Depending on whom you ask, soy is either a superfood which is rich in protein and other nutrients, or it is dangerous substance which will destroy your healthy. With so much conflicting information, what are you supposed to think about soy? To help clear the air, here are some of the most popular myths and misconceptions about soy and the truth behind them.
Myth: Soy contains isoflavones which can disrupt hormones
This is the claim about soy which incites the most fear, especially in men. Anti-soy advocates say that the isoflavones in soy, chemicals which are similar to estrogen, will cause estrogen-like effects and reduce testosterone levels. The fear mongers can often be heard saying that soy will cause testicular shrinkage, lower sperm counts, and, if given to infant boys, can disrupt development.
The soy isoflavones can have an effect on estrogen receptors, which is why soy is commonly recommended for treating symptoms of menopause. But here is where the anti-soy advocates get it wrong. They neglect to mention that there is more than one type of estrogen receptor in the body. Soy does not have any effect on the estrogen receptors which would cause problems like smaller testicles or reducing testosterone levels (source).
In a meta analysis of 50 treatment groups, researchers found that soy did not cause reduced testosterone levels. No study has ever found that soy causes reduced fertility, even when soy is given to infants (source). However, soy is associated with numerous benefits for men. An analysis of 14 studies found that soy reduces the risk of prostate cancer.
Myth: Soy causes breast cancer
This myth is also linked to concerns about soy isoflavones. Because soy acts on some estrogen receptors, people assumed that it would have the same effect as estrogen supplements (which does increase risk of breast cancer). But no study has ever found a positive link between breast cancer and soy isoflavones. In fact, it is the opposite which is true. Soy isoflavones may reduce the risk of breast cancer because they help regulate cell growth by blocking negative effects of natural estrogen. One study even found that soy reduced the likelihood of breast cancer reoccurring in women (source).
Myth: Soy depletes nutrients from the body
It is easy to understand where this myth comes from because soy does contain antinutrients. An antinutrient is basically anything which blocks nutrients from being absorbed. In the case with soy, the antinutrients are natural chemicals called phytates. Because phytates bind to certain minerals, they can prevent some iron, zinc, and calcium from being absorbed. The keyword to note here is “some”. You will still absorb a considerable amount of those nutrients, even with the phytic acid. The phytic acid in soy will in no way deplete nutrients from your body.
It is important to note that soy is very high in all of these nutrients which is supposedly blocks. So, while you might not be actually absorbing all 6.8mg of iron found in a cup of soy beans, you are still getting a lot of iron.
For people who are really worried about getting the most nutrients from their food, there are a few tricks for reducing phytates. Cooking and fermentation reduces phytates in soy. You can also add a splash of vinegar to soy beans while they are soaking to kill the phytates (source).
Myth: Soy prevents heart disease
Soy is considered to be a heart-healthy food. It is high in fiber, which can help reduce cholesterol. Soy also helps promote production of the natural chemical nitric oxide. Nitric oxide dilates blood vessels, which can reduce blood pressure. However, just adding soy to your diet isn’t going to prevent or treat heart disease. Unless you are also eating a healthy, well-balanced diet which is low in saturated fats, then the soy isn’t going to do you much good.