Plant Toxins: How These Antinutrients May Be Injuring You

AVFC Plant Toxins


EDITOR’S SUMMARY: Smart nutrition includes letting go of doctrine-thinking. The decades-old ideas you’ve clung to may be applicable now, or conversely, may not be worthy of your commitment any longer. Are you open to discoveries in the field of health which may include researchers shining new light on old beliefs? In the case of eating plants and their babies (seeds), of the 435,000 unique land plant species, some are of more concern than others. Though troubling symptoms are not always apparent, listen to the cues your body gives you. Be willing to experiment, stay curious, and allow your intuition to guide you.


By Liz Quinn


Nutrition advice has become as varied as people. With the internet and YouTube, it’s easy to access enough differing advice to feel like you’re drowning. So much so … It can make you not want to eat anything at all. (Wait, that can be good for you, too!)


Surely, doctors and scientists must agree on something. How about vegetables? Good ol’ veggies. Bzzt—try again! Believe it or not, there’s a plethora of doctors who contend that plants, at least certain varieties, are not the superfoods they’ve been cracked up to be, arguing they may actually be hurting you.


The idea of plants being toxic is at first baffling because it’s been so ingrained that leafy greens, and bright, colorful produce should be the foundation of a healthy diet—a slot long-filled by grains in the USDA food pyramid—a construct often determined in part by political lobbying. Lately, you’re more likely to hear “eat the rainbow”—certainly an improvement over the advice of 6–11 servings of grain per day, but even so, some doctors take issue with specific produce this advice promotes.


What are these health practitioners’ “beef” with plants? For many, at issue are substances they refer to as “plant toxins.” Also dubbed “antinutrients” because of their potential to prevent certain nutrients from being absorbed in your human gut. They take the form of lectins, oxalates, phytates, glucosinolates, goitrogens, and saponins, to name a handful. 


Antinutrient food examples: Found in leafy greens, nuts, and beans, oxalates can prevent calcium from being absorbed; phytates can prevent calcium as well as iron, zinc, and magnesium absorption, and are found in whole grains, seeds, legumes, and nuts. Even the cruciferous family (broccoli, cauliflower, cabbage) isn’t safe from scrutiny. These veggies contain glucosinolates and goitrogens, substances that may interfere with iodine, and affect thyroid function. 


Often, it’s not a superficial interest in nutrition that leads one to seek out off-the-beaten-path food plans, such as the limitation or elimination of vegetables, but rather, mysterious, and/or chronic health issues that entice you, while attempting to come back into physical and mental health balance. 


AVFC dry beans

Dry beans aka "pulses," seeds of legume plants

Plants and Their Seeds: A Rough Way to Go?

Here is Ben’s story, as shared in the book “The Carnivore Code.” Ben was diagnosed at age 13 with chronic inflammatory demyelinating polyneuropathy (CIDP), a neurological disease that progressively weakened and reduced sensations in his arms and legs. He tried the conventional medicine route to no avail. In the years that followed, he gave juicing, raw veganism, paleo, and keto diets a shot before finding what worked for him. After 10 days consuming only beef, salt, and water, he was “finally able to wake up and walk down the stairs like a grown-up, instead of using both feet on each stair like a toddler (because of the pain).”


At 71 years old, Melinda came to a limited-plant diet via Dr. Steven Gundry. She was diabetic, and had large squamous cell cancers on both legs—so large that chemotherapy would be ineffective, and surgery not an option. Within 6 months of reducing the antinutrients found in many plants, Melinda’s diabetes disappeared, and her cancers resolved.


If you suffer from migraines, you know the frustrating and sometimes mysterious nature of this miserable affliction. At 51, Jane, a nurse, had tried a plethora of treatments without success. She came to a limited-plant diet via Dr. Gundry, who previously suffered migraines, himself. In a matter of days, her migraines abated.


Gundry, cardiothoracic surgeon and author of “The Plant Paradox,” has focused his dietary criticism on lectins, perhaps the most-discussed of the plant toxins. He argues that plant toxins like lectins not only prevent nutrient absorption, but actually damage your digestive tract, causing “leaky gut syndrome,” and leading to autoimmune disorders. 


Leaky-gut syndrome certainly sounds troubling, but what does it mean? A single layer of cells in your intestine is tasked with bringing in good bacteria and keeping the bad out. Lectins have been shown to damage this lining, allowing various particles, including toxins and bacteria to leak through your gut into your bloodstream, hence the term “leaky gut.” This condition can contribute to the development of celiac disease, Crohn's disease, and irritable bowel syndrome, among others.


While arguably the most vocal, Gundry isn’t a lone wolf sounding the plant toxin alarm. Dr. Paul Saladino, a functional medicine M.D., and author of “The Carnivore Code,” discusses lectins extensively. (Take a moment to enjoy the fact that “salad” is part of his name.) Saladino goes into detail about the thin lining that divides (and protects) your gut from the rest of your body. 


Different types of cells within the lining of the gut connect to one another and have a crucial job: “they selectively allow certain molecules to pass between them and into the immune-cell-containing lamina propria” (a layer deeper within the intestinal wall, just beyond the gut lining). 


When lectins are ingested (in foods such as legumes, nuts, grains, and nightshades like cucumbers, tomatoes, and peppers), they can react with the thin epithelial lining of the gut. Sometimes this happens by way of causing the body to think it’s under attack, triggering crucial “tight junctions” of the protective lining to open so that immune cells can move into the gut to fight off what it perceives is an invader. Other times lectins bind directly to the “goblet cells” responsible for maintaining a healthy mucus layer in the intestine, and interfere with their function. 


AVFC plant toxins


A study published in the “Journal of Immunology” in 2020 found that plant lectins can trigger an intracellular sensor whose job is to activate a particular inflammasome (NLRP3), which mounts an inflammatory cytokine response. In simpler terms, from “Plant Lectins: Bioactivities and Bioapplications”:


“... plant lectins can act as a ‘danger signal’ . . . and might promote inflammatory diseases . . . including inflammatory bowel disease, diabetes, rheumatoid arthritis, and celiac disease.”


Researchers studying the reactivity of lectins found the four most reactive types were wheat germ agglutinin (WGA), phytohemagglutinin (PHA), soybean agglutinin, and peanut agglutinin, in that order. WGA is similar to, but not the same as gluten, the well-known controversial protein in so many foods. PHA is found in beans, namely red kidney beans, and can be harmful enough to kill you if consumed uncooked or undercooked


The scientists here believe the reactions may be due to molecular mimicry—when a foreign protein you ingest resembles a healthy, harmless protein that makes up your own body. This misidentification can cause your body to launch an attack against itself, thinking it’s fighting an invader, possibly triggering autoimmune issues. 


Just how much to avoid lectins remains controversial. Gundry goes so far as to recommend white rice and white bread if you absolutely can’t give up such grains, asserting that the hull is the