Scrutinizing Soy

You’ve heard me comment here and there about Big Agra’s favorite legume, but I thought it was time to truly sit down with soy, stare it in the eye and get to the bottom of its real intentions.

Just so you know, we had an amicable exchange, and both parties came away from the table having learned a thing or two about open-mindedness and media frenzy.

It’s true, soy was once nutrition’s sweetheart. It could do no wrong (much like multi-grain anything these days). Within a shockingly brief period, it was thrust into the limelight, granted liberties it wasn’t ready for and didn’t, in all fairness, ask for. Its sudden fame propelled it into the likes of the dairy aisle, the barbeque line-up, even infant formula. Talk about big shoes to fill! Could anyone truly stand up to such phenomenal pressure and responsibility?

And so we find soy in its current circumstances, dissected by the health media, floundering, searching for a center long ago obscured, grasping for its authentic, legitimate role in nutritional balance.

All right, I’m ready to heave. Still with me? Just know that I’m completely serious about the media food frenzy, pun intended. Nutrition should be treated with more rationality and common sense than the parading line of fads and momentary cult worship. Maybe that’s what’s so satisfying about the primal diet: it doesn’t get any more basic than primitive.

Anyway, let’s get on with things and break it down.

Soy and Processing
The mantra applies here as well. All together now: Eat food, not food products. This doesn’t mean you have to forgo all forms of soy, but I’ll just say up front that food products with “the benefits of soy” conveniently added in just aren’t convincing me.

As I’ve said before, soy really needs some form of preparation before it’s safe to eat, and that in and of itself gives me pause. That said, minimally processed soy forms like fermented tempeh and miso as well as edamame seem like preferable options.

Soy processing isn’t a very comforting picture with acid washing and neutralization solutions, large and leaching aluminum tanks, and high temperature heating (rarely a good thing in the food world). And this doesn’t take into account the artificial flavorings, including MSG, that are oftentimes added to improve flavor. (Hmmm. When we say healthy tastes great, we kind of mean a food itself and not all the chemical crap added to it. No?) Finally, it’s vital to go organic when it comes to soy. Not only is it nearly all genetically modified, it has one of the highest pesticide contamination levels of any crop.

Soy and Cancer
We’re talking mostly about breast cancer here. The culprit in question is the group of soy isoflavones, plant hormones that mimics estrogen in the body. Some research has shown that isolated isoflavones, a.k.a. phytoestrogens, contribute to the growth of tumors in the breast, endometrium and uterus.

It essentially comes back to the whole foods question. The research has focused on the isolated isoflavones, particularly genistein, the most active of the soy isoflavones that activates cellular estrogen receptors, including those in breast tumors. Noted experts in the field have cautioned that research with isolated soy compounds does not necessarily carry over well to the effect of the whole food, even minimally processed soy flour. In other words, soy is healthier than the sum of its parts. Other studies have shown that the mix of phytoestrogens in soy, when taken together in whole soy foods, protect estrogen receptors and may partly shield them from the estrogen we take in with meat and dairy consumption (yup, bovine hormones even in organic). They can also possibly reduce the impact of the unequivocally insidious “xenoestrogens” found in chemical pollutants.

Add to this picture the analysis of cultural diet and disease trends. Though Japanese women regularly eat significant portions of soy (in forms like tempeh, edamame, miso and tofu), they have only 1/5 of the breast cancer rate that Western women.

Soy and Thyroid Function
Researchers are in general agreement that people with previously diagnosed hypothyroidism (underactive thyroid) should not take soy supplements. There’s not as much agreement, however, about soy and diet. The isoflavones in soy inhibit thyroid peroxidase, which produces T3 and T4, which can make a bad situation worse for those with diagnosed hypothyroidism or, as some suggest, help cause hypothyroidism to begin with.

It’s also important to note that soy isn’t the only food that has goitrogenic effects. Other foods in this category include (but aren’t limited to) cruciferous vegetables, corn and lima beans.

Soy and Mineral Absorption
Soybeans are high in phytic acid, which is known to block the body’s absorption of minerals such as calcium, zinc magnesium and iron. (Pertinent Insertion: grain-based diets have been shown to do the same thing.) Nonetheless, soybeans have the highest level of phytates. Fermentation is known to substantially reduce phytate levels, which is why you often hear that fermented soy forms are preferable. Other sources note that a meat or fish accompaniment to soy will reduce the effects of the phytates.

Bottom line…
Whole and fermented soy forms are clearly preferable. Personally, I wouldn’t bother with anything else. I know all of you soy milk lovers cringe when I say that. If you recall, I acknowledged a while back that organic and unsweetened non-GMO soy milk probably wasn’t a worse choice than regular cow’s milk.

I think there is something to the benefits of whole soy, and MDA has cheered and endorsed tempeh and miso more times than I can likely remember now. Not only do we endorse fermented food around her, but we appreciate the smart protein and blood sugar stabilization of tempeh.

Nonetheless, I’m still mindful of common soy concerns. I question the need for soy supplements, and I’m unequivocally against soy in infant formula (at least a whole entry unto itself!). For healthy adults, however, I acknowledge that soy can have a legitimate place in a well-rounded diet.

You’ve got my take now. What’s your thinking on soy? Shoot me a line.

Kanko* Flickr Photo (CC)

Further Reading:

Tempeh, Natto, Tahini Hurrah!

Spoutin’ Off on Veganism (Again)

Eating Fabulous: Soy May Help in Weight Loss

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About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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