A few readers and friends (NB and MBS among them) have asked me to write a bit about my thoughts on soy, and the general health benefits/costs associated with the food itself, rather than only with the “meat substitutes” that are sometimes made from soy, and which I’ve written about previously.
A year or so ago, one of my good friends SF asked me for my views about soy, and this is what I wrote at the time: “As for soy, I guess I generally like to follow the Michael Pollan approach to food: if it came from a plant, eat it; if it was made in a plant, don’t. So, although I know there's lots of uncertainties about the health benefits/harms of soy, I guess I think that minimally processed, organic, non-GMO soy products are fine in moderation, until I get further evidence that I should stop eating them. But I have started trying to stay away from things like TVP, soy nuggets, and other super-processed sorts of soy foods (though locally-made soy milk and tofu stay on my good list). My go-to nutritionists (Marion Nestle, Andrew Weil, Walter Willett, and Michael Pollan [if he counts!]) give a thumbs sideways, thumbs up, thumbs sideways, thumbs sideways, respectively, I think.”
I mostly still stand by my thoughts of last year, but figured I’d elaborate a little for the purposes of this blog post, to at least provide some more resources on the views of those “go-to nutritionists” of mine.
Despite all the claims that soy is either a super-food (Complete protein! Lowers cholesterol! Lots of fiber! Prevents bone loss!) or the devil (Causes breast cancer! Prevents absorption of essential minerals! Suppresses thyroid function), it seems like it’s not really either, and that this general approach of thinking of food as medicine (or a harmful drug) is itself flawed.
So, whenever I have a nutrition-related question, I usually turn to Michael Pollan (author, activist, professor of journalism at UC-Berkeley), Marion Nestle (Professor of Nutrition, Food Studies, and Public Health at NYU), Walter Willett (Chair of the Department of Nutrition at Harvard), and Andrew Weil (Author and Physician, founder and Program Director of the Arizona Center for Integrative Medicine), in that order. Here are their takes:
From Michael Pollan, Sustainable Eating & Nutrition
Verdict: Thumbs Sideways
“Americans are eating more soy products than ever before, thanks largely to the ingenuity of an industry eager to process and sell the vast amounts of subsidized soy coming off American and South American farms. But today we’re eating soy in ways Asian cultures with a much longer experience of the plant would not recognize: “Soy protein isolate,” “soy isoflavones,” “textured vegetable protein” from soy and soy oils… Until those data come in [on the estrogenic effects of soy], I feel more comfortable eating soy prepared in the traditional Asian style than according to novel recipes developed by processors like Archer Daniels Midland. For more on soy see In Defense of Food, section III.”
From Marion Nestle’s What to Eat, Chapter 12.
Verdict: Thumbs Sideways
“At the moment, I find it impossible to make sense of the health debates about soy foods, not least because so much of the research is sponsored by industries [Cargill, Archer Daniels Midland, and USDA among them] with a vested interest in its outcome…They are just a food, one that you can choose to eat or not as a matter of personal preference. Soybeans and the minimally processed foods made from them make sense to eat but the principal result of the approval of the soy health claim has been the massive proliferation of processed soy products that can labeled with that claim.”
From Walter Willet, Eat, Drink and be Healthy as cited here
Verdict: Thumbs Sideways
Soy food may have a dark side "because estrogens play a role in maintaining normal mental function, and it is possible that too much antiestrogen in the wrong place at the wrong time could be harmful." But the bottom line is that he agrees that soy is a good alternative to animal protein, that it may lower the risk of heart disease and have other beneficial effects. “Just don’t overdo it,” he says. “Two to four servings a week of a soy-based foods such as tofu or soy milk is a good target.
From Andrew Weil: Rethinking Soy?
Verdict: Thumbs Up
“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…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.”
So, for now, I'm sticking with soy (of the non-GMO, organic variety), but in moderation. Other favorite nutritionists or guides or relevant research any of you have to offer?
Resources/Other interesting takes: