Soy in medicine

The soybean is viewed very ambivalently in our society. On the one hand, there is great uncertainty about the use of genetic engineering in soybean production. On the other hand, soy products have the image of having particularly great health benefits.
Among other things, soy is said to have a cancer-preventive effect and to alleviate  menopausal symptoms  . The isoflavones found in soybeans, which belong to the group of secondary plant substances, are said to be responsible for this. Since they have a similar effect on the body as estrogens, they are also referred to as phytoestrogens.

Does soy help with menopausal symptoms?

Typical menopausal symptoms are hardly known among Japanese women with a traditional lifestyle. However, it is astonishing that Japanese women who emigrate to Western industrialized countries and adapt to Western lifestyles and diets suddenly   suffer from symptoms such as hot flashes . Due to the estrogenic activity of isoflavones, they are also increasingly used in this country as an alternative to classic  hormone replacement therapy  . For example, phytoestrogen preparations based on soybean or red clover extracts are available that promise relief from menopausal symptoms.

To get to the bottom of this promise, a series of studies were conducted that examined the effect of phytoestrogen preparations compared to  placebo  (dummy medication). In the majority of the studies, the results showed no or at least no significant decrease in the typical menopause symptoms.

Does soy prevent cancer?

It has long been known that hormone-dependent cancers such as breast and prostate cancer occur far less frequently in Asian countries where soy is part of a traditional diet than in western industrialized countries. However, this effect has not yet been demonstrated in studies with isolated isoflavones. There is even evidence that the growth of existing cancers could be promoted by the consumption of high concentrations of isolated isoflavones.

In addition to the consumption of soy products, other lifestyle factors are probably responsible for the different cancer risks in Asian countries. The time of delivery may also play a role. Mammary gland tumors were less common in female rats given isoflavone-rich food before puberty, but not when fed as adults.

Is soy good for the heart?

In addition to the points mentioned above, a reduction in the risk of cardiovascular disease through increased consumption of soy products is also under discussion. It is still unclear which ingredients are supposed to be responsible for this effect. However, it seems certain that it is not solely due to the isoflavone content.

Studies have shown that the use of intact soy protein, but not isolated isoflavones, reduces LDL cholesterol (so-called “bad” cholesterol),  serum triglycerides and, in some studies, increases HDL cholesterol (so-called “bad” cholesterol). “good” cholesterol). Soybeans are also said to have a beneficial effect on the elasticity of the blood vessels and the fluidity of the blood.

Conclusion

The soybean provides high-quality  protein , vitamins and  minerals . It has a favorable composition of fatty acids and contains valuable secondary plant substances, isoflavones. The latter in particular are said to have numerous health effects. This has led to an increase in isoflavone-containing dietary supplements being available on the market in recent years.

However, it has not yet been clarified whether isolated isoflavones can actually achieve the promised effects. Even the opposite effects have been reported.  The Federal Institute for Risk Assessment (BfR) therefore warns that the long-term use of isoflavone-containing food supplements is not without risk, especially for women in and after the  menopause . The soybean and products made from it are high-quality foods that are a good addition to our diet. However, the use of isolated isoflavones still requires critical examination.