Is soy suitable for use in athletes and ordinary people? This was the question that has been bothering me for quite some time. I will give you a little bit of my background. It is something that I don’t include in my biography.
I started training with weights when I was 15. Back in these days the democracy was a new thing in my country, and the prices were going up just because as a new democracy we had to level our currency with the courtiers from the West.
The salaries however weren’t going up as fast as the prices were. So, at that time the most an athlete could afford to set aside for a protein supplement was only enough for some cheep grade soy protein concentrates.
Needless to say I must have eaten a truckload of soy protein back then. In those days I didn’t have the knowledge and I didn’t have the easy access to educational resources I have nowadays. Moreover, there wasn’t too much of a literature on this issue either (I now realize).
So, keeping in mind my early history in the sport of natural bodybuilding, my hunger for better understanding of the possible advantages and disadvantages of soy and soy proteins increased exponentially. I recently decided to do my usual digging and find the information I needed to help me put the pieces together.
When I started my search I didn’t even realize how hard of a task this is going to turn out to be. Being determined to once and forever find the truth I made the decision to continue no matter how much time this is going to cost me.
To keep this short here is what I did. I found quite a few articles and other published material but there were a few that stood out. Of course they all came from the two main camps: the pro-soy and the anti-soy. I thought I’d put these against each other in an imaginable, virtual dispute.
The main articles were: “Tragedy and Hype” by Sally Fallon and Mary G. Enig, “What About Soy?” by John Robbins, and “Think Soy is Healthy? Here’s Why it’s Not as Good as You Think” by Dr. Joseph Mercola.
Sit back and watch the dispute.
Argument: Cholesterol Lowering Abilities of Soy
Accusation: From the anti-soy camp: “…The published report suggested that individuals with cholesterol levels over 250 mg/dl would experience a “significant” reduction of 7 to 20 percent in levels of serum cholesterol if they substituted soy protein for animal protein. Cholesterol reduction was insignificant for individuals whose cholesterol was lower than 250 mg/dl.”(i) Note: Total cholesterol levels of over 200 mg/dl are considered high.
Defense: The argument of the pro-soy camp: “…The kernel of truth in Fallon and Enig’s statement is that soy consumption tends to bring down total cholesterol levels most in people whose cholesterol levels are high. But even people with normal levels benefit from eating more soy, according to dozens of studies, because it improves the ratio between HDL (good) and LDL (bad) cholesterol. This ratio is now recognized by the American Heart Association to be an even more important factor than total cholesterol levels in heart disease risk…”(ii)
Arbitration: In his article Dr. Mercola comments on the Robbins’s (pro-soy) argument about the cholesterol lowering properties of soy: “Robbins ascribes soy’s potential to lower cholesterol as beneficial. However, while this may be helpful in some, it can certainly cause disease in others. Low cholesterol does not necessarily imply good health. This is because we all need cholesterol and levels below optimal can cause serious problems. Much of the hype about cholesterol has been generated by self-serving research used to support the massive profit structure of pharmaceutical companies supplying drug-based “solutions.”(iii)
Argument: Phytic acid (phytates)
Accusation: “Soy and soy products are high in phyitic acid (phytates) – an anti-nutritive compound, which in large amounts blocks the uptake of some essential elements such as calcium, magnesium, copper, iron and zinc. The soybean has one of the highest phytate levels of any grain or legume that has been studied, says the anti– camp, and the phytates in soy are highly resistant to normal phytate-reducing techniques, such as long, slow cooking.”(i) Phytic acid decreases more readily the absorption of zinc that that of the rest of the minerals.
Fallon and Enig admit however that phytate levels can be significantly reduced through a long period of fermentation. Through a process called precipitation (as in tofu) the phytates are decreased as well but not as much as through a process like the fermentation.
Defense: J. Robins in his article: “…The phytic acid levels found in a plant-based diet including a serving or two of soy a day is not high enough to cause mineral absorption problems for most people eating varied diets (ii). Furthermore, Robbins says, when soy products are fermented – as they are in tempeh, miso, and many other soy foods – phytate levels are reduced to about a third their initial level. Other methods of soy preparation such as soaking, roasting and sprouting also significantly reduce phytate content.”
Arbitration: Here is what Dr. Mercola says on the comments of J. Robbins on the phytic acid content: “…This is one area where I disagree with Enig and Fallon partially in that the phytic acid in soy (and other plant products like beans, nuts and seeds) may be beneficial or detrimental, it just depends.
For men phytic acid is probably very helpful as nearly all adult males have excess iron as we never had menstrual periods. I personally take a phytic acid supplement to lower my iron levels. However, in menstruating women and children the phytic acid in soy can be a serious negative.
