not to expect the same results from beans of any type--it's merely that more studies have been done on soy than on any other beans. There are numerous studies indicating that soybeans are rich in various anti-cancer compounds such as isoflavones. Most beans are rich in these beneficial anti-cancer compounds, and many different flavonoids with anti-cancer effects are found in beans of various color. I always recommended the consumption of a broad variety of phytochemical-rich foods to maximize one's health. Beans are no exception--try to eat different types of beans, not just soy.
You should be aware that soy nuts, soymilk, and other processed soy products do not retain many of the beneficial compounds and omega-3 fats that are in the natural bean. The more the food is processed, the more the beneficial compounds are destroyed. Remember, though, tofu and frozen or canned soybeans are a good source of omega-3 fat and calcium.
Recently, a few studies appeared showing potentially negative effects of consuming too much soy. One particularly troublesome study done in Hawaii suggested that men with higher tofu intake had more cognitive decline and brain atrophy with aging than men who ate little tofu.1 This data contradicts evidence that Japanese men, who consume tofu regularly, have better cognitive function and lower rates of Alzheimer's disease than American men.2 Obviously, more studies are needed to clarify these suggestive findings and to determine if there is something in tofu or related to tofu consumption that may be harmful. After reviewing these findings, Dr. Harris had soy products from Hawaii tested for aluminum levels and found a significantly higher level of aluminum in tofu from Hawaii than in tofu from the mainland. The aluminum factor may be a plausible explanation for the alleged "brain aging" properties of soy.
In any case, the evidence is not sufficient to warrant being fearful of consuming soybeans as part of a healthful diet. However, this brings to mind my basic theme of nutritional biodiversity--eat a variety of plant foods, and do not eat a soy-based diet.
Most of the processed soy products can be tasty additions to a plant-based diet, but they are generally high in salt and are not nutrient-dense foods, so use them sparingly. In conclusion, the soybean is a superior food, containing the difficult-to-find omega-3 fats. Beans in general are superior foods that fight against cancer and heart disease, which is why you will benefit from using a variety of beans in your diet.
1. White, L. R., H. Petrovitch, G. W. Ross, et al. 2000. Brain aging and midlife tofu consumption. J Am. Coll. Nutr. 19 (2): 242-55.
2. Graves, A. B., I. Rajaram, J. D. Bowen, et al. 1999. Cognitive decline in Japanese culture in cohort of older Japanese Americans in King County, WA: the Kame Project. J. Gerontol. B. Physchol. Sci. Soc. Sci. 54 (3): S154-61.