What’s the Truth About Soy?

Last Updated on May 28, 2023 by Heather Reseck

Soybeans are nutrient-dense legumes that have been consumed by humans for hundreds of years. Soybeans are a good source of protein, fiber, healthy fats, and minerals. Soy foods have recently gained popularity in the Western world due to their versatility. 

Yet, soy is a controversial topic in the field of nutrition. Concerns raised by meat-promoting organizations have caused soy phobia. What is the truth?

Last year Frontiers in Nutrition published a scientific review article called “The Health Effects Of Soy: A Reference Guide For Health Professionals.” Two of the authors are a husband-wife team who used to live in Port Townsend, Washington: Mark Messina, Ph.D. a soy foods expert, and his wife Virginia Messina, a plant-based registered dietitian and author. I had the opportunity to meet them and have a lot of respect for their research. Refer to their article for more information.

Seven Myths About Soy

There are myths about soy foods that are not supported by scientific evidence. Here are a few of the most common:

Myth #1: Soy has to be fermented to be digestible. 

The two most common fermented soy foods are tempeh and miso. Some people find them easier to digest.  (Soy sauce is not included because it is a condiment, not a food). Globally, most soy is consumed in the unfermented form: tofu and soy milk. Both are easy to digest.  Some people express concerns about lectins. Dr. Michael Greger explains that bad lectins are destroyed by cooking. The benefits of lectins may explain why those who eat more beans have less cancer.

Myth #2: Soy foods contain estrogen.

Soy foods do contain compounds called phytoestrogens, which can act as a weak form of estrogen in the body. However, the amount of phytoestrogens in soy foods is much lower than the amount of estrogen produced by the body. In fact, some studies have found that consuming soy foods may help to balance hormones and reduce symptoms of menopause.

Myth #3: All soy foods are genetically modified.

While it is true that the majority of soy grown in the US is genetically modified, there are many non-GMO soy products available. Look for products that are certified organic and/or non-GMO verified.

Myth #4: Soy is a very common allergen.

Soy is one of the nine allergenic foods that must be declared on product labels in the U.S. The others are milk/dairy, eggs, fish, crustacean shellfish, tree nuts, peanuts, sesame, and wheat. The prevalence of soy allergy is relatively low in comparison to the other eight foods. Soy allergy is more common in children and they often outgrow it by age 10. 

Myth #5: Soy foods are endocrine disruptors.

This myth is based on animal studies. Guess what?  Rats metabolize soy differently than humans! Soybeans are a rich source of isoflavones, which are classified as phytoestrogens. However, there is ample human data regarding the health effects of isoflavones. The available evidence indicates that isoflavone intake does not adversely affect thyroid function. Adverse effects are also not seen on breast or endometrial tissue or estrogen levels in women, or male reproductive hormones. 

Myth #6: Women with breast cancer should avoid soy.

The American Cancer Society, the American Institute for Cancer Research, the World Cancer Research Fund International, and the Canadian Cancer Society all concluded that women diagnosed with breast cancer can safely consume soy.

Myth #7: Processed soy foods are worse than meat.

Dr. Michael Greger dispelled this myth in a video comparing Beyond Burgers and Impossible Burgers to hamburgers. Highly processed plant protein is better than animal protein. However, simply prepared homemade burgers are still better than ultra-processed ones. 

Hexane in Processed Soy

There are some legitimate concerns about processed soy, which includes soy protein isolate, soy protein concentrate, textured vegetable protein, soybean oil, soy lecithin, and soy flour. Soybeans are bathed in a solvent called hexane to separate the soybean oil from protein. Hexane is a byproduct of gasoline refining. It is a neurotoxin and a hazardous air pollutant. 

Steps to Avoid Hexane in Soy

Here are some steps you can take to avoid hexane-processed soy products:

1. Look for certified organic soy products: Organic certification standards prohibit the use of hexane in processing. Look for products that are certified organic by a recognized certification agency. 
2. Choose non-GMO products: Many non-GMO soy products are also processed using natural methods that do not involve hexane. Look for non-GMO verified products or those that indicate hexane-free on the label. 
3. Choose minimally processed soy foods:  Organic tofu, tempeh, and edamame (green soybeans) are some of the best ways to consume soy. Other options include roasted soy nuts, cooked soybeans, soy milk, miso, and Butler Soy Curls (affiliate link).  
4. Avoid the following ingredients unless the package specifically makes an organic or non-hexane claim.  

• Soy protein
• Soy protein isolate
• Soy protein concentrate
• Textured vegetable protein
• Soy lecithin 
• Soy flour
• Soybean or vegetable oil

5. Read ingredient labels carefully. Clif Bar is an example of a major national brand that uses some organic ingredients and yet uses hexane-extracted soy protein. A few natural companies go out of their way to source non-hexane-extracted soy ingredients. Also, note that most conventional seed and vegetable oils are extracted with hexane. See the chart below.

Healthier Hexane-Free Swaps

Instead of this:	Choose this:
Textured vegetable protein	Butler Soy Curls (affiliate link)
Soy lecithin	Sunflower lecithin
Shelf-stable firm and extra-firm tofu made with soy protein isolate	Shelf-stable soft or organic tofu made without soy protein isolate
Soy flour	Organic soy flour. Chickpea flour.
Veggie burgers made with soy protein concentrate	Homemade veggie burgers. Veggie burgers made without hexane and highly processed ingredients.
Soybean oil, vegetable, avocado, canola, sunflower, safflower, corn, cottonseed, peanut, sesame, palm kernel, palm, and refined olive oils	Expeller-pressed extra-virgin olive oil. Organic expeller-pressed hexane-free oils.

Organic, non-GMO, hexane-free soy is a healthy versatile food that can be enjoyed in a variety of dishes.

Recipe to Try

Vegan Chicken Salad: a vegan sandwich spread, made with Soy Curls and jackfruit, that makes a delicious sandwich filling for picnics and packed lunches.