“Women consuming the equivalent of two cups of soy milk per day provides the estrogenic equivalent of one birth control pill… men who consumed the equivalent of one cup of soy milk per day had a 50% lower sperm count than men who didn’t eat soy. –Chris Kresser’s Paleo Code

Soy is often touted as a natural source of estrogen, but is it safe to use either for this purpose or as a food?

“About two ounces of soy products per day may be sufficient to ward off hot flashes and other symptoms” of menopause (Wright & Morgenthaler, Natural Hormone Replacement for Women over 45). However, as an estrogen source, it may not be the safest food option.

Soy is present in nearly every packaged and processed food in the U.S, in fact, the average American gets up to 9% of our calories from soybean oil alone. Compare this to about 2 teaspoons per day in China and 9 teaspoons per day in Japan, most of which is fermented soy, which neutralizes the toxins (like trypsin inhibitors that inhibit protein digestion and affect pancreatic function, and phytic acid, which reduces absorption of minerals like calcium, magnesium, copper, iron and zinc) that are present in most of the soy we consume in the U.S. (Chris Kresser’s Paleo Code)

Unfermented soy also increases our requirement for vitamin D and B12 (the opposite of fermented soy which provides these vitamins!), and disrupts endocrine function (potentially causing breast cancer and thyroid problems). Processed unfermented soy often actually contains carcinogens as well. (Chris Kresser’s Paleo Code)

It is not fully known how soy consumption may impact synthetic hormones, and it’s nearly impossible to avoid all soy since it’s in most of the food we consume, but it would be wise for most people to avoid eating the major processed soy foods like tofu, soy milk, and soy protein isolate. Fermented soy still contains estrogens, but is not as disruptive (or potentially carcinogenic) to our natural hormones, and is probably a safe food for most people.

I would generally recommend that people transitioning towards the masculine side of the spectrum avoid soy foods, and for those looking for natural sources of estrogen, there are many safer feminizing herbs and foods out there. For example, “flax contains substances called lignans, which have been shown to have estrogen-like qualities” (Wright & Morgenthaler). A few foods have small amounts of identical-to-human hormones [about 1-2% potency of human hormones] (Wright & Morgenthaler), including:
Rice, apples, date palm, pomegranate (estrone)
French bean seedlings (estradiol)
rice, licorice (estriol)

All information in this blog is for educational uses only. Always consult your doctor before taking any herbs or supplements, or changing or discontinuing your medications.

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