Soy Pros and Cons

Last week I talked about the health benefits of soy. This week, you’ll hear the potential downside.

Monica Reinagel, M.S.,L.D./N
5-minute read
Episode #21

On last week’s show, I started talking about the pros and cons of eating soy. If you haven’t listened to that show yet, you might want to go back and listen to it now because we’re going to pick up where I left off.

In last week’s show, I talked about some of the health benefits of eating more soy. It’s promoted as a way to prevent heart disease, osteoporosis, breast cancer, and hot flashes.

But as soy’s healthy reputation has grown, there has also been an ever-louder chorus of nay-sayers who claim that soy is actually quite unhealthy. This week, I want to take a closer look at some of these charges. At the end of the episode, I’ll give you some recommendations about including soy in your diet.

As I explained last week, soy contains compounds called isoflavones, which are very similar to the hormone estrogen. In fact, isoflavones are also called phytoestrogens, which means “plant-estrogens.”

We’re still not entirely sure how phytoestrogens work in the human body but we think that they are beneficial. They can help compensate for low estrogen levels and, at the same time, help block the effects of excessive estrogen. In theory, this could help prevent a whole bunch of health problems, including hot flashes, osteoporosis, and breast cancer.

However, some fear that eating too much soy could potentially have harmful effects on men. Too much estrogen could theoretically affect fertility or sexual function.

In fact, scientists have found that giving large amounts of phytoestrogens to animals can indeed affect fertility. Keep in mind, however, that men have been eating soy and plenty of it for centuries in Asia and have not experienced population-wide fertility issues.

Could Phytoestrogens Harm Babies?

There are similar concerns about eating soy during pregnancy and giving soy formula to babies. The idea is that babies, both in the womb and out, are extremely sensitive to hormones and that phytoestrogens might affect their development. Again, I’ll point out that Asian women have eaten soy throughout their pregnancies and while nursing for centuries without apparent difficulty.

Soy baby formula is a newer development, however, and there is some reason for concern here. I think we can all agree that human breast milk is by far the optimal food for babies. Sometimes, however, breast-feeding is not an option. Soy formula can be a lifesaver for babies who have an allergy to cow’s milk. But, while there is no hard and fast evidence that soy formula causes problems, many pediatricians agree that it’s best not to give soy formula to babies unless you absolutely have to—just in case.


About the Author

Monica Reinagel, M.S.,L.D./N