Soy: Friend or Foe?
by Nancy T Angelini LMT, Clinical Herbalist
Soybeans, with 84.4 million acres planted, are a major commodity in the world marketplace, trading second to corn and leading in wheat and cotton production. Once limited to Asian markets, soybeans have become increasingly popular in the West, the USA included. Maintaining the popularity of soy products is an important consideration for investors of agricultural futures. The more evidence presented of soy as a “super-food,” the better the chances of selling the crop. Thus, the soybean is not exempt from special interest funding for research that glorifies its nutritional value and its possible contribution in healthy longevity.
While the research on soy is robust, it is not uniformly positive. Some studies laud soy as a remarkable super-food; other studies demonstrate the shortcomings and possible detriments to human health. There are studies that indicate there may be some benefit for bone and heart health, and other studies that reveal that soy is allergenic and may make it difficult for a woman to conceive.
The conscientious approach to solving the dilemma of soy as “friend or foe” is to study the research, to determine if the published science is without bias and done in a manner that presents an accurate picture of how soy, as a food, affects human health. I found that such a study was no small task, and although I make an earnest attempt to reach conclusions, there are so many variables and contradictory research that a definitive statement of soy being “friend or foe” was impossible for me to make.
Suffice it to say, determining if soy is “friend or foe” in the human diet is predicated upon many factors. As the saying goes, “the devil or the divine” is in the details and this is most true in the case of soy as dietary angel or devil. What I found that was fascinating to me was that, in order to resolve the question of whether soy is a “super food” or, conversely, a food filler to be avoided, was an understanding of the chemical and nutritional makeup of the soy bean. An understanding of the changes in these chemistries when it undergoes different food technologies is absolutely necessary. There is a difference between fermented soy, sprouted soy and unfermented soy.
Let’s Take a Look
Let’s take a look at the challenging aspects to soy first. According to the NAIAD, eight foods account for 90% of all food allergies in the US, and soy is one of the eight. We find that four percent of all Americans are afflicted with food allergies and of that four percent, less than one percent have soy allergies. That percentage may seem insignificant at first glance, but when we convert that percentage into numbers, we find that soy allergy affects tens of thousands of Americans.
In addition to being an allergen, soy contains particular compounds called isoflavones, which can have an inhibiting effect on reproduction in humans, if they are in their glycosidic form or inactive form versus their aglycone or active form. Early evidence-based research on the glycosidic isoflavones and the aglycone isoflavones are each showing different outcomes in human health. Some real examples are the outcomes on studies on Diadzein, which is the active form of Diadzin, which have excellent benefits, versus the studies on whole raw soy in the form of soy milk or soy flour, which have mixed outcomes.
In April of this year, a cross-sectional study, published in the International Journal of Women’s Health, found that there may indeed be a significant impact on woman’s ability to become pregnant with a diet that contains more than 40 grams of isoflavones in the form of soy in the diet. This finding may come as a surprise, since most of the Far East consumes between 25-40 grams of soy in their daily diet and the Asian population has high birth rates, seemingly unaffected by a diet high in soy. This study is an excellent example that the “devil or the divine” is in the details. Most of the soy that is consumed in Asia is fermented, including the tofu that is lovingly called “stinky tofu,” because fermentation makes the tofu odiferous. Most of the soy that is consumed in the US is not fermented.
To Ferment or Not to Ferment, That Is the Question….
The question then becomes, “what are the differences between fermented soy and unfermented soy?” Two studies demonstrate how soy is converted through fermentation.
Research published in 2013 in the Journal of Nutrition and Science of Vitaminology, demonstrates hypoallergenicity of various types of miso pastes. The longer the fermentation time, the lower the levels of allergens present in the final miso pastes.
A second study in 2014 also analyzed data on the effects of fermentation on soy. What is compelling about this research is the discovery of the conversion of the isoflavones from their inactive glycosidic form, to their active aglycone form. In 24 hours of fermentation, the glycosidic isoflavones were drastically reduced and the aglycone isoflavones were increased significantly. Thus, the scientific literature does indicate that the fermented soy is substantially less allergenic than non-fermented soy. That finding could be a relief for those who suspect some mild sensitivity to soy foods, but who are reading the articles touting the incredible benefits of consuming soy and would like to enjoy some of these health benefits.
There also is an indication that fermenting soy may actually increase its utility as a super food. In 2006, the Japanese Population-Based Osteoporosis Study was published in the prestigious Journal of Nutrition. The research demonstrated that natto, a fermented soy product, may help prevent the loss of bone through the effects of an activated isoflavone called MK7.
For while American research on the consumption of non-fermented soy food usually concludes that consumption confers mixed or very slight benefits, Asian research produces tremendous findings of multiple health benefits of fermented soy on human health. A further clue that the conflict may lie in fermented versus unfermented may be gleaned from a 2014 American study, which utilized the active state of one of the isoflavones and achieved alleviation of allergic encephalomyelitis by soy daidzein.
We Have Choices to Make Regarding Soy Foods
When we try to put it all together to make a final decision, the waters are still a bit murky. The wide-ranging
results from Asian compared to American studies on soy and its effects on human health have made making daily food choices a little “blurry.” I will endeavor to create some clarity around fermented soy choices.
Tamari and Miso are fermented soy foods. These choices are most definitely super-foods, and consuming them regularly confers a multitude of health benefits. American Tofu and soy-milk are unfermented soy. Although unfermented soy choices are not unhealthy, it may be best to consume these choices in smaller quantities and with less regularity.
Regarding the world wide scientific research on soy, we could say that the jury is still out about the proposed health benefits of soy, and if you have been diagnosed with a soy allergy, consumption would be contraindicated.
We could eat by example, using the wisdom of the Asian culture that has consumed fermented and sprouted soy for literally thousands of years as a staple of their diet and happen to be the healthiest, longest-lived peoples on the planet. Maybe this strategy is the one that inspires you to add this tasty legume to your diet for a more omnivorous experience, and the hope of enjoying a staple food that may offer some broadening of nutrition to your daily diet.
Nancy is a clinician of 27 years, and a 14-year educator and speaker in the Natural Products Industry.
Currently, National Science Educator for Source Naturals as well as the Owner and Clinician of Angel Clinic in Wenham, Massachusetts.
Compiles, writes and presents lectures on many health topics with a focus on alternative health using food, herbs and supplements to support wellness and longevity.