How Safe is Soy?
© Sally Fallon, M.A. & Mary Enig, Ph.D
Soybeans were one of the five sacred grains(1)in the Orient according to records dating back to before 1134. Agricultural reports speak frequently of using soybeans in crop rotation (to fix nitrogen and thus improve soil fertility) but there is no indication that soybeans were eaten until fermentation processes were discovered, sometime around 440 BCE. The first soy products eaten by people were tempeh, natto, miso, and shoyu tamari. And it was not until some centuries later (2nd Century BCE) that the process of making tofu was discovered.
While it is true that the people of the Orient have relied heavily on tofu as a source of protein for about a thousand years, this is not necessarily by choice or beneficial. The early Chinese did not eat soybeans, although they did eat other pulses, because they recognized the large quantities of a number of harmful substances which have been well studied scientifically. Some of the most detrimental are potent trypsin inhibitors which block the action of enzymes needed for protein digestion.(2) Soybeans also contain hemagglutinin, which causes red blood cells to lump together. Soybeans are also high in phytates, an organic acid which blocks the uptake of calcium, magnesium, iron, and especially zinc, and contributes to widespread mineral deficiencies.(3) In fact there are more phytates in soybeans than in any other grain, bean, or plant studied and these phytates are remarkably resistant to reduction techniques. Only a long period of fermentation will significantly reduce the phytate content of soybeans. The phytates and other anti-nutrients in soybeans are only partially deactivated during ordinary cooking and can produce gas, reduce protein digestion, and create chronic deficiencies in children.(4)
Another way to moderate the harmful effects of tofu and other unfermented soybean products is to eat tofu with meat or fish, as is traditionally done in the Orient. Vegetarians - especially vegetarian children - who eat tofu and drink soy milk as substitutes for meat and dairy products are at very high risk of loss of bone mass and severe mineral deficiencies. Oriental children who eat soy but no meat, eggs, or dairy often suffer from rickets, stunted growth, and lowered intelligence. Unfermented soy virtually destroys all zinc in the body; and zinc is critical for optimal development and functioning of the brain, nervous system and immune system.
