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 4th
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.
[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.
