5 Potential Dangers of Eating Soy

In the United States, soy is most commonly consumed as a replacement for animal products, as an emulsifier in processed foods, or in soy sauce.

You’ll also find soy in these common products:

• Soy infant formula, as a replacement for breast milk or milk-based formula for infants,
• Chocolate bars, processed foods, and some supplements as soy lecithin used to preserve shelf life and improve texture,
• Tempeh and tofu, as a replacement for meat,
• Soy milk, as a replacement for dairy milk,
• Condiments such as soy sauce or miso paste used to add flavor to traditional Asian dishes,
• Natto and edamame, as snacks or side dishes,
• Soy protein isolate, as plant-based protein powder, either used alone as a powder supplement or used in protein bars,
• Processed and conventional meat: even though soy is used as a meat alternative, it has also been used as a filler in processed meat and the diets of conventionally-raised animals are often supplemented with GMO soy feed.

Soy is controversial for a few different reasons, the most common being the isoflavones present in soy (see below for more information).

Soy is also one of the top 8 allergens in the United States–such a highly allergenic food invites controversy, whether founded or not, unto itself. Other controversial characteristics of soy include GMOs, antinutrients, and goitrogens.

Here is some more in-depth information about each controversial characteristic of soy. Keep in mind that there are no conclusive results on the dangers of soy. Whole soy foods or soy protein isolates will affect different people in different ways.

You also have to take into account your other risk factors such as your risk of heart disease, breast cancer risk, and other issues. Your gender and age may also make a difference! Premenopausal women and postmenopausal women may have different results from soy phytoestrogens.

Ultimately, it’s a personal decision as to whether or not you choose to consume soy or its isolates. The intention of this article is to make you aware of some of the potentials pros and cons, plus some ideas for how to consume soy with the least potential adverse effects.

Soy isoflavones, also known as phytoestrogens, are particularly concentrated in soy foods.

These natural compounds have a chemical structure similar to the human hormone known as estrogen. These phytoestrogens can attach to estrogen receptor sites in the human body and affect natural estrogen production and metabolism.

The possible manipulation of estrogen levels as a result of eating soy or soy products is a big potential danger of eating soy. The potentially harmful effects may be exacerbated with non-organic, highly processed forms of soy.

Having excess estrogen in the body can have an array of health consequences. These include, but are not limited to: breast cancer (though some research indicates a lower risk of breast cancer in women who consume soy), estrogen dominance, acne due to imbalanced hormones, endometriosis, male infertility (though more research is needed), and–in rare cases–gynecomastia (male breast growth).

Most of the soybeans in the United States come from genetically modified soybeans.

GMOs were only introduced to the public food supply in 1994 and there has been no opportunity to conduct long-lasting studies of the effects, safety, or long-term risks of GMO-containing diets.

Soy, like other legumes, is high in phytic acid. Phytic acid is an antinutrient, meaning it is the plant’s natural protective system that impedes the absorption of nutrients when consumed.

If you’re eating soy for the high levels of nutrients, some of them (like iron) are bound to antinutrients and are therefore unavailable to your body. Antinutrients can even bind to other minerals and vitamins present in your body, leaching them from you.

Soy contains naturally higher levels of goitrogens, which can interfere with proper thyroid function when consumed in excess.

Some healthcare practitioners may even advise people to avoid consuming soy up to 4 hours after taking thyroid replacement hormone. Better yet, people who have thyroid issues may wish to avoid soy products altogether.

As mentioned above, soy is one of the most allergenic foods. If you have a soy allergy, you may experience allergic reactions when consuming it.

If you have a lot of food allergies or have digestive or breathing problems after eating soy, you will likely need to avoid it.

Some health experts encourage the consumption of soy for its health benefits and as a replacement for animal protein.

Like most foods, there are both downsides and upsides to consuming soy. Keep in mind that when consuming soy, you’ll get the most nutrient density from organic, non-GMO soy in its whole form.

Here are some commonly perceived benefits of eating soy and the associated research.

Some research has shown that females who consume soy prior to and during pre-adolescent breast development have a lower risk for breast cancer later in life.

For instance, studies of Asian women from Asian countries seem to get a protective effect from consuming more soy products than women from the West.

It’s possible that these benefits may extend to males in the form of lower risk of prostate cancer, but more human studies and clinical studies are needed.

Though soy has been touted as beneficial for lowering high levels of low-density lipoprotein (LDL), the amount is indirect and not significant.

So, while there may be a small cholesterol-lowering benefit from eating soy, it is likely to be negligible.

Soy is particularly high in iron, calcium, potassium, phosphorus, and copper.

It’s also a plant-based source of protein, although you may want to avoid “fake” soy-based meats (see my related article on the potential dangers of plant-based meats).

If you choose to incorporate soy into your diet, it’s best to be sure you’re consuming it in moderation and that you’re getting high quality, properly prepared soy.

Ideally, the soy you consume should be:

• Organic: almost all of soy in the United States is genetically modified, but you can avoid both GMOs and heavy pesticide use by choosing certified organic soy.
• Soaked and sprouted: like all legumes and beans, the digestibility of soy can be improved through soaking and/or sprouting. This traditional method of preparation lowers antinutrients and makes it easier to digest (though a significant amount of the antinutrients still remain).
• Fermented: fermented soy products like tempeh and natto offer an impressive nutrient profile, probiotics, and increased digestibility.
• Whole: choose whole soy foods such as soy beans or tofu. Avoid soy protein isolate which is a highly processed food.