In his arguments Robbins correctly points out that fermented soy products have lower phytic acid than commercial soy products. However, he does so as to contradict Fallon and Enig, but this is exactly what they also state. They have no problems with fermented soy products and encourage their consumption.”(iii)
It should be kept in mind that phytates interfere mainly with the zinc absorption. Zinc is a major mineral in the athletes diet as it is involved in the steroid hormone production. It is also needed for the proper functioning of the brain and nervous system, protein synthesis, collagen formation, and blood sugar control.
Argument: Enzyme inhibitors (trypsin inhibitors)
Accusation: Among the anti-nutrient substances in soy and soy products there are the so-called enzyme inhibitors. What they do is they block the action of trypsin and other enzymes, needed for protein digestion. The anti-soy camp says: “these substances retain their configuration even when heated for long periods of time and can produce serious gastric distress, reduced protein digestion and chronic deficiencies in amino acid uptake.”(i)
Defense: Robbins acknowledges that “…there is a kernel of truth behind these charges,” but according to him these charges are “greatly overstated”. He continues “It is true that the protein in cooked soybeans is slightly less digestible than that found in most animal foods. However, when soybeans are made into soymilk, tofu, tempeh, and the other common forms of soy foods, their protein digestibility is enhanced and becomes similar to animal foods. Any negative impact on protein digestibility due to the presence of the enzyme inhibitors found in soybeans is rendered nearly irrelevant in such foods.”(ii)
Argument: Hemagglutinin and Goitrogens
Accusation: The anti-soy camp pulls the argument about the hemagglutinin content in soybeans. Hemagglutinin is a clot-promoting substance, which causes red blood cells to clump together. They admit however that hemagglutinin and the trypsin inhibitors (which they call ‘growth depressants’) become deactivated during the process of fermentation (miso, tempeh, natto). However, they warn: “In precipitated products (tofu), enzyme inhibitors concentrate in the soaking liquid rather than in the curd. Thus in tofu and bean curd, growth depressants are reduced in quantity, but not completely eliminated.”(i)
“Soy also contains goitrogens, they say — substances that depress thyroid function, a fact that has been known for at least 50 years.” Goitrogens lead to decreased Thyroid Hormone (TH) production, which in turn leads to increase in the Thyrotropin-Stimulating Hormone (TSH or Thyrotropin). High levels of TSH cause hyperplasia (increase in size) of the thyroid gland in an attempt to normalize thyroid hormone levels. This condition is known as Goiter.
Defense: In the pro-soy camp: “It is true that soybeans contain these substances. But there is little evidence that as a result soybeans represent a health danger to humans. Moderate amounts of soy foods have been eaten happily by entire civilizations for thousands of years.”(ii)
Argument: Genetically Modified Soy (GMO)
Accusation: Surprisingly it comes from the pro-soy side. Here is what J. Robbins says in his article “What About Soy?”
“There are legitimate questions about soy. One of the most recent, and most disturbing, stems from the fact that two-thirds of the U.S. soybean crop today is genetically engineered. These are beans that have been genetically altered to enable the growing plants to withstand being sprayed with weed killers, particularly Monsanto’s Roundup. For the technology to be commercially viable, the FDA had to triple the residues of Roundup’s active ingredients that can remain on the crop…
…According to Monsanto’s own tests, Roundup Ready soybeans contain 29 percent less of the brain nutrient choline, and 27 percent more trypsin inhibitor, the potential allergen that interferes with protein digestion, than normal soybeans. Soy products are often prescribed and consumed for their phytoestrogen content, but according to the company’s tests, the genetically altered soybeans have lower levels of phenylalanine, an essential amino acid that affects levels of phytoestrogens. And levels of lectins, which are most likely the culprit in soy allergies, are nearly double in the transgenic variety.
I find it fascinating that compared to regular soybeans, the genetically engineered beans have more of the very things that are problematic, and less of the very things that are beneficial. To my eyes, this is certainly another reason to eat organic foods whenever possible. The best way to insure that any soy foods you eat are not genetically engineered is if they are organically grown.”(ii)
Defense: No defense here!
Argument: Processing
Accusation: “…(Soy Protein Isolate) production takes place in industrial factories where a slurry of soy beans is first mixed with an alkaline solution to remove fiber, then precipitated and separated using an acid wash and finally neutralized in an alkaline solution. Acid washing in aluminum tanks leaches high levels of aluminum into the final product” (higher amounts of aluminum have been found in the brains of people with Alzheimer’s disease).
“The resultant curds are spray dried at high temperatures to produce a high protein powder… Much of the trypsin inhibitor content can be removed through high-temperature processing, but not all. …High-temperature processing has the unfortunate side effect of so denaturing the other proteins in soy that they are rendered largely ineffective.
Nitrites, which are potent carcinogens, are formed during spray drying, and a toxin called lysinoalanine is formed during alkaline processing. Numerous artificial flavorings, particularly MSG (Monosodium Glutamate), are added to soy protein isolate and textured vegetable protein products to mask their strong “beany” taste, and impart the flavor of meat.”(i)
Defense: None.
