Even though soy is a good source of protein, fiber, calcium and a variety of other vitamins and minerals, it still remains a highly controversial food. While many espouse its strengths, others are absolutely convinced that soy is bad for you.
To try to get at the truth, let’s examine some of the soy myths.
Myth #1: Soy Causes Breast Cancer
One of the biggest concerns about soy is that it causes (or increases the risk of) cancer — particularly breast cancer. These health concerns stem from the fact that soy contains a concentration of phytoestrogens, which are a group of natural compounds that bears a mild resemblance to estrogen chemically. It is important to point out that phytoestrogens are not estrogen. In fact, there is a large body of scientific work which convincingly demonstrates that soy decreases-rather than increases—cancer risks and also lowers cancer recurrence rates.
- Early research conducted at University of Southern California suggests that women who have one serving of soymilk or tofu daily are 30 percent less likely to develop breast cancer.
- Another study shows that soy can help breast cancer survivors; women who ate more soy had 29 percent lower mortality rates and 36 percent lower recurrence rates.
- Further research shows that the increased survival rate and decreased risk of cancer recurrence may be due to soy phytoestrogens’ effect on BRCA and other breast cancer genes (turning those tumor suppressor genes back “on”.)
Myth #2: Soy Reduces Testosterone in Men and Leads to Prostate Cancer
Another prevalent misconception is that soy decreases testosterone levels in men and can possibly lead to prostate cancer. Neither assertion is valid.
- A meta-analysis published in Fertility and Sterility which was based on more than 50 treatment groups, showed that soy products do not affect reproductive hormones, including testosterone levels, in men.
- The American Journal of Clinical Nutrition published an analysis of 14 studies which showed that an increased intake of soy actually reduced the risk of prostate cancer by 25% while risk was reduced 30% when ingesting nonfermented soy products like soymilk and tofu.
Myth #3: All Soy is Genetically Modified
Soy can be found in both its GMO and non-GMO forms. Most GMO in the U.S. is fed to livestock while the majority of soy food manufacturers use non-GMO soy; non-GMO tofu, tempeh, and soymilk are widely available and clearly labeled non-GMO. And by law all “organic” products in the U.S. exclude GMOs. If this is a concern for you, just make sure to choose organic soy products to ensure you are buying non-GMO soy.
A Few Rules Of Thumb When Eating Soy
While the dangers of soy have been routinely overstated, it is still important to note a few ‘rules of thumb’ when it comes to soy:
- Like many foods, too much of a good thing is still too much. A good guideline is to keep your soy consumption down to three or five servings daily of whole and minimally-processed soy.
- Stick to whole, unprocessed forms of soy which provide you with good quality, health promoting protein. Whole soy includes edamame and roasted soynuts. Minimally-processed soy includes tofu and soymilk. Fermented soy can be enjoyed as tempeh, natto and miso. For an added bonus, try calcium-set tofu which can be one of the richest sources of calcium in a plant-based diet.
- Avoid or drastically reduce consumption of highly-processed soy, i.e. soy protein concentrates or isolates, and soy ‘junk’ food like soy cheese and some meat substitutes.
Removing soy would eliminate all of its healthful benefits! So consider including this nutrient-rich, high- protein food as part of a delicious, balanced plant-based diet.