Soy foods have proponents and opponents, supporters and detractors. Much controversy about soy, maybe even more than whether coffee/eggs/meat are good for you or not! Let’s examine some of the chatter.
Soy grows as beans in pods, like peas. Perhaps you’ve seen these beans and pods and know them as edamame. It is a species of legume yet is not classified as a pulse but as an oilseed plant, as it is grown more for its oil than for using the beans as food. Soybeans are a good source of fiber, protein, iron, omega-3 fatty acids, copper, manganese, and phosphorus, among other nutrients. Concerns include the amount of phytates and phytoestrogens, and that over 90% of US soybeans are said to be genetically engineered and heavily sprayed with pesticides.
First, I am not an opponent of soy, but I am an opponent of the extracts taken from soy, often using hexane and other chemicals, and used in many prepared foods and protein powders. Much of the disagreement over soy’s safety as a food stems from the beans being broken down into components, removed from the whole, and added to many foods. This may lead to consuming too much of one component of soy without its other components for balance. Not good for any food. I favor foods made from the whole bean, like tofu, miso, tempeh, and edamame.
Claims for the health benefits and the health detriments are often made by people who do not really understand the results of the studies and research or are simply regurgitating information they read. One needs to pay special attention to the date of an article, its source, how well the author seems to grasp the science, and was the study on animals or humans. Is the article from 1999 or 2015? A lot is learned over the years, and what was thought to be true in 1999 may have been corrected since. Is the source of the article a well-known soy opponent, like the Weston A. Price Foundation, or is it from a soy food manufacturer? Certainly these two may have different interpretations of the same studies. Is the author a scientist or a school psychologist with knowledge of personal finance (from an actual bio on one article)? How well does the latter understand the terms and measurements and conclusions being referenced? Finally, although many studies are performed on animals, human beings do not always metabolize nutrients the same as rats or guinea pigs and the studies often include amounts that are not feasible for a human diet. Both sides can be pretty convincing, and research for this post had my head spinning a bit!
One of the biggest concerns about eating soy foods is that of the isoflavones, which are sources of phytoestrogens in our diet. It was believed these phytoestrogens could cause cancerous tumors, especially breast cancer, to grow, the way estrogen in hormone replacement therapy did. The other concerns about the phytoestrogens in soy were around men’s and boys’ sexuality – that the effects would make boys grow breasts and men lose virility or fertility. However, phytoestrogens are not the same as the human estrogen hormone and do not have the same effects on our bodies. The association between soy and cancer growth is not supported by all of the research; in fact, there are indications that soy helps prevent certain cancers and most women who have had cancer are no longer told to avoid soy. And further studies on men’s health found that normal consumption of soy did not affect testosterone or estrogen (yes, men have some estrogen, just like women have some testosterone) levels, nor sperm and semen levels.
Phytates are another concern among those who avoid soy. Phytate is the salt form of phytic acid and occurs in edible seeds like nuts, grains, and legumes; also in some roots and tubers. People have read that phytates bind to certain minerals (iron, zinc, calcium, magnesium) and make those minerals unavailable to our bodies. However, this binding only occurs during the meal where the phytates are also being consumed and is not an ongoing stripping of minerals. Only people whose primary foods are grains and legumes need be concerned about possible mineral deficiency. As well, certain ways of preparing the food, like soaking or fermenting, reduce the phytate levels significantly. Therefore, unless one is eating only soy and other phytic acid foods for every meal and never soaking or fermenting those foods, the concern over phytates is way overblown.
A lot of health benefits have been attributed to soy foods also: reduced cardiovascular problems, weight loss, diabetes control, reduction of menopausal symptoms, and cancer prevention. Not all of these claims are borne out by actual studies, and of course results will vary from person to person. It is hard too to definitely state that soy is the savior or the blame, as we are individuals with many variables that affect outcomes.
All in all, I do not feel one should avoid all soy, all the time. Soy foods can be a part of a healthy diet. Strive for organic, whole soy foods as one part of a varied diet. Avoid non-organic soy due to concerns about genetic modification and pesticides. Also avoid isolated soybean derivatives found in highly processed foods and protein powders. In the USA we are able to vary our food choices to get a good mix, and soy can be a good part of that.
Image courtesy of SOMMAI at FreeDigitalPhotos.net