Written by: Rebecca Baird, August 11, 2010
Soy has been viewed by many health professionals and registered dietitians as the ultimate protein source for nutritional health, but new research is showing that this assumption may be far from the truth. According to the American Heart Association, supplementing the diet with soy protein has no significant benefit. According to the American Cancer Society “soy protein could increase cancer risk in ways that are not yet understood. Phytochemicals, naturally occurring plant chemicals (isoflavones) that are present in soy, may affect the way cancer cells grow. ..Soy might act in the same way as estrogens to increase the growth of estrogen-responsive cancers, such as breast or endometrial cancer.”
The results of studies concerning the link between soy consumption and male infertility have been interesting and revealing as well. A study done in 2005 by Dr. Lynn Fraser and her team of UK scientists revealed that isoflavones (genistein) could damage human sperm. At a conference in Copenhagen Dr. Fraser pointed out that, “she had carried out previous research on mouse sperm that suggested similar findings, and that tests on human sperm had proved it was 10 to 100 times more sensitive to (isflavones) genistein. ‘Human sperm are responding to very low concentrations – well within the amounts that have been measured in people’s blood’, she said. The findings might suggest that women who eat soya-based products and legumes should change their diet… prior to conception.” Soy beans contain pytoestrogens which is a natural defense mechanism for the plant. Pytoestrogens when consumed by predators, limit a herbivores reproduction. Thus, the predator’s population decreases and more plants prosper. So it makes sense that human sperm (and the reproductive system) would be adversely affected by the consumption of soy products. A study published in Environmental Health Perspectives states that, “diverse animals such as cattle, mice, and quail have been shown to suffer reproductive failure due to dietary phytoestrogens.”
Some studies show that fermented soy foods are the only foods which will not contribute to health problems but will in fact promote health. In Asia, the traditional fermented soy foods are considered to have more health promoting benefits when consumed in moderate amounts than the super-processed soy products that are consumed in the West. For example, a study (1) of the culturing method involved in the production of the Japanese traditional food miso, came to the conclusion that the culturing process itself led to a “lower number of cancers per animal” and a “lower growth rate of cancer compared to controls.” The researchers also indicated that it was not the presence of any specific nutrient that was cultured along with the soyabean paste but rather the cultured soy medium itself that was responsible for the health benefits associated with miso consumption.