This is a Protein: This is a Carb – Part Three

This is a Protein: This is a Carb – Part Three

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Is Soy Dangerous?

It is time now for that closer look at soy protein. There is a lot of controversy surrounding the consumption of soy food products and, unfortunately in these days of purchased science, one-sided arguments, disinformation, and propaganda passing for objective information, it is hard to determine what the truth is. While soy marketing information offers only the positive aspects, the other side (perhaps motivated by the dairy industry?) offers only the negative material. As usual, the truth lies in between the two extremes.

The launch of the hypercritical material on soy products occurred under the title “Tragedy and Hype” in “Nexus” magazine, a periodical notorious for its conspiratorial material (some of which I agreed with). A response was issued sometime later, by the “Townsend Letter for Doctors and Patients”, a somewhat more respected source (though still of an unorthodox bent).

The articles critical of soy foods tend to refer mostly to rat and bird studies, extrapolating them to humans. Remember that rats don’t have “Thalidomide babies” (which was why that drug was given to pregnant women), so they are not a great substitute for humans in clinical trials.

Let’s look at one of the main arguments those critical of soy foods postulate: soy foods are high in phytic acid, a component that inhibits mineral absorption. One response is that the traditional use of soy in Asian cultures balances its mineral-depleting tendencies by fermenting it (miso, tamari, and tempeh), in order to neutralize phytic acid.

As well, when these cultures consume non-fermented soy foods, such as tofu, they eat it with seafood, or small amounts of meat. The extra minerals found in animal protein balances out the tendency of soy foods to inhibit some mineral absorption. Also, a diet high in meat can provide an excess of minerals to the body (especially iron and sodium), which eating some soy foods can help to keep in check.

Now, interestingly, there is an anti-cancer product on the market called IP6, a well-researched substance that is derived from phytic acid. This illustrates that, if we are looking only at one property of a substance, and only one aspect of that property, we are not going to get a complete picture.  Furthermore, the fact is there are many benefits to consuming phytic acid, all scientifically well-established. (For more on the subject, see this newsletter.)

Yin and Yang

In Western medicine, soy is considered “estrogenic” (raises the female hormone, estrogen) whereas in the Macrobiotic (Japanese) tradition it is considered “yin,” or “cooling,” in nature. Animal protein (meat, especially) by contrast, is known in the West to raise testosterone (male hormone) levels, and in the East is determined to be “yang,” or “heating”, in nature.

We can see here that soy is a good balance to a meat-based diet. Not only does it counteract the tendency of meat to raise testosterone, and over-heat the body system, but it can also reduce cholesterol levels (this is well established, scientifically), another side effect of high animal protein intake.

So, if one has high blood pressure, or hot flashes due to menopause, both of which are “heated” conditions, soy is an appropriate way to help cool the body system. If you were pale, weak, and cold most of the time, your condition, already too cool, would be worsened by soy foods (and “cooling” herbs such as North American ginseng), but would be improved by more “heating” foods (and herbs, such as Korean red ginseng).

Thus, while soy may aggravate PMS due to its estrogenic nature (most PMS is due to excessive estrogen levels), it could aid menopausal symptoms, a condition caused by low estrogen. “In good studies, soy reduces the frequency of hot flashes 20 to 30% more than a placebo does”, reports M. Kur-zer, director of the Healthy Foods, Healthy Lives Institute (University of Minnesota).

The fermentation of soy food will eliminate its estrogenic properties, so, again, miso, tamari, and tempeh, do not carry any of these concerns. I have however observed that the new generation of “fermented soy protein” isolates appear to be even more estrogenic than unfermented soy foods, and should only be used to raise estrogen levels. (Whatever their fermentation process is, it does not eliminate the estrogenic properties in the same manner that traditional fermentation processes do in the case of miso, tamari, and tempeh.)

The real danger of excess soy consumption occurs mostly among vegetarians, and those who use it as their primary source of protein. To have the majority of one’s protein derived from a “cooling” source could, over time, create an imbalance in the body.

Traditionally, all cultures that consume soy foods also consume some animal protein. On the other hand, a diet based dominantly on animal protein could also create an imbalance, by being too heating. That is unless you lived in the Arctic, which, being very cold, requires many thermal units of energy and heat (calories) in order to survive. Vegetarian cultures tend to exist mostly in hot climates, since they can get away with less calories (and “heat”).

Other arguments against the use of soy include the fact that soybeans contain enzyme inhibitors. These are also found in any raw seed or nut (the reason Eastern systems advise against consuming them raw), and are neutralized by simply cooking, fermenting, or sprouting the food (or just soaking in water for 24 hours, in the case of seeds and nuts).

