• Dr. Erica Oberg

ESTROGENS: SOY VS. ANIMAL PROTEIN

Updated: Jul 29, 2019

I’ve been getting a lot of questions recently about hormones and food. For example, “should I eat [or avoid] soy because it contains phytoestrogens?” “how much estrogen am I consuming if I eat conventionally raised dairy products?” “is additional estrogen good for my brain?” “does extra estrogen exposure add to my risk for breast cancer or blood clots?”

These are complex questions that have been investigated, with conflicting data, in many research studies. Studies of populations that eat lots of phytoestrogens (such as the high soy food consumption in Japan), women have lower risk of breast cancer and blood clots. However, when rats are given large amounts (30X a dietary amount) of isoflavones (an estrogenic component of soy), cancer risk goes up.  To quickly review the data, I turned to one of my favorite sources, Michael Greger, MD at nutritionfacts.org.  He’s a colleague from my research days and a trusted authority who does a much better job of blogging than me! Listen to his review here  His review of the research confirms – soy FOOD is an excellent quality protein that is more protective than harmful and the risk of true allergy to soy is < 0.5%. Further, it increases bone density!  So…unless soy is undigestible for you, the health benefit of a few servings per week is a good idea.

On the flip side of the estrogen conundrum is the question about how important is it to avoid the xenoestrogens in factory-raised cow products (dairy and meat). Again, Dr Greger has done the homework and his report is here. In short, the estrogens from cow products is at least 10-fold that of soy. Further, it is bioidentical and basically has no redeeming benefits.  Not to mention, the additional hormonal burden you are eating, such as high levels of the stress hormone cortisol that is present in animals under stress, such as cattle.

If you are looking for a way to incorporate dietary principles such as these in an easy, practical way, check out vegan Chef Madelyn at Zest. She makes and prepares vegan meals for San Diegans that are so delicious and nutritious, I frequently “prescribe” them for my patients!

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© 2020 by Dr. Erica Oberg, ND, MPH