While research is ongoing, with some mixed results, there is good evidence that adding soy to your diet could improve bone strength. Soy foods are associated with improved markers of bone health and improved outcomes. Regular consumption of soy foods seems to have a positive effect on bone health, leading to the recommendation to include soy in a bone healthy diet. Several large studies of Asian women, who commonly include soy in their diet, found that women who ate more soy had a lower incidence of fractures.
Soy contains phytoestrogens called isoflavones. Isoflavones are very similar in their chemical structure to estrogen. There are two kinds of estrogen receptors in the body. Soy is a selective estrogen restrictive modulator. Soy seems to have a pro-estrogenic effect on bone but an anti-estrogenic effect on the breast and endometrial cancer. Soy preferentially binds to the receptors in human bone cells. So while estrogen as a pill may increase cancer risk, soy is associated with less risk. Soy milk compared to progesterone in one study found less loss of bone in the spine and lower fracture risk. Soy protein consumption is associated with a reduced risk of death from breast cancer.
Like most things in life, moderation is key and it’s not suggested you go crazy on soy. It’s probably best to not have more than 2 or 3 servings per day. I have seen some recommendations to limit to 4 to 5 servings per day. People with soy allergies should, of course, avoid soy. Also, when drinking soy milk remember that many soy milks have added calcium so you don’t want to drink too much of the calcium fortified soy milk as that would be the same as taking too much calcium as a supplement. You can find soy milk that has not been fortified with calcium but it is usually on the shelf with the other plant milks and not with the refrigerated soy milk.
Eat soy foods like tofu, miso (fermented soybean paste), tempeh, edamame, and soy milk. Soy protein concentrate which is an ingredient used in soy products generally doesn’t have a significant isoflavone content. Soy hot dogs, soy-based ice cream, and other processed soy products are lower in isoflavones and not a good way to get your soy. Soy sauce and soybean oil don’t contain isoflavones. Soy and isoflavone supplements do not appear to have the same positive effects on bone and the safety of long-term consumption of these supplements hasn’t been established so I don’t recommend taking them. In Asian populations, where soy consumption is associated with fewer fractures in postmenopausal women, they are eating whole soy foods and not soy protein concentrate, soy supplements or highly processed soy foods.
My three favorite ways to get soy into my daily diet include blending tofu into my smoothies, adding edamame to my salads, and enjoying a soy drink idea I got from Michael Gregor’s book “How not to die”. Dr. Gregor suggests mixing unsweetened, plain soy milk with dates, cinnamon, ginger, nutmeg, cardamon and cloves for a Chai like treat. It takes some work to get the dates blended in but it is worth it as you get a healthy, frothy, milkshake like treat. You can also add cocoa to it and drink it warm as hot chocolate.
If you don't already eat whole soy foods give it a try for the sake of your bones.
posted on 11/22/2022