Articles ¬ Senior's Advocate ¬ SoyIt seems as though soy is everywhere and as with most things that are popular, opinions on it are polarized. In this Natural Advocate, I am going to try to give you the most balanced and factual information that is currently available on soy products.
The soy bean is a member of the legume family. Its products include edible oil, imitation meats, food additives, flour, grits, and stock feed. Due to soy’s wide spread use as a food additive, allergic reactions to soy products are becoming more common. Soy beans have seven of the eight essential amino acids, which means like all legumes, it is not a complete protein. Soy beans are a rich source of calcium, iron, zinc, phosphorus, magnesium, B-vitamins, omega 3 fatty acids and soluble fiber. Soy is not readily digestible without fermenting. Fermentation is also important to decrease the amount of phytic acid contained in soy (which is also available in other grains and beans). This chemical can depress thyroid function and interfere with the uptake of essential minerals. Fermented soy products includes; soy sauce, tofu, tempeh and miso.
Soy also contains a group of plant estrogens (phytoestrogens) called isoflavones. Two of these isoflavones, genestin and daidzen, are the substances believed to have protective effects on our health. Many aspects of health have been associated with eating soy — including cancer prevention and reduced risk of heart disease, osteoporosis, and menopausal symptoms, among others.
The cholesterol lowering effect of soy and its role on heart disease was widely recognized in the mid 1990’s when the results of a meta-analysis of 38 clinical studies were published. The results demonstrated that a diet with significant soy protein reduces total cholesterol, LDL cholesterol (the "Bad" cholesterol), Triglycerides and decreases blood clotting (thrombosis), which reduces the risk of heart attack and stroke.
In addition to being high in calcium, soy also contains magnesium and boron, which are important co-factors of calcium for bone health. The Isoflavones in soy foods may inhibit the breakdown of bones. Daidzein, a type of isoflavone, is actually very similar to ipriflavone, which is used throughout Europe and Asia to treat osteoporosis.
In Japan, where soy foods are commonly consumed daily, women are only one-third as likely to report menopausal symptoms as in the United States or Canada. Current studies have showed that soy by regulating estrogen levels, only sometimes helps alleviate menopausal and PMS symptoms.
What we know at this point is the phytoestrogens in soy foods are "anti-estrogens". In other words, they may block estrogen from reaching the receptors, therefore potentially protecting women from developing breast cancer and men prostate cancer. Studies found that pre-menopausal women may benefit from eating soy foods as their natural estrogen levels are high. However, this may not be true to post-menopausal women. Studies found that soy could become "pro-estrogen" in women with low levels of natural estrogen. Therefore, concentrated soy supplements may add estrogen to the body and increase breast cancer risk in post-menopausal women.
Based on all available information, here is my conclusion. Nutritional studies are often funded by people with special interest and bias. Don't believe anything that you hear or read unless you check that they come from at least three reliable sources. I do not recommend soy supplements or concentrates as I feel that they need to be studied more, but I do not feel that one to two servings of soy daily is harmful and in fact may be beneficial. A serving would include; 1/2 cup cooked soybeans, 1 cup of soy milk, 1/4 cup of dry texturized vegetable protein (tvp), 1/2 oz. isolated soy protein or 1/2 cup tofu.
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