Q & A Library
Your last articles about soy were written almost two years ago. Since that time, there appears to be more evidence that soy should be avoided with the exception of properly fermented products, like miso and tempeh. Have you changed your opinion?
Answer (Published 3/12/2004)
I'm aware of Internet paranoia on the subject of soy and the contention that only fermented soy is safe to consume. That is simply not true. Some of the best forms of soy - edamame, tofu and soy nuts - are unfermented and are much more likely to help you than hurt you.
Claims that unfermented soy foods (such as tofu and soy milk) contain toxins that block the action of enzymes needed to digest protein, and that these toxins cause pancreatic enlargement, cancer and stunted growth in animals are misleading. While soy does contain substances (trypsin inhibitors) that may adversely affect the pancreas in animals, there's no solid evidence that they cause similar problems in humans. Furthermore, trypsin inhibitors are found in all of the vegetables of the cabbage family as well as in beans other than soy.
Other concerns about soy safety focus on the following issues:
All told, based on the evidence to date, I see no reason to worry about eating soy foods, whether fermented or not. I still recommend consuming one to two servings of soy per day, an amount equivalent to one cup of soy milk, or one half cup of tofu, soy protein (tempeh) or soy nuts.
Andrew Weil, M.D.
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