Why Are You Afraid of Soybeans?

Why Are You Afraid of Soybeans?

Soybeans have been consumed by Asian cultures for thousands of years.  These legumes are so nutritionally complete that they sustained Eastern populations through drought and famine.  Like most legumes they are composed of protein, carbohydrate, fat, fiber, vitamins and minerals and thousands of plant-based compounds called phytochemicals that keep the plant from getting sick. When you eat these plants they prevent you from getting sick.

The protein of a soybean is unique in that it is the only plant-based protein whose amino acid composition mirrors the protein found in animals[1].  Soybeans are extremely heart healthy because they are low in saturated fat and are a good source of polyunsaturated fatty acids such as Omega-3 fatty acids, and roughly 40% of the carbohydrate content of soybeans comes from fiber.  The cardioprotective effects promoted by these macronutrients are derived from lower cholesterol levels.

All plants contain phytochemicals and one noteworthy compound found in soybeans is a phytoestrogen called genistein.  As its name implies it is an estrogen analog and therefore associated with an increased risk of breast cancer.  However, this is a gross misunderstanding.  Although genistein has been shown to stimulate the growth of a breast cancer cell line in test tube experiments clinical studies in patient volunteers have proven the opposite is true.  Not only does consumption of soy foods reduce the risk of breast cancer it also reduces rates of re-occurrence of breast cancer and increases lifespan in breast cancer patients.  Additional studies have shown that soy food consumption reduces rates of endometrial cancer and prostate cancer.

One reason why women in Asian communities enjoy a healthy body composition is related to their consumption of soy foods.  Estrogen is a hormone that helps to regulate fat storage so when levels are low, such as during menopause, foods containing phytoestrogens will help to restore that balance. These women also suffer from fewer menopausal symptoms (caused by low estrogen levels) and suffer less from bone loss.

Men also need not fear the mighty soybean.  No clinical studies have documented a correlation between soy consumption[2] and breast tissue growth nor do these foods interference with testosterone function.  Soybeans can be goitrogenic meaning that because they are so nutritionally dense the high mineral content may interfere with iodine absorption.  Therefore, men and women who suffer from an underactive thyroid should take an iodine containing multivitamin when consuming diets rich in goitrogenic foods.

A final area of concern for soybeans includes the topic of food allergy.  Soy protein is the 4^th most common food allergy and I’d like to think that it is related to the fact that 99% of the soybean crop in the US is genetically modified.  These soybeans[3] are largely used for the production of food additives such as soy lecithin, soy protein isolate and textured soy protein.  These foods should be avoided in favor of organic (non-GMO) edamame, soy milk, tofu, tempeh and other fermented derivatives of soybeans.

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[1] Soy is not a complete protein for infants as it needs to be supplemented with methionine.

[2] Consumption of soy supplements, which contain very high phytoestrogen levels, is not recommended.

[3] GMO soybeans are typically treated with pesticides such as glyphosate which is the main health concern for this crop.