Argument: Isoflavones and Cancer Link
Isoflavones are the estrogen-like compounds, found in soy and soy products. They are often recommended for use from menopausal women for providing relief from hot flashes. 45 gr. of isoflavones (contained in just over 20 gr. of soy protein isolate) have shown to exert significant biological effect in women.
Accusation: “One hundred grams of soy protein, the maximum suggested cholesterol-lowering dose (and the amount recommended by Protein Technologies International), can contain almost 600 mg of is flavones (genistein and diadzein), an amount that is undeniably toxic. In 1992, the Swiss health service estimated that 100 grams of soy protein provided the estrogenic equivalent of the pill (birth control pill)…
…The logic that links low rates of reproductive cancers to soy consumption requires attribution of high rates of thyroid and digestive cancers to the same foods, particularly as soy causes these types of cancers in laboratory rats.”(i)
The following paragraph comes from the pro-soy article of J. Robbins: “…Although soy consumption on the whole reduces cancer incidence, there are questions about its effect on women who have estrogen-positive (ER+) breast tumors. These tumors are stimulated by estrogen. Might they therefore be stimulated by the weak estrogenic activity of the isoflavones found in soy? There is some evidence this may be the case, though there is also evidence that soy consumption favorably alters the metabolism of estrogen so that it is less likely to stimulate tumor growth. At this point, given the uncertainty, women with ER+ breast cancer should probably avoid eating more than three or four servings of soy a week.”(ii)
And again from the same article: “Although there is no firm evidence to demonstrate that ingestion of isoflavones has adverse effects on human beings, there is also no clear evidence that large doses are safe. When manufacturers of soy protein isolates and supplements recommend that people consume 100 grams of soy protein a day (the equivalent of 7 or 8 soy burgers), they are ignoring the unknown effects of overdosing on isoflavones. I believe it’s probably safer, until more is learned, to avoid concentrated soy supplements entirely.”(ii)
Defense: Nobody on this side again.
So, is Soy Protein Isolate (SPI) suitable for consumption from athletes?
Let’s summarize what we learned about SPI so far:
SPI, being non-fermented soy product, contains phytic acid (phytates). This can be okay for some men with significantly higher levels of iron. On the other hand we should keep in mind the fact that phytates reduce the absorption of other essential minerals such as calcium, magnesium, zinc and copper. Women, being chronically iron deficient are better off staying away from SPI supplements.
The defense failed to convince us that the presence of enzyme inhibitors in soy products and SPI is “irrelevant”. The enzyme inhibitors in SPI block the action of the protein digestive enzymes thus decreasing the rate and the amount of protein absorption. But isn’t this the main reason why bodybuilders would take protein supplements?
SPI contains hemagglutinin, a substance that causes erythrocytes (red blood cells) to clump together.
Goitrogens, also in SPI, cause thyroid gland enlargement.
Two thirds of the soy production is GMO (genetically modified), which means that the chances for a particular SPI supplement to be made of GMO soy are 66%. This is a quite disturbing number given the fact that GMO soy products contain less of some of the amino acids that make for the not even that good amino acid profile, and more of the anti-nutrients, already discussed above.
Nitrites, aluminum, lysinoalanine, and MSG (Monosodium Glutamate) can be found in the already processed SPI.
The amount of naturally occurring isoflavones in soy is about 50 mg per 25 gr of SPI. An athlete on a high protein diet, who provides some of the protein in his/her diet from SPI will easily consume at least two times that amount a day. This, according to the Swiss health service equals to a half (!) of an estrogen pill.
Going back to where I started I think I already had enough of all that for the rest of my life. However, I ought to mention that although the large amounts of SPI and SPC (Soy Protein Concentrate) I’ve consumed during my early years in this sport I personally haven’t experienced any noticeable side effects nor have I witnessed anybody to have experienced such.
I think I will stay away from SPI and all other commercial soy products including fresh green soybeans, whole soybeans, sprouts, flour, soy milk and tofu at least till the moment when they will be able to produce a SPI supplement, which won’t exhibit all (or at least many) of the negative effects, mentioned in the list above. The only soy products I will eat in moderation are the fermented like miso, tempeh, natto, fermented tofu, and fermented soy sauce, and only if they are organic.
Finally, as always I will leave it up to you to decide for yourself whether you will continue to eat soy products and supplement with soy proteins. I hope my efforts in gathering the necessary information will be sufficient for you to make an informed decision on your own.
References:
- Sally Fallon, Mary G. Enig; Tragedy and Hype
- John Robbins; What About Soy?
- Joseph Mercola; Think Soy is Healthy? Here’s Why it’s Not as Good as You Think
- James R. Mulinda; Goiter
- Joseph Mercola; Soy Bad, Soy Good: The Pluses of Fermented Soy