A simple Google search will leave you confused about whether eating soy is good for your heart and blood vessels or as evil as Twinkies.
Ok…so nothing could be as evil as Twinkies.
But what IS the deal with soy? Is it good for us, or does it vaporizes the thyroid, cause breast cancer and stimulate teenage boys to grow Dolly Parton-esque boobs?
As someone who reads through hordes of medical literature, I can tell you that the evidence overwhelmingly points to soy as being very protective for our health. I don’t even recall coming across any negative studies on soy, and this is a topic I always keep my radar screen open for. Interestingly enough, all of the articles and blog posts on the Internet demonizing soy seem to point out the evils and then, in fine print, begrudgingly note that soy might be ok if it’s not processed and non-GMO.
When pressed, the naysayers agree that soy is part of a healthy lifestyle once those two factors are addressed. So why not address these two requirements right out of the gate? I can’t figure that one out myself. Regardless of other opinions, I continue to promote soy as part of a healthy lifestyle. And, as noted, this means no processed soy (as in veggie burgers, veggie dogs, textured vegetable protein, etc..) and non-GMO.
Also important to note is that soy contains protective compounds referred to an isoflavones, specifically daidzein and genistein. By themselves, these compounds have protective effects. Beyond this, if someone has the right blend of bacteria in his or her gut (like Asians raised on soy) these bacteria in the gut convert another class of compounds (lignans) into an even more potent compound called enterolactone. This benefit may be destroyed by antibiotics.
You can see that it’s not all that simple. The take home message is that soy is, in almost all circumstances, very good for you, so long as the above 2 criteria are met. And you’re not allergic (not really all that common unless you were inundated with soy over a long period of time), and in some susceptible people it might cause some thyroid problems.
All of this brings me to this particular study looking at the effects of genistein on certain cardiovascular markers. Participants to 54 mg/day (just under a cup’s worth of tofu) for 6 months, along with a Mediterranean-style diet. Here’s what they found:
- Blood flow (as measured by flow mediated dilation at 50 seconds and peak FMD) improved.
- Decreases in total cholesterol, triglycerides and homocysteine.
- Descreases in visfatin (a hormone produced by fat cells that drive diabetes and inflammation).
- Adiponectin (another fat-derived hormone, but one that protects against diabetes and inflammation) levels were increased.
- The participants on the genistein experienced no more side effects nor discontinued the study.
Overall, this was a very positive effect on the health of the blood vessels. Contrast this with the negative health effects of poor quality, abused, commercially grown beef. Complete opposite ends of the vascular health spectrum.