Soy milk causes sterility in men

How healthy is soy really?

Soy and pregnancy

Hardly any alcohol, lots of vegetables and fruits - women who want to get pregnant pay attention to their diet. But there is some evidence that soybeans, of all things, can damage female fertility. Sheep suddenly became sterile in Australia in the 1940s and cheetahs in American zoos in the 80s. Isoflavones were to blame. In addition to soybeans, phytoestrogens are also found in some types of clover, chickpeas and the bark of plum trees. Zookeepers spoiled the cheetahs with soy food, the sheep ate a lot of clover.

Sure, people do not eat clover or only soy. But various studies show: Isoflavones can influence the female cycle. Women who eat a lot of soy have less follicle-stimulating hormone (FSH) in their blood. If very little or no FSH is released, the maturation of the egg cells can be disturbed. This was not the case in the present studies. It just lengthened the cycle of soy eaters - they ovulated a little later. "Soy as part of a balanced diet does not endanger female fertility," says Bettina Toth; the professor heads the fertility clinic at the Heidelberg University Women's Clinic.

Soy, a cholesterol killer? Not the bean

A traditional Asian dish with tofu, miso or sprouts contains between 10 to 25 milligrams of isoflavones. "Studies show that more than 100 milligrams of isoflavones per day can influence the function of the ovaries," says Bettina Toth. "However, due to the small amount of data, these numbers have to be viewed with caution; further research is needed here." One thing is certain: Phytoestrogens can affect female fertility. But to actually become sterile, you would have to eat a lot of soy. Moderate amounts are not dangerous.

The fairy tale of "superfood soy"

Soy was considered a superfood for many years. It sounded so good: In the mid-1990s, researchers at the University of Kentucky evaluated almost 40 clinical studies. The result: Anyone who eats 50 grams of soy protein a day, that is around 2.5 cups of tofu, reduces their LDL cholesterol by 12.9 percent.

The LDL cholesterol is considered harmful. If we have too much of it in the blood, it is deposited on the inner walls of the vessels. There is a risk of angina pectoris, circulatory disorders or a heart attack. Wouldn't it be good to put the bad cholesterol out of action with good soy? The problem: Current studies show little or no effect. A study confirmed that soy proteins reduce LDL cholesterol - but only by just three percent. Presumably the results have been misinterpreted in the past. Experts believe that regular soy eaters have better cholesterol levels because they eat less meat and pay more attention to their diet overall.

Conclusion: Soy can actually do harm - as a dietary supplement or in large quantities. "Restricting to a single food is never healthy - this of course also applies to soy", says Christine Behr-Völtzer, Professor of Nutritional Science, Dietetics & Prevention at the University of Applied Sciences in Hamburg. A balanced diet is crucial. So if you eat tofu every now and then, you take the positive effects with you: no cholesterol, lots of minerals and high-quality protein. And that's a lot.

The soy list

  • Soy milk: Popular cow milk substitute. The beans are soaked in water, ground, boiled and filtered. Important: The milk should be unsweetened.

  • Edamame: Is called "beans on the branch". The soybeans are harvested immature, not processed and cooked whole; they are high in fiber and protein.

  • Miso: In addition to soy, the paste also contains rice, barley and other grains. For this, beans and grains are steamed, then fermented.

  • Tofu: Curdled soy milk turns into a white, quark-like dough that is drained and pressed into blocks. Contains vegetable iron and vitamin B6.

  • Tempeh: Is firmer than tofu. Pre-cooked soybeans are fermented with a noble mushroom.

  • Lecithin: Will i.a. Obtained from soybeans and is found in many foods. Bread and baked goods, margarine, ice cream and chocolate - these are hidden sources of soy. Lecithin appears as E322 on ingredient lists.