In the last ten years, Soy has gone from an obscure food to the perfect food. Promoters of soy products would like you to believe that next to water, soy is probably one of the healthiest foods you can eat.
Based on soy’s extensive history of consumption in the Asian diet and the long lifespan of Asians as a group, soy industry has been successfully promoted soy as a family tradition and key to longevity and good health. However, careful scrutiny shows that the Asian diet is not one that is focused on soy at all. In fact 65% of the calories from a Japanese diet comes from fish. In China, 65% of calories come from pork. The total caloric intake from soy in the Chinese diet is only 1.5%. The amount of soy consumed in Asia averages only 2 teaspoons a day and up to ¼ cup in some parts of Japan. This is certainly not the large amount that we were led to believe. Furthermore, the modern processed soy protein food in the form of soy burgers and soy drinks found in supermarkets in no way resembles the traditional Asian soy. Soy consists of complex chemical and structural components. The main components are protein, essential fatty acids, as well as a class of compounds known as isoflavones. Isoflavones as a family include compounds such as genistein, daidzein, equol, and glycitein. These are also called phytoestrogens in that they have properties that are estrogen like but are derived from plants. The amount of genistein per day consumed in the average Japanese is only 10mg. Mega consumption of isoflavones such as soy burgers can bring the total daily genistein intake to over 200mg. Genistein is particularly harmful for people who have preexisting low or marginally low thyroid function. It’s antagonism to the thyroid hormone is well established. A daily dose of genistein as low as 30mg can affect normal thyroid function.
The soy isoflavone genistein and daidzein are similar to 17 beta-estradiols, but are 100,000 times weaker in estrogenic activity and are therefore weak estrogens. Although these isoflavones are weak estrogens, people who eat a lot of it can have their blood level of isoflavones as mush as 10,000 times higher than those who do not consume soy. Over time, high concentrations of isoflavones in the body can have a significant cumulative estrogenic and toxic effect, especially when they are exposed to organs that have sensitive estrogen receptors sites such as the breast, uterus, and thyroid.
The Chinese and Japanese have known about the toxicity of soy for centuries. Soy contains a variety of toxic chemicals, which cannot be fully metabolized by the body, unless it undergoes a long cooking, or fermentation process. Unfermented soy contains phylates, which acts as an anti-nutrient and blocks the body’s absorption of minerals from the gastro intestinal track. It also contains enzymes inhibitors that reduce protein digestion. Processed soy protein contains carcinogens such as nitrates, lysinoalanine, as well as a large group of anti-nutrients not found in traditional soy consumed in Asia. It also lacks calcium and causes a deficiency of vitamin D, both of which are not conducive for bone building.
The way soy is consumed in Asia is that it is allowed to be fermented first for a long time, from 6 months to 3 years. Only after extensive fermentation is soy being eaten as a condiment and not as a replacement for animal food. Fermented soy includes miso, tempeh, and natto and does not have the negative properties of unfermented soy. Miso is widely used as a soup base in Japan. Natto is a foul smelling fermented soybean preparation that has been consumed in Japan for over 1,000 years. Natto also has a high concentration of vitamin K2, a critical nutrient for bone building. It also has the extraordinary property of dissolving blood clots and keeping our blood vessels clear.
Modern processed soy products, including soy burgers and soy cheese are not the same as traditional Asian soy. They are by and large unfermented and include tofu and soy protein. These do not provide the same benefits as fermented soy products. A typical Japanese man eats about 8 grams (2 teaspoon) a day of soy that is mostly fermented as compared to the 220 grams (8oz) a western person in the form of a chunk of tofu and 2 glasses of soy milk, both of which are unfermented. Eating unfermented soy by a vegetarian actually increases the risk of mineral deficiency including calcium, magnesium, copper, and zinc. Unfermented soy such as soymilk is also the second most common allergen. 1% of the population is truly allergic to cow’s milk, and 2/3 of those will be intolerant to soymilk. Soymilk is also high in aluminum, because they are processed in large aluminum tanks. Studies have shown that 30gram of unfermented soy consumed daily can affect thyroid function and is strongly linked to a host of auto immune diseases such as Hashimoto’s thryoiditis as well as hypothyroidism.
There are some studies have shown that taking 35-60 gram of soy protein a day containing aromatase inhibitor genistein can protect the body against breast cancer. Other studies have shown that women eating soy had a higher incidence of changes in their bodily cellular structure consistent with per-malignant such as epithelial hyperplasia. Whether soy is beneficial or detrimental to those with estrogen dominance is highly controversial. The key to the puzzle is to understand that phytoestrogens are widely distributed in plants and have structures quite similar to the estrogen in our bodies. As such, they can bind weakly to our body’s internal estrogen receptor sites. Because estrogen is involved in the development of many unwanted disease including hormone sensitive cancers such as breast cancer, it is important to keep the estrogen level as low as possible in the body. Exposure to the estrogenic effect from soy, though weak, should be avoided in those who are at risk or , have symptoms of , or are in an estrogen dominance state.