Many people believe that eating soy is a healthy alternative to eating meat. It is true that in some countries such as Japan, eating very small quantities of fermented soy has been shown to improve health in terms of lowering incidences of breast cancer, prostate cancer, osteoporosis, etc. But it is important to clarify that the soy these studies are referring to is different than nonfermented soy or soy that has been genetically modified (about 99% of soy in the US is GMO) and contaminated with more carcinogenic herbicides and pesticides than any other crop.
Next to wheat and dairy, soy has been found to one of the most highly allergenic foods—it may contain at least 30 allergenic proteins. The processing of soy results in lysinealine and nitrosamines and creates monosodium glutamates (MSG), which has been found to be an excitotoxin to the brain. Soy foods also contain high levels of aluminum that can also interfere with brain function.
Dr. Mary Enig and Sally Fallon have many arguments against soy (as noted below). First of all, soy was never intended as a food source, but as a way to fix nitrogen in the soil for crop rotation and as lamp fuel. It wasn’t until the second century BC that the Chinese discovered that cooked soybeans could be used with calcium or magnesium sulfate (a.k.a. plaster of Paris or Epsom salts) to make tofu. The use of fermented and precipitated soy food sources soon spread to other parts of Asia.
Dr. Enig remarks that “The Chinese did not eat unfermented soybeans as they did other legumes such as lentils because the soybean contains large quantities of natural toxins or ‘antinutrients.’”
What are the issues with soy? According to Dr. Enig:
- Soy foods may inhibit enzymes required for absorption of proteins. Eating soy foods along with small of proteins might help reduce this effect.
- Soy foods may contribute to blood clotting.
- Soy contains goitrogens, which may affect the thyroid.
- Soy is high in phytic acid, which can block mineral absorption; however, fermenting soy foods may help prevent this effect.
As if all of that is not enough, soy has also been found to affect brain health. How? Our brains are loaded with estrogen receptors, but when processed soy is consumed on a regular basis, the brain is denied this important hormone. A 2001 study of older men from Health Canada found that “Cognitive impairment was identified in 4% of men with the lowest tofu intake, compared to 19% of those with the highest intake; low brain weight was observed in 12% of subjects with the lowest tofu intake and 40% of men in the highest category.” Another article, “This Food Lowers I.Q. and Shrinks Brain” by Dr. Grisanti, DC revealed that tofu eaters had not only over 3 times the number of strokes, but 7 times the amount of moderate to severe brain impairment. If this doesn’t make you “rethink” tofu, maybe you have been eating too much of it!
I personally believe that non-fermented soy products such as soy milk, soy cheese, soy yogurt, soy ice cream, tofu, etc. are detrimental to health since they may block the utilization of proteins. On the other hand, fermented soy products such as tempeh, miso, and tamari have not been shown to cause these issues and may be a healthy choice.
Due to its high levels of phytic acid, soy can block the absorption of many minerals. If you must consume soy, research indicates that you will need to make sure that you also consume foods high in vitamins B1, B12 and D. Alternatively, consider a good multivitamin supplement.