The FDA granted this health

In , the New England Journal of Medicine Vol. , No. published a report from the University of Kentucky entitled, MetaAnalysis of the Effects of Soy Protein Intake on Serum Lipids. It was financed by the PTI division of DuPont,The Solae Co. St. Louis, Missouri, a soy producer and marketer. This metaanalysis concluded that soy protein is correlated with significant decreases in serum cholesterol, Low Density Lipoprotein LDL bad cholesterol and triglyceride concentrations. However, High Density Lipoprotein HDLgood cholesterol did not increase by a significant amount. Soy phytoestrogens isoflavones genistein and daidzein adsorbed onto the soy protein were suggested as the agent reducing serum cholesterol levels. On the basis of this research PTI, in , filed a petition with FDA for a health claim that soy protein may reduce cholesterol and the risk of heart disease. It should be noted that only subjects with serum cholesterol of mgdl and higher showed any improvement in the study.The FDA granted this health claim for soy grams of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. One serving, cup or mL of soy milk, for instance, contains or grams of soy protein. Solae resubmitted their original petition, asking for a more vague health claim, after their original was challenged and highly criticized. Solae also submitted a petition for a health claim that soy can help prevent cancer. They quickly withdrew the petition for lack of evidence and after more than , letters of protest were received. In February , Weston A. Price Foundation submitted a petition for removal of this health claim.In January, an American Heart Association review in the journal Circulation of a decade long study of soy protein benefits casts doubt on the FDA allowed Heart Healthy claim for soy protein. This review of the literature compared soy protein and its component isoflavones with casein isolated milk protein, wheat protein, and mixed animal proteins. The review panel also found that soy isoflavones have not been shown to reduce post menopause hot flashes in women and the efficacy and safety of isoflavones to help prevent cancers of the breast, uterus or prostate is in question. Thus, soy isoflavone supplements in food or pills is not recommended. Among the conclusions the authors state, In contrast, soy products such as tofu, soy butter, soy nuts, or some soy burgers should be beneficial to cardiovascular and overall health because of their high content of polyunsaturated fats, fiber, vitamins, and minerals and low content of saturated fat. Using these and other soy foods to replace foods high in animal protein that contain saturated fat and cholesterol may confer benefits to cardiovascular health. The original paper is in the journal Circulation January , .

edit Health risksedit Phytoestrogen Main article PhytoestrogensSoybeans contain isoflavones called genistein and daidzein, which are one source of phytoestrogens in the human diet. Because most naturally occurring estrogenic substances show weak activity, normal consumption of foods that contain these phytoestrogens should not provide sufficient amounts to elicit a physiological response in humans.citation neededPlant lignans associated with high fiber foods such as cereal brans and beans are the principal precursor to mammalian lignans which have an ability to bind to human estrogen sites. Soybeans are a significant source of mammalian lignan precursor secoisolariciresinol containing – µg g dry weight. Another phytoestrogen in the human diet with estrogen activity is coumestans, which are found in beans, splitpeas, with the best sources being alfalfa, clover, and soybean sprouts. Coumestrol, an isoflavone coumarin derivative is the only coumestan in foods.Soybeans and processed soy foods do not contain the highest total phytoestrogen content of foods. A study in which data were presented on an asis wet basis per g and per serving found that food groups from highest to lowest levels of total phytoestrogens per g are nuts and oilseeds, soy products, cereals and breads, legumes, meat products, various processed foods that may contain soy, vegetables, and fruits.edit WomenA literature review suggested that women with current or past breast cancer should be aware of the risks of potential tumor growth when taking soy products, based on the effect of phytoestrogens on breast cancer cell growth in animals.A commentary reviewed the relationship with soy and breast cancer. They stated that soy may prevent breast cancer, but cautioned that the impact of isoflavones on breast tissue needs to be evaluated at the cellular level in women at high risk for breast cancer.edit MenBecause of the phytoestrogen content, some studies, but not all, have suggested that there is an inverse correlation between soybean ingestion and testosterone in men. For this reason, they may protect against the development of prostate cancer. A theoretical decrease in the risk of prostate cancer should, however, be weighed against the possible sideeffects of decreased testosterone, which are still unclear. The popular fear that soybeans might cause reduced libido and even feminine characteristics in men has not been indicated by any study the popularity of the notion seems to be based on the simplistic misapprehension that estrogen and testosterone have a simple, inverse relationship in sexual hormone systems and genderbased behavior. Their interplay is very complicated and largely still unknown.