The Dangers of Soy

In the world of fitness and health, there are often many stumbling blocks. What is widely accepted as true one day may be scoffed at the next. Soy protein is a good example of this.

Soy, in recent years, has come to power as perhaps one of the most well-known sources of protein available. It is reasonably cheap, and soy has a wide variety of uses: it can be used in tofu, cereals, breads, candies (as soy lecithin or similar additives), and even in some protein powders.

What you may not know about soy may be harming you. The government makes the claim that "25 grams of soy protein a day as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease".

A few studies demonstrated how soy could enhance anabolic hormone, leading to less muscle catabolization and more muscular and strength development, and that it might just increase the levels of certain thyroid hormones, leading to stronger metabolism. Hearing that, what could I possibly tell you to make you believe that soy may be one of the worst things you can eat, especially if you are a male or an athlete, or, even worse, a male athlete?

Soy's negative aspects are mostly a result of two isoflavones (kinds of flavonoids), genistein and daidzein. These two isoflavones very quickly and easily bind to estrogen receptors. Estrogen receptors come in two types, alpha and beta. The alpha estrogen receptors are often associated with increased visible body fat, water retention, and other assorted nasties. Now, this may not sound too too horrible, yet. It may even be a good thing--these isoflavones are filling up the estrogen receptor sites, preventing other things from binding to them that could cause more damage.

There is a drastic effect that soy has on a very important hormone in the human body, especially the male body--testosterone. A definite link between soy consumption and serum testosterone levels has been discovered by researchers. One such study showed a 76% decrease in serum testosterone in men following the ingestion of soy protein over a short period of time. Of course, this level bounces back up after a little while, but what is that decrease in testosterone doing? For the most part, when there is a decrease in testosterone like that, estrogen becomes the more prevalent of the two, and that's when things start to get bad.

Since you might expect genistein to at least inhibit some of the estrogen receptors, it's scary once you have been informed that, in fact, genistein does not inhibit the estrogen receptors. Estradiol is another hormone that can present some problems for men in elevated levels. Normally, estradiol and estrogen balance out for the most part. But strangely, soy protein's effect with genistein seems to allow for both estradiol and estrogen to raise cumulatively higher than normal. Estrogen and estradiol, together, at the same time, pack a double-whammy for the male body. And there's also the fact that some evidence shows that genistein, unto itself, may increase estradiol levels slightly, though this is not the main source of the problem.

There is a good chance that the effects of the phytoestrogens found in soy (not to be confused with polyphenols--polyphenols are the good guys.) may have been horribly underestimated in the past.

But wait, there is more. And not just for men is this a problem--pregnant women can be impacted by the effects of soy as well.

When pregnant female rats were fed levels of genistein in proportion to the levels that an average soy consumption is in people who consume soy regularly, the offspring weighed significantly less. When young male rats were fed genistein, the generation of sperm decreased, along with body weight and testicle size. There is evidence to suggest that genistein may also reduce the urge to mate and reproduce.

And I almost neglected to mention that genistein was shown to cause necrosis in testicular cells in vitro. Yes, death. A component of soy has actually been shown to cause cell death in one of the most (if not the most) important organs in the male body.

The claim that the government loves to make about soy, the one about how it reduces the risk of heart disease? I looked into that a little further. What I found was a little surprising (but I've become a bit disillusioned about our government in recent years through finding out similar things as this) and pretty disturbing: soy protein has been shown in independent studies to reduce HDL (high-density lipoprotein) cholesterol. That's the good kind of cholestrol; LDL is the bad kind.

Beyond that, there is some evidence (though there hasn't been enough time to conduct conclusive studies) that our dangerous duo of isoflavones, genistein in particular, can induce or at least support the development of cancerous cells in the prostate--yet another big problem for guys.

If you are still reading at this point, I really hope you're beginning to question soy and the health industry as a whole. And don't deny that it is an industry--it is. A several-billion-dollars-annually-capitalism-driven industry. And soy is cheap to produce.

For the sake of argument, for the time being, let's assume that all of those studies are completely false. Not true at all. So, let's focus on soy protein for what it is--a protein. How is soy protein, just as a protein, as in in terms of how effective it is in rebuilding and growing tissue (especially muscle tissue)? Compared to casein (a slow-absorbing type of protein dominant in dairy products) and whey (a fast-absorbing type of protein derived from, well, whey) in terms of protein synthesis and protein breakdown, soy lost hands down.

A little technical speak: Studies show that genistein inhibits myoplast proliferation and fusion, based on dose.

This means that it actually decreases protein synthesis (the ability of your body to put together the amino acids your body takes out of the protein you eat), as well as the accretion of protein. The results were found at even the smallest tested dose. Theoretically, if one were to have a diet high in genistein, it could very likely adversely affect the development of normal muscle tissue, resulting in weak and underdeveloped individuals.

So, to summarize:

Soy increases estrogen and estradiol prevalence, and decreases testosterone prevalence. It may contribute to some forms of cancers. It is not effective nutritionally as a protein, and using it as a main source of protein results in muscular weakness and a fragile body. It is dangerous to sexual development even in utero. It does not yield the health benefits often toted by the government. The popularity of soy is directly resultant of its ability to be cheaply produced and easily marketed--lots of demand, lots of supply.

I strongly suggest that you look through some of the foods you eat, just check under the nutrition facts before you eat something, and see if anything soy-based is present. If something soy-based is present, just put it down. Share this information with everyone you know.