Soy has become increasingly popular over the past few years with more people cutting dairy and meat out of their diets. Soy is full of nutrients and an excellent source of protein, and it serves as a great meat alternative for anyone wanting to cut down on meat consumption. With the increased popularity of soy, there has been some concern over how soy affects estrogen levels in the body, and what that means for overall health.

What is Soy?

Soy comes from soybeans, which have very high concentrations of isoflavones, or plant estrogen. This plant estrogen is similar to estrogen in the human body, but it’s a bit weaker. Because it is similar to human estrogen, the estrogen receptors in our bodies can bind to these isoflavones, which in theory could mess with estrogen levels in people. The main concern with these isoflavones and human estrogen is an increased risk of breast cancer or thyroid issues.

Despite these concerns, there is no definitive answer to whether or not soy negatively affects your health. Infants and women are at higher risk of being affected by this because of how estrogen affects their bodies. 

Research and Effects

A lot of studies have been done on animals, and in these studies, soy does negatively affect estrogen levels. Although this might seem like an indication of how it affects humans, it doesn’t really help much. Animals and humans metabolize food so differently that scientists can’t really use the animal study results to predict human results. Studies on isoflavones in humans have also been done, and these studies have shown no clear evidence that it increases the risk of breast cancer or thyroid disease. Studies have even shown that soy can help decrease your risk for breast cancer and cardiovascular disease. Some studies have suggested there’s a possible link between soy and increased risk of breast cancer in women who have a family history, but overall it’s unclear. Overall though, if you eat a “moderate” amount of soy, that is one or two servings per day, you should be okay.

As far as how it affects your thyroid, that is also unclear. There have been no conclusive studies showing that soy increases the risk of thyroid disease, but it could possibly affect medicine taken to treat hypothyroidism. Hypothyroidism is when your thyroid doesn’t produce enough thyroid hormone. People who have this can take prescription medicine to treat it, and people have thought that soy can interfere with the body’s ability to absorb this medicine. Again, there’s no clear evidence to support that soy significantly impacts the body’s ability to absorb the medicine, but it’s suggested that people that take meds for low thyroid wait at least four hours before eating soy just to be safe. 

Benefits of Soy

Although there is still research being done to determine if soy can negatively impact your health, the positive impacts are definitely clear. It has many nutrients in it including B vitamins, fiber, potassium, magnesium, and protein. It is an especially good source of protein because it contains all nine essential amino acids that our bodies get solely from the food we eat. Coming from a plant, that is especially awesome. It is often used as a meat substitute and cutting down on the amount of meat you eat can improve your health. Cutting down on the meat you eat also positively impacts the environment, which is an added bonus. Because of the estrogen present from the isoflavones, some women have used soy to treat menopause symptoms like hot flashes, but again, it comes as no surprise that definitive research hasn’t proven if this scientifically works or not. If you try it and it works, more power to ya.

As a soy lover myself, it can be a little scary to hear that it can negatively impact my health, but it’s also frustrating to know that there is no definitive answer for if this is true or not. Based on all of the research that’s been collected so far, it seems overall that a bit of soy in your diet definitely does more good than bad. I’m going to keep loving tofu until science tells me otherwise.