It is true that soy foods dampen thyroid function and, considering the vast majority of Westerners have poorly functioning thyroids, it is important that people are aware of this. Again, traditionally, any culture that consumes soy foods also consumes seaweed, so it is important if you use soy foods regularly, that you also ensure an adequate iodine intake.

This means eating seaweed regularly, or at least obtaining the Recommended Daily Allowance of iodine (150 mcg) through nutritional supplementation. While this amount of iodine is too low for optimal thyroid health (the Japanese get 20 times this much), it should be sufficient to offset the thyroid-inhibiting tendencies of soy foods. (For more on this subject see this newsletter.)

Science on Soy and Cancer

Contrary to the warnings against using soy foods for those with hormone-related cancers, that some doctors advise, the phytoestrogens found in soy can actually help prevent both breast and prostate cancer.  Evidence from observational studies “shows a statistically significant association between soy consumption and decreased prostate cancer risk”.  (Source)

Other such studies “show that among Asian women higher soy consumption is associated with an approximate 30% reduction in risk of developing breast cancer. However, evidence suggests that for soy to reduce breast cancer risk consumption must occur early in life, that is during childhood and/or adolescence.”

Contrary to the old idea that soy foods might increase the likelihood of high-risk women developing breast cancer, or worsen the prognosis of breast cancer patients, “extensive clinical and epidemiologic data show these concerns to be unfounded. Clinical trials consistently show that isoflavone intake does not adversely affect markers of breast cancer risk, including mammographic density and cell proliferation. Furthermore, prospective epidemiologic studies involving over 11,000 women from the USA and China show that postdiagnosis soy intake statistically significantly reduces recurrence and improves survival.”   (Source)

What to Look for When Buying Soy Foods

Certainly, there are arguments to be made against consuming soy products that are non-organic, particularly since almost all non-organic soybeans are genetically modified. And this particular modification allows the plant to take more of the pesticide “Round-up” than the last generation of soybeans. Surprisingly, the company that genetically modified the soy-bean also manufactures “Round-up,” which sounds like a win-win proposition—for someone.

Aside from ensuring our soy foods are organic, there is another thing to be aware of regarding tofu. A friend, who worked at a tofu production facility, informed me there is a distinction in quality between tofu made with calcium sulfate as a coagulant, and those that use magnesium chloride. The calcium sulfate (a cheaper ingredient) in tofu is believed to impede mineral digestion, while the magnesium chloride encourages it.

This information led me to recall a Hawaiian study, which linked tofu consumption to Alzheimer’s disease among immigrant Japanese. Recently, it has come to my attention that soybeans will pick up aluminum if it is in the soil (or the cooking pot), and we know that high aluminum levels in the brain are linked to Alzheimer’s disease.  (Source)

It turns out that both magnesium and aluminum compete for the same receptor sites in the body, therefore, it is plausible that using magnesium chloride in tofu may forbid the body from up-taking any aluminum that may be found in such products.

(Further to the above study, “this same study concluded that the men who ate tofu had a 65 percent lower incidence of prostate cancer than their anti-soy counterparts”.)

In fact, if a causal effect existed between soy consumption and Alzheimer’s disease,  then we should see a  greater incidence of Alzheimer’s in Japan, where tofu is eaten regularly. But, this is not the case: Japan has some of the lowest Alzheimer’s and demetia rates in the world.  (Source)


Contrary to claims made in the Nexus article (and others of its persuasion), there are no studies on humans that show negative effects of soy foods on offspring. I personally raised three healthy boys to adulthood on a relatively high soy diet, and their mother consumed plenty of soy foods before conception, and during pregnancy. Our diet was essentially Macrobiotic, which is dominantly vegetarian, going as high as fish on the food chain (and including eggs). I personally have used soy foods, almost daily, for the last 40 years, with no obvious ill effect, so far.

My advice to clients concerning soy is this: have no more than one serving of “cooling” soy foods per day (edamame, tofu, or soy milk) unless you have a “heated” condition. Have all the miso, tamari, and tempeh that you like.

I tend not to recommend soy protein isolate powder any more, since it is a mass-produced slurry, and seldom available in an organic form. Even though many of the studies that show health benefits were done with soy protein isolate, I see it as a supplement rather than a food. Say what you want about tofu, at the very least we know it has been safely consumed for centuries, by men, women, and children.

The caveat is; how well do you digest soy? Generally, if you eat soy foods and get gas and/or indigestion, it is not beneficial for you. Another clue is your blood type. Types A and AB tend to digest it efficiently and gain the greater benefit. And, trust your taste buds. I like tofu and soymilk, as well as the fermented forms, and I feel satisfied after eating them. My body likes soy foods and digests them well, so I shall continue to enjoy them.

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