The Hidden Dangers of Processed Plant Proteins

Sara Keough MS, CNS, LDN- Integrative Eco-Nutritionist
Understanding Ag, LLC Technical Advisor

While animal products have been routinely vilified and branded as promoting heart disease, cancer, and other chronic diseases, it turns out there is no solid evidence to support these claims. Yet, mainstream restaurants and supermarkets continue to make room for alternative meat items on their menus and shelves based largely on the perception that they’re healthier alternatives to meat. But these highly processed, plant-based meats come with real dangers that belie their “healthier” billing.

In Part 2 of this “Artificial Animals” series, we’ll sort fact from fiction and creative marketing from solid science, to challenge the assertion that “plant-based meats are a healthy alternative.”

Nutrients and Ingredients in Perspective

Through persistent advertising and misinformation from popular books and documentaries, the term “plant-based” has led many consumers to believe such products promote better health. In surveys evaluating consumer interest in plant-based meats, improving one’s health is often ranked as the biggest motivator in wanting to sample these products. In one evaluation, participants considered a plant-based burger to be healthier than a beef burger when asked to compare only nutrition fact labels. Interestingly, many reported that the nutrition facts were more influential in their decision than the actual ingredients themselves.

However, evaluating the healthfulness of a product based primarily on its caloric and macronutrient content completely disregards the importance we should be placing on the specific food items, additives, or chemicals contained within that product.

Pictured here are ingredient labels for two top-selling brands of plant-based meat burgers. Upon close inspection, one could probably spot several questionable ingredients on each label. Soy or pea protein might raise a red flag for those concerned with food allergies, digestive issues, or autoimmune diseases. Oxidized plant oils high in inflammatory polyunsaturated fats, such as sunflower oil and canola oil, might also stand out. Additives like methylcellulose, yeast extract, modified food starch, natural flavors, cultured dextrose, and refined coconut oil are commonly found in ultra-processed foods and derived from industrial or laboratory manipulation. Novel ingredients that were never historically consumed by humans, such as genetically engineered soy leghemoglobin, lack adequate safety studies and could also pose potential new health risks for consumers.

Mind your Peas and Soy

Soy, often found in many meat alternatives, is frequently touted for its high protein, fiber, and mineral content. Yet, over eighty years of research has shown that soy can produce many harmful health effects. Many of these concerns are due to the vast number of “anti- nutrients” found within soy, the plant compounds that can lead to an array of health issues such as digestive disorders, hormone imbalances, or immunologic reactions. Anti-nutrients are also found in other legumes, grains, nuts, seeds, and certain vegetables. For most people, consuming small quantities of anti-nutrients found in whole, unprocessed foods may not present a major health concern. Certain preparation methods, such as fermentation, sprouting, soaking, and pressure cooking, can help remove some anti-nutrients or lessen their impact. Yet, those with digestive issues or immune system disorders are often highly sensitive to even small amounts of anti-nutrients.

The soy protein primarily used in most plant-based meats is heavily processed and stripped from its natural, whole food form. Furthermore, the heat processing of soy does not always breakdown down certain anti-nutrients, such as lectins. Additional anti-nutrient compounds may even form during the heating and hexane processing of soy protein isolates. Some of the primary anti-nutrients found in soy include phytoestrogens (associated with some cancers and hormonal issues), goitrogens (that can disrupt thyroid function), lectins (implicated in autoimmune disorders and intestinal permeability), phytic acid (which impedes mineral absorption), and trypsin inhibitors (that can block enzymes in the gut that aid in digestion of proteins). Studies have also shown harmful effects of many other anti-nutrient compounds in soy including saponins, oxalates, hemagglutinin, and perhaps most alarming, aquaporins. Food aquaporins are particularly concerning due to their association with neuroinflammatory and neurodegenerative diseases. These anti-nutrients resemble AQP4 proteins in the human brain, and when the immune system mounts an attack against aquaporins it may also strike tissues in the brain.

While it’s true that soy has been consumed for thousands of years in Asian cultures, it was nothing like the genetically modified soy of today. Contrary to popular belief, soy also was not a staple food in these cultures and was typically consumed as a condiment or occasional meat replacement, often in fermented forms such as miso, tempeh, natto, and soy sauce. The soy found in most popular brands of artificial animal products is often genetically modified and grown with many toxic pesticides. Some soy samples evaluated by the USDA Pesticide Data Program revealed 14 total toxin residues, including the herbicide glyphosate which is linked to numerous conditions such as cancer, immune dysfunction, and disruption of the human microbiome.

Pea protein has become increasingly popular in plant-based products as consumers shy away from soy; however, these isolated plant proteins still pose similar health risks. Peas are in the legume family, like soybeans, and also contain many anti-nutrients. Soy is ranked as one of the top eight food allergens in the U.S., particularly among infants and children, and some pediatricians have raised serious concerns about the rising allergenicity of pea protein. And while most people don’t have a true allergy to soy or peas, many might instead develop a “food sensitivity” that may not produce an acute immune system reaction, but can still lead to severe and chronic health issues such as autoimmune diseases, obesity, digestive disorders, neurological conditions, skin issues, and many other common ailments.

The high heat processing and isolation of proteins from soybean and peas also presents unique problems. Isolation of proteins from their whole food form generates compounds that are not naturally occurring in the food and may trigger inflammation or immune system reactions. For example, the high heat, chemical processing of soy protein isolates has been known to produce a protein compound called lysinoalanine, which is shown in some rat studies to cause kidney and pancreatic damage. The harmful effects of this compound have not yet been extensively studied in humans. Hexane, a chemical solvent used in the industrial processing of plant oils and protein isolates, is a common contaminant in many soy products and is a known neurotoxin. Peas, similar to soybeans, may be derived from farming operations that use harsh agrochemicals. The Detox Project found some pea protein products have been contaminated with the herbicide residue, glyphosate.

It’s important to consider that consumption of peas and soy products as part of a healthy diet looks strikingly different from the processed versions found in alternative meat products. Clearly, we would only want to consume such foods that are organic, free of genetic modification and chemical contaminants, and in relatively small, infrequent portions as part of a diverse diet. This might look like a serving of peas as a side dish or a bowl of miso soup to accompany a meal. However, consuming industrially isolated proteins from chemical-laden, GMO soybeans or peas as a staple food is completely unnatural and poses many health risks.

The next article in this series will take a deep dive into the health concerns associated with other ingredients in plant-based meats, such as refined plant oils, additives, and perhaps one of the most controversial ingredients, the genetically engineered soy leghemoglobin introduced to the market in the Impossible™ Burger. 

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