If you read my last post about dairy and calcium (cruelty to cows AND calcium leaching from your bones?!) you’re probably on the hunt for some awesome plant-based milks. Today there are endless non-dairy milk options made from sunflower seeds, flax, hemp, coconut, oats, and even hazelnuts. Despite the variety, soy milk will always have a special place in my heart: it’s the perfect thickness for rich hot chocolate, the base for amazing soy yogurts, and goes perfectly with a vegan chocolate chip cookie. Taste, however, shouldn’t be the most important thing when choosing any food. In my mind, health should come first, and I repeatedly hear concerns from everyone from my mom to my neighbors about the “dangers” of soy. So, of course, I set out on a research journey to find out if the claims were true– soy is rumored to cause cancer, thyroid problems, to “feminize” men, and to cause babies to spontaneously combust (okay I made up that last part, but there are people out there that believe we should make soy formula illegal.)

The first group I encountered when searching the dangers of soy was the Weston A. Price Foundation, an anti-soy group that promotes the consumption of minimally processed animal products and raw dairy. Weston Price was a dentist who, in the 1920s, observed good dental health in pre-industrial populations that he studied around the world. Price attributed this to their minimally processed diet in his 1939 book called Nutritional and Physical Degeneracy. Over 50 years after his death the WAPF was started with the goal of spreading his nutritional findings. Price, however, neglected the short life expectancies, high infant mortality rates and malnutrition endemic to the very populations he extolled for their brilliant teeth. Current doctors and nutritionists including Joel Fuhrman MD, John Robbins, and Stephen Barrett MD have called the nutritional claims of the Price Foundation, which encourages high saturated fat and cholesterol consumption, “contrary to contemporary medical understanding.” As The Guardian observed in a 2010 article, the majority of anti soy articles and studies can be attributed to this one organization.

So why the critique of soy? The WAPF asserts that the phytoestrogens (plant hormones) contained in soy may disrupt sexual development, affect fertility, and increase the risk of breast cancer. The foundation cites animals studies to support the “dangers” of soy consumption, despite the fact that phytoestrogens behave  differently in different species and the injection of high levels soy isolates cannot be compared to moderate consumption of whole soy foods. That same 2010 Guardian article reported that the UK commissioned a 440-page report investigating this and found no evidence that populations with high soy consumption have altered sexual development, fertility issues, or high rates of breast cancer. China is, after all, the most populous nation on the planet and has the lowest global rates of breast cancer despite having the highest soy consumption (dietary studies show that in China the average person consumes 2-3 servings of soy per day, and China is ranked 142nd for breast cancer incidence while the US is rated #1). A 2001 review in the Journal of the American Medical Associated found no significant differences between young adults who as infants, in a 1965-1978 controlled feeding study, had consumed either soy formula or cow’s milk formula (Strom et al., 2001). A 2002 study from the Arkansas Children’s Nutrition Center states that multigenerational animal studies with diets including soy protein isolate containing isoflavones (SPI+) have shown no ill-effects. There is no epidemiological evidence or human data that suggests soy consumption has any adverse effects, even on infants. Soy not only has a long history of safe consumption in Asia, but millions of Americans have been fed soy formula (typically made with Soy Protein Isolate) since the 1970s with no serious health effects reported today, over 40 years later (Badger et al., 2002).