18 Dec 2014

Soy and Health: Urban Myth?

Category: HealthAdmin @ 12:23 pm

Is soy a wonder food or full of poison?

The Weston A. Price Foundation filed a lawsuit on December 16, 2014 against the U.S. Food and Drug Administration (FDA). At issue is that the FDA allows products to make health claims about soy protein’s effect on coronary heart disease. (Source: Citizens for Health, “Group Files Suit Over FDA’s Claim About Soy Protein’s Effect on Heart Disease.”)

The American Heart Association embraced soy in its AHA Science Advisory written in 2000, concluding:

…it is prudent to recommend including soy protein foods in a diet low in saturated fat and cholesterol to promote heart health.

In 2006, they reversed their position:

…the direct cardiovascular health benefit of soy protein or isoflavone supplements is minimal at best.

Another concern, especially among parents and others who work with children, is whether soy in infant formula may be harmful. Some of the reasons are discussed in the article, “Soy Infant Formula” at the National Institute of Environmental Health Sciences, a division of the National Institute of Health (NIH).

Soy seemed like a good target for research when the health of various Asian populations was statistically compared with US populations. Unfortunately, research on soy has lead to contradictory conclusions for cancer, heart disease, bone loss, thyroid disease and post-menopausal symptoms, among other things. Some studies show benefit, others show harm, while some conclude no effect either way, often for the same health condition.

There are various theories for the discrepancies:

  • Fermented vs. non-fermented: Asians tend to eat it in fermented form, while North Americans are more likely to consume soy milk and other non-traditional, non-fermented products. Fermentation may break down undesirable compounds in the soy.
  • How it is processed: Soy has protease inhibitors, which suppress key enzymes needed to digest protein, and phytic acid, which binds with essential minerals, making them difficult to assimmilate. However, proper cooking destroys many of the protease inhibitors as well as phytic acid, making soy relatively more digestible. Nevertheless, soybeans are beans, after all. Do they contain the same indigestible starches that so famously cause flatulence? I have never heard that soybeans are more digestible than other beans, only the reverse. If anyone has information to the contrary, I would love to hear it.
  • Different strains of soybeans: Most research does not distinguish between soybean strains. Genetically-modified (GMO) soybeans have some differences in their DNA, and thus in the proteins and other compounds coded by the DNA. The FDA has taken the position that GMO’s are foods similar enough to the natural organisms that they do not warrant testing for safety. Do some people react to the new constituents? The only way to avoid GMO soy is to eat organic, since GMO labeling in the US is not required. Most non-organic soy grown in the US is GMO, and soy, soy protein or other extracts are commonly included as low-cost ingredients in processed food. Another possibility is that one naturally-occurring strain could be worse for us than another.
  • What else is eaten: The traditional Asian diet is radically different from the current US diet. For example, I grew up on Fruit Loops, Sugar Frosted Flakes, Twinkies, Pop Tarts and applesauce raisin cake made with Crisco and sugar frosting, along with my meat and vegetables. I developed an intolerance to wheat, giving me digestive problems. This may have led to intestinal permeability (“leaky gut”), where some substances cross the intestinal lining that should not, entering the blood stream and leading to immune reactions that may make one susceptible to other food reactions, often including soy. Whereas many North Americans eat wheat with every meal, this is not so in Asia. The Asian diet also tends to include many more fresh and lightly-cooked vegetables, many varieties of which are rarely eaten here.

I have many more questions than answers here. Fortunately, we have plenty of food choices besides soy.

My recommendation? Do your own research, or at least go easy on the soy.

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