Soy is marketed today as a near-perfect health food. But it’s worth remembering where it started: in the 1913 USDA handbook, the soybean was listed not as a food at all, but as an industrial product. For most of its history it wasn’t eaten as a bean — it was grown to fix nitrogen and rebuild soil.
In traditional Asian diets, soy wasn’t consumed unfermented, because the raw bean carries natural toxins. Only after fermentation techniques developed did the familiar soy foods appear — miso, tempeh, natto, and soy sauce — and even then they were used in small amounts, as condiments alongside meat and fish broth, not as a staple protein.
The modern picture — soy milk, soy protein isolate, textured vegetable protein, and soy in everything from bread to baby formula — is largely a story of 20th-century food processing and marketing. A great deal of the favorable research has been funded by the soy industry itself, and in 1999 the FDA allowed a heart-health claim for soy protein. There’s even an unresolved question about whether soy protein isolate ever properly cleared food-safety (GRAS) review; historically it was approved for use as a binder in cardboard.
None of this means soy is poison in every form. Traditionally fermented soy, eaten in modest amounts, has a long track record. The caution is about modern, industrialized soy consumed in large quantities as a replacement for animal foods.
This article summarizes, in our own words, research compiled by Sally Fallon and Mary G. Enig, PhD (Weston A. Price Foundation). For the full original piece and complete citations, see their published work. Educational only; not medical advice. These statements have not been evaluated by the FDA.
