Soy milk, tofu, soy veggie burgers, and other soy products are touted as healthy alternatives to meat and dairy. Many vegetarians and vegans rely on soy as a main source of protein because of its proclaimed health attributes. However, even if you are a meat-eater, you are likely eating a substantial amount of soy every day.

Much like corn and wheat/gluten, soy pervades the American diet and is in practically everything. You will find it in milk substitutes, dressings and sauces, chocolate, body products, cakes, crackers, and infant formula. Soy lecithin is an emulsifier that is added to many processed foods such as chocolate, baked goods, and bottled smoothies. Soybeans are also used as animal feed, therefore soy is present in your meat products if you aren’t buying grass-fed or pasture-raised.

I don’t consider soy a health food, and here are five reasons why:

1. Over 90% of U.S. Soybeans are GMO

“Genetically modified organisms,” or GMOs, are plants and animals that have been created by combining DNA of different species in a way that could not occur in nature or by traditional cross-breeding. Significant evidence is beginning to surface that GMO foods promote disease.

Over 90% of soybeans in the United States are GMO, and due to cross-pollination by wind and insects, the remaining 10% of non-GMO soy isn’t guaranteed to be non-GMO.1

Assume that all soy in the United States is GMO, and that buying only organic soy isn’t necessarily going to protect you.

2. Soy Contains Isoflavones

Soy contains chemical compounds called “isoflavones” that mimic estrogen. Estrogen occurs naturally in your body and remains in careful balance with your other hormones. Too much estrogen causes reproductive difficulty in both men and women and has been implicated in cancer development.

The estrogen-like compounds in soy have been shown to increase tumor growth in animals, 2 leading researchers to speculate that they may have a harmful effect on a developing human as well.3

Avoid giving an infant soy-based formula, as they are rapidly developing and are especially sensitive to hormones and hormone-like compounds.

3. Soy Can Cross-React with Gluten.

Soy is one of the top allergenic foods in part because it resembles gluten on a molecular level. If you have a gluten sensitivity, your body can’t distinguish between gluten and soy. Your body could react to each food with the same immune response. If you’ve given up gluten but haven’t seen a decrease in inflammation, consider that soy in your diet could be producing your symptoms.

4. Soy is a legume

Soybeans and other legumes are not easily digested. All the protein they contain is not available to be absorbed by your body.

A bean is a seed, and seeds are designed to withstand digestion in order to be “planted” by the animals who eat them. Soybeans are high in phytic acid, a digestion inhibitor that binds to certain vital minerals (specifically zinc, iron, and calcium) and prevents their absorption.4

Not only can this lead to mineral deficiencies, but undigested food particles sitting in your gut feed gut infections and irritate your gut lining. A compromised gut lining (or leaky gut) is a determining factor in the development of autoimmune disease.

5. Soy is Goitrogenic.

Soybeans contain chemical compounds called “goitrogens” that suppress the thyroid gland by inhibiting the uptake of iodine. Iodine is necessary for the synthesis of thyroid hormone. If you have an underachieve thyroid, make sure you’re getting enough iodine, and avoid soy. Too much iodine can be harmful, so it’s important to eat a diet rich in a variety of other thyroid balancing minerals, like selenium and zinc, and take a high-quality multivitamin.

Other vegetables, especially cruciferous vegetables, are also goitrogenic. The benefits of eating antioxidant-rich vegetables like cabbage, broccoli, and kale far outweigh the risks posed by the goitrogens. Soy on the other hand isn’t worth it.

Just as people who are gluten-free sometimes rely too heavily on gluten-free products, many vegetarians depend upon soy products as meat alternatives. A soy-based vegetarian diet is likely not a healthy diet, so decrease your soy consumption as much as you can and replace it with nutritious alternatives like dark leafy greens, cruciferous vegetables, and protein-rich nuts and seeds.

Whether or not you are a vegetarian or vegan, avoid relying on soy as your main protein source. Most of us eat too much soy as it is. It’s best to limit your soy intake, but if you are going to eat it, it’s important that you:

  • Buy 100% organic soy.
  • Eat soy in its whole, unprocessed form (edamame).
  • Read package labels carefully.

To determine whether or not you have a sensitivity to soy, try completely removing it from your diet for at least two weeks and then adding it back in, tracking your symptoms along the way. I’ve created an eCourse to help you through this process if you need some extra guidance.

Multivitamin bottle.

Article Sources

  1. EWG’s 2014 Shopper’s Guide To Avoiding GMO Food. Environmental Working Group. 2014.
  2. Effects of soy phytoestrogens genistein and daidzein on breast cancer growth. ML de Lemos. The Annals of pharmacotherapy vol. 35. 2001.
  3. Could Eating Too Much Soy Be Bad for You?. Lindsey Konkel. Environmental Health News. 2009.
  4. Soy protein, phytate, and iron absorption in humans. R.F. Hurrell, et al. American Journal of Clinical Nutrition. 1992.