This fascinating report in the UK Guardian Limited details some of the earliest evidence that soy can be harmful to your health.
One investigation began when multimillionaire lawyer Richard James became convinced that soy beans were killing his rare parrots.
Parrots do not eat soy in the wild, but a high-protein feed containing soy had been marketed as a new miracle bird food. When James fed it to his parrots, however, the birds became infertile, died, or aged prematurely.
Researchers initially thought that James must be mistaken about the cause, but when he financed an exhaustive study of soy, they found that soy contains toxins and disruptive plant estrogens, and could also damage the thyroid.
James's lobbying gradually forced governments to investigate. In 2002, the British government concluded that there was little evidence for the supposed health benefits of soy, and a good deal of evidence for its risks.
Soy's health claims are usually based on the low rates of heart disease and certain cancers in east Asian populations. However, Asians do not actually eat as much soy as has been generally assumed, and what they do eat tends to have been fermented for long periods. Fermentation considerably reduces the levels of dangerous isoflavones in soy.