In Italy, like and more than the rest of the West, there is an increase in the consumption of foods based on soybeans : tofu, soy milk, soy yogurt, soy cheeses, including spreads, etc. Some people have written to me in the past to find out if these foods are bad, with particular reference to the role of soy isoflavones, and whether or not these isoflavones cause hormonal problems, especially in women, i.e. an excess of estrogen. The answer is controversial, I will try to simplify. In fact, to consider soybean foods as harmful based on their isoflavone content, we would have to use them daily ., for example in vegetarian and vegan diets, soybean products are often abused. If I eat soy and soybeans every day, probably yes, I should also worry about the excess estrogen caused by isoflavones. If I eat them once a week, if I eat tofu once a week, then I can safely avoid being alarmed. The problem, as one study made clear, is excess. If we have a varied diet and don’t drink soy milk every morning, then eat tofu for lunch, then we shouldn’t worry about it.
Personally, I no longer eat soy or soybean products: I am trying to eliminate all those foods that help suppress the proper functioning of the thyroid and cause overweight, but being overweight is apparently the dumbest thing to worry about, at least hearing about personalities like Ray Peat , the well-known endocrinologist who for years fought against the industry that uses both soy and polyunsaturated fatty acids in products. widely consumed and in the forage of intensively farmed animals.

Yes, but the scientific data? Any studies? There are many: an important meta-analysis established that soy isoflavones do not cause hormonal problems in men (on testosterone, for example, and fertility) , but the authors warn that it refers to a period of consumption of less than six months. The most complete research is in my opinion this from 2012,  where experts say that, given the conflicting results of previous research, new studies were expected that for example would consider larger samples, make differences between the types of soy consumed, and especially they considered a period longer than six months.

So the problem is upstream: if we already eat baked goods that contain polyunsaturated fatty acids, we are already doing something that damages our thyroid, as I explain here . At that point, adding soy products means giving our thyroid the classic coup de grace . Consider not just soy milk or tofu, but soy lecithin found in so many confectionary products. It goes best for fermented foods: miso, tempeh, natto, Japanese soy sauce. But how many people eat these foods? 
In short, I don’t like being alarmed, but personally I don’t eat soy products anymore just as I don’t eat products containing vegetable oils anymore, apart from extra virgin olive oil and coconut oil: both of these things should be avoided in order to have a healthy metabolism.