The soy controversy is alive and well in the West nowadays. The debate revolves around the phytoestrogens in soybeans.
These are in the isoflavones genistein and daidzein (names are not important, but if you need the data...) and are one source of phytoestrogens in our diet.
When you eat a normal amount of these foods, it should have no affect on your health.
While some people worry about the possible negative consequences of eating soy, where the actual soy controversy came from was a study that showed that they weren't positive that soy actually had health benefits.
Soy has come under heat about their phytoestrogens since 2006, when an American Heart Association review of a 10-year study found that soy protein may not reduce post-menopause hot flashes, may not be good for the heart, and may not prevent breast cancer, uteran cancer, or prostate cancer.
While there's so much concern over phytoestrogens in soy, soy foods and soybeans actually don't have the highest levels of phytoestrogens of any foods.
Concentration of Phytoestrogens (Highest at the top):
What the American Heart Association review said was that soy isoflavone supplements in food and pills is not recommended.
The review did say, however, "In contrast, soy products such as tofu, soy butter, soy nuts, or some soy burgers should be beneficial to cardiovascular and overall health because of their high content of polyunsaturated fats, fiber, vitamins, and minerals and low content of saturated fat. Using these and other soy foods to replace foods high in animal protein that contain saturated fat and cholesterol may confer benefits to cardiovascular health."
It seems the review simply found that soy supplements and pills cannot be proven to prevent cancers, heart disease, and post-menopausal symptoms. It also said that other soy products actually are beneficial.
The idea that estrogen helps trap fat in the body seems plausible. I guess we will have to wait until more definitive studies are done. I would like to see studies done on people who eat a normal amount of phytoestrogens in their diet.
In 2001, a review found that women who either had breast cancer in the past or who currently had it, were at an increased risk of tumor growth because of the phytoestrogens in soy products.
In 2006, there was another review that said that although soy may prevent breast cancer, that the isoflavones in soy need to be re-evaluated for people with a high risk of breast cancer.
A few studies have also found that eating soybeans lowers testosterone levels in men.
This lowering of the testosterone protects against development of prostate cancer. What hasn't been studied to a great degree is the affect of lowering testosteron levels.
Some people like to hypothesize that men will become feminized by eating soybeans and will lose their libido, which is completely absurd and not backed by ANY study.
Estrogen and testosterone are responsible for more than just sexual hormones and gender activity.
There is also soy controversy over infant formulas that contain soy. Some studies link the phytoestrogens in soy to intestinal problems, autoimmune disorders with the thyroid, and and other studies find that there are no adverse effects.
Some studies also present the idea that estrogen protecting and repairing the brain after injury may or may not be good for your health.
Another study on 3000 Japanese men between 1965 and 1999 found that the more tofu they ate, the higher the likelihood of brain atrophy.
There are also some issues with soy allergies. About 9% of children in the USA are allergic to soybeans.
Also, lab rats have developed pancreatic cancer from eating raw soy flour. No human studies have compared raw soy flour and panceatic cancer. Also, again, the rats were given enormous doses of soy flour, more than humans would ever eat. Also, once the soy flour was heated, it may not have been poisonous to rats.
Basically, the soy controversy comes down to a general lack of solid data on the risks of soybeans. Some say that it is not good for the body, and others say that the data cannot be substantiated with solid evidence.
Also, many of the studies are using extremely high dosages in their treatments and are using concentrated phytoestrogens that are taken from soybeans. The studies are not done with actual soybeans, where the concentration is much lower.
Concentrated amounts of virtually any substance are likely to be bad for your health.
Estrogen is no different.
Again, to go back to the study down in 2006 by the American Heart Association, soy supplements and pills are not good for you. We know this about supplements already.
You cannot expect to extract all the good stuff from real food, eat that, and still be healthy.
You must instead eat the good stuff to be healthy.
So, the soy controversy lives on. We'd love to hear what you think about soy, and you can also scroll down and read what our readers think of the soy controversy.