Whether in its original form or transformed into tofu and soy milk, soy has become an integral part of vegetarian and vegan cooking. For years, there have been more and more soy-based milk and meat alternatives in supermarkets.
The bean is known for its high protein content. According to the Federal Nutrition Center, this is about 40 percent in dried beans. Ready-to-eat soy products contain about 11 percent protein.
For a balanced diet, legumes are a very good way to replace the animal protein that is so important, says Stefan Kabisch, study doctor at the Berlin Charité Medical Clinic for Endocrinology and Metabolic Medicine. Anyone who eats different plant proteins can at least have a balanced diet as a vegetarian. However, vegans would need to add vitamin B12.
Soy offers many good things
Aside from protein content, the list of healthy soy components is long: B vitamins, minerals like magnesium, trace elements like iron, and unsaturated fatty acids, including omega-3 fatty acids.
However, the bean also contains substances that nutritionists consider in a more differentiated way. This includes isoflavones, which are similar to the female sex hormone estrogen.
For this reason, they are suspected of having a “hormonal activating effect”, as doctor Stefan Kabisch says. This means that they can bind to the same estrogen receptors in the body and trigger the same processes as estrogen.
So soy isn’t as healthy as you think? Healthy people don’t have to worry about normal consumption, says Kabisch. Due to their regulatory form, isoflavones are “most likely harmless, perhaps even helpful.”
Thyroid in danger?
This was also shown by long-term studies from Asia, where soy has been on the menu for much longer. By the way, isoflavones are also found in smaller amounts in other legumes like chickpeas, lentils, and beans.
And yet, soy is suspected of affecting the thyroid. According to the Kabisch doctors, isoflavones can block a specific enzyme in the thyroid gland. This enzyme is responsible for building active hormones from inactive precursors.
According to Kabisch, if this enzyme becomes inactive, hypothyroidism can develop. Because this effect is so small and not yet clinically relevant, he doesn’t see any health risk to healthy people with normal soy consumption.
However, the legume is not suitable for everyone. People with hormonal diseases such as breast cancer and metabolic disorders should have their diet reviewed by a doctor, says Nicole Schlaeger, team leader for healthy eating and nutrition education at the consumer center in North Rhine-Westphalia.
Basically, it advises against substituting dairy and meat exclusively for soy products. It is important to make sure there is a change and sometimes use oat or almond milk, ideally fortified with calcium.
In other cases as well, most nutrition experts recommend caution when it comes to soy. Soy milk is not suitable for babies and young children.