Let’s be real: soy is kind of a controversial food. Once it was considered to be the ultimate health food, and then suddenly it became the worst substance you could be eating. What gives? What do we actually know about soy, and is it a right fit for you? With all food, context matters, and it’s usually not a simple case of bad or good. So let’s dive in.
Soybeans are a type of legume, and they’ve been a staple of traditional Asian diets for thousands of years. They can be whole, or they can be processed (and you can bet that has an effect on their health properties). Some soy foods include:
Textured vegetable protein
Soy protein powder
The biggest controversy when it comes to soy is its potential risk in impairing thyroid function and causing cancer (particularly breast cancer). This is because soy contains isoflavones, which are compounds that mimic estrogen. Early research on these compounds found that they could promote the growth of cancer cells, cause infertility and negatively impact thyroid function. (1, 2, 3) But again, context is key: most of the research that found these links looked at isolated soy compounds, removed from its whole food source. The problem with this is that we don’t typically eat soy like that, and whole foods behave differently in the body in comparison to isolated compounds because they work synergistically with other nutrients and fibre.Another thing to note is that these studies looked at the effects of soy either in animals or in vitro (test tubes), and typically in larger quantities than we’d ever eat in a day. While this might give us some insight, it doesn’t account for the fact that soy may act differently in the human body or that some animals aren’t designed to tolerate soy. In fact, research in humans found that soy could actually help fertility. (4) Recent research shows that soy products can also help to reduce the risk of breast cancer unless you’re a carrier for the BRCA2 mutation gene, in which case you might want to limit or avoid soy. (5)
Another common reason to avoid soy is because it contains antinutrients like phytates, agglutinins and trypsin inhibitors. Animal research done on agglutinins in soy found that it could increase intestinal permeability and disrupt healthy gut bacteria. (6,7)However, like other foods that contain antinutrients, cooking, fermenting and sprouting soy helps to decrease the levels of antinutrients and also increase digestibility. (8) Again, how soy affects you will largely depend on the state of your own gut health.
One of the best ways to consume soy is in the form of tempeh, as it’s a fermented, whole-food source of protein.
It Contains Prebiotics. Tempeh is a rich source of prebiotics—the healthy fibre that feeds gut bacteria. (10) Research suggests that prebiotics can not only improve gut health, but they can also help to reduce inflammation. (11, 12)
It Contains Antioxidants. Research shows that soy isoflavones contain antioxidant properties that help to reduce oxidative stress, and that tempeh contains more antioxidants compared to whole soybeans. (13, 14)
It’s High In Protein + Fibre To Keep You Full. Tempeh is a great source of plant-based protein, whether you follow a vegan or omnivorous diet. One 4-oz serving of tempeh contains 20g of protein—with 7g of fibre! Protein helps to satiate hunger, and research shows that it doesn’t matter whether or not it comes from a plant-based or animal-based source to see the benefit. (13)
If you’re looking for a source of plant-based protein, soy in its whole food form might be a healthy option for you in moderation. You may want to limit soy if you have an underlying health condition (like hypothyroidism), but if you’re in good health, 3-5 servings of soy a week is perfectly healthy!Ready to give it a try? Impact Kitchen is super excited to launch our new organic, non-GMO marinated tempeh, available at all locations. We’ve had so many requests over the years for another plant-based option, and we didn’t want you to go unheard! We’ve also been interested in the effect of a plant-based diet on longevity and have been looking to places—like the Blue Zones of Italy, Greece and Japan—to see what they’re doing. And as it turns out, these populations are eating a primarily plant-based diet with the inclusion of soy and legumes. (14,15) You’ll notice we’ve even added some new bowls to our menu (the Victory and the Thrive bowls!) that include legumes and lots of plants for this very reason!Let us know: what are your thoughts on soy? Have your views shifted over the views with new research?
The information provided on Impact Everyday is not a substitute for professional medical advice or treatment for specific medical conditions. You should not use this information to diagnose or treat a health problem without doing your own researching and working with a medical expert. By reading this website, you acknowledge that you are responsible for your own health decisions, and Impact Everyday is not liable for how the information on this website is used.The information on this site is for informational purposes only, and is not meant to be a substitute for professional medical advice. If you have a medical concern or condition, please contact your healthcare professional.