Health: Are soy products beneficial?
In recent decades, the production of soybeans increased at a very accelerated pace. Most of it is used to feed livestock, but there is also a strong push to human consumption from the food industry. Soy is being marketed as a health protein, soy milk is being promoted as a healthier alternative to cow's milk and so on.
The business of the food industry is based on converting the cheapest ingredients in products that people will buy. Alongside wheat flour, sugar and refined vegetable oils, soy is one of the cheapest options, therefore it is not difficult to understand the great interest behind it. Economic interest also influences science, since the industry sponsors the research done by the scientists. As soon as the industry is interested in marketing a particular ingredient, money pours down into researchers that can produce studies that make it look good on the eyes of the public and can convince the regulatory agencies.
This was this same strategy that was used in the past to demonize butter and promote hydrogenated fat, to sustain that sugar is not dangerous and so on. Even the tobacco industry used it to try to sustain that smoking was not a health hazard.
Although people in Japan were cultivating soy for millennia, they were consuming it almost exclusively in the form of fermented products. They would not eat the grains directly unless in case of a great famine. We tend to think that people from the past were stupid, but actually most of the time they where extremelly engineous in observing cause and effect and thus finding the best soutions for their problems. If people were doing something for centuries, there was probably a good reason.
In the case of soy, the main problem resides in the isoflavones, compounds that mimic the function of the hormone estrogen in the body. In women, they contribute to infertility and cancer, but the effects are much more expressive on men, causing the reduction on testosterone levels, which in turn can cause all kinds of problems, including persistent fatigue and apathy, brain fog, loss of muscular mass, weight gain, depression, sleep disturbances, enlarged prostate, infertility and so on. If you have a male body, especially over 40, soy products are definitely something to avoid. By consuming too much soy, a man can completely mess up with his body, up to the point of (literally) starting to develop breasts. The dangers outweigh any potential benefit.
Even if we would disregard the potential hormonal problems, soy is too rich in anti-nutrients, like phytates and saponins, that bind with other nutrients, preventing our body from absorbing them. Most of the soy cultivated nowadays is also genetically modified, which implies increased risk of allergies and the massive use of glyphosate.
Fermented soy products, like miso and tempeh are better, since the fermentation process breaks-down the isoflavones and anti-nutrients. From a health perspective, the consumption of small amounts of fermented organic soy products may actually be beneficial. People in Japan discovered this long ago, that's why they were consuming soy mainly in this way. An important observation however is that tofu is not fermented, therefore it should be avoided as much as other unfermented soy products, it’s not healthy at all. Much of the tofu sold nowadays is not even made out of soy grains, but from soy flour, that is already a processed product.