In our fast-paced world, maintaining a healthy and balanced diet with ingredients you recognize can feel like a monumental challenge. Even health and wellness professionals struggle to navigate supermarket aisles filled with products featuring new and functional ingredients. One enhanced ingredient commonly found in plant-based protein bars, cereals, and veggie burgers is soy protein isolate. But what is soy protein isolate and should you eat it?
What is Soy Protein Isolate?
Soy is derived from soybeans and contains fat and carbohydrates (mostly made up of fiber, naturally occurring sugar, and protein). Soy protein isolate (SPI) is a protein that has been isolated from soybeans via chemical engineering.
So how does the marvel of modern science achieve this? First, soybeans are washed with acid and neutralized in an alkaline (or, basic) solution. At the end of the SPI process, you’re left with a dry powder that’s about 85-90% protein and nearly carbohydrate and fat-free. This SPI powder is then included in protein powders, bars, and even plant-based burgers.
Sounds great, right—a protein powerhouse with a great nutritional value per serving? Or too good to be true? That entire chemical process used to create SPI also strips the soy protein of fiber, zinc, calcium, magnesium, and iron that you would normally ingest if you ate the whole soybean. And, there’s more…
Does Soy Protein Isolate Contain Unhealthy Additives?
The chemical process required to isolate the protein often leaves behind substances like aluminum and hexane. Those metals, while not harmful in small amounts, can become toxic as they accumulate in your body and should be limited in your diets as much as possible.
Further, after the stripping process, SPI is dried using a spray-drying method that can form nitrites, compounds that have been known to form carcinogens in the body.
So, Should You Eat Soy Protein Isolate?
Most health and wellness professionals will tell you to ditch processed foods, including SPI. Soy Protein Isolate is a highly processed product and has increased levels of trypsin inhibitors—chemicals that reduce available trypsin, an enzyme found in the small intestine that helps aid with the digestion of protein in the body. Therefore, consuming SPI may cause stomach issues, nausea, and intestinal discomfort for some—in addition to the reasons to avoid SPI listed above.
Considerations for Vegans and Vegetarians
If you’re looking to up your daily non-animal protein, go to the whole-food source. The key is to diversify your protein sources to maximize nutrient variability in your diet.
There are many healthy high-quality plant-based protein options for your diet. Here’s a few:
These options are also rich in fiber, vitamins, and minerals. If you want to go the soy route, stick to natural sources like edamame and tofu. Fermented soy options, like miso, tempeh, and natto, are even more preferable because they are easier to digest and provide great probiotic benefits that reduce the natural estrogen content in soy foods.
When striving to lead your most nutritious life, go back to the basics—eat whole unprocessed foods. Try to avoid as many things that come in powder form, or from a box, bag, or plastic container as possible. Your body will thank you for it!
The Nutritious Life Editors are a team of healthy lifestyle enthusiasts who not only subscribe to — and live! — the 8 Pillars of a Nutritious Life, but also have access to some of the savviest thought leaders in the health and wellness space — including our founder and resident dietitian, Keri Glassman. From the hottest trends in wellness to the latest medical science, we stay on top of it all in order to deliver the info YOU need to live your most nutritious life.
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