Whenever you read or hear about soy you’ll know about its benefits and risks. Unfortunately, there’s a lot of misinformation going around. So is soy good or bad? Below are some of the common fears surrounding soy and the truth about them.
There are many concerns surrounding the consumption of soy and soy-based foods. The concerns stem from the fact that soybeans are very rich in isoflavones, which are plant chemicals that cause estrogen-like effects. In particular, there’s a common fear that eating such foods may increase the risk of breast cancer, especially estrogen receptor-positive cancer.
However, epidemiological studies have found no association or link between soy and breast cancer. In fact soy may even have a protective effect.
Most of the concerns surrounding soy foods have to do with their impact on the many bodily systems influenced by estrogen. Breast cancer, especially estrogen receptor–positive breast cancer, is a primary concern. Despite acting like estrogen, isoflavones also have anti-estrogen qualities. They can reduce the binding of estrogen to receptors. Soy can also protect from cancer thanks to its antioxidant and anti-inflammatory properties.
Studies on mice and rats showed that high doses of phytoestrogens (which are found in soy) impaired the male rats’ ability to procreate. However, this is not really true when it comes to humans simply because rodents and men do not metabolize soy isoflavones in the same way.
It is important to note that there were cases in which men experienced sex hormone changes after consuming very high doses of soy. Yet when their consumption decreases, the effect was reversed.
In other words, it’s totally safe for men to consume soybeans and soy products as long as they don’t overdo it.
One study conducted by Sathyapalan and colleagues showed that the phytoestrogens found in soy can inhibit thyroid function. However, “only very high doses of soy phytoestrogen supplementation may induce clinical hypothyroidism in a minority of patients with sub-clinical hypothyroidism” MD Jorge Mestman says.
As a general rule it’s safe to eat soy. Those being treated for hypothyroidism should be more careful and avoid consumption of soy because it decreases the absorption of thyroid hormones replacements.
There’s some concern that soy ivoflavones can affect children’s growth and development because of its estrogen-like properties. Yet so far no studies were able to show such negative effects in babies who were fed soy milk and soy based formulas. These children and children who were fed cow milk based formulas function normally and they show normal growth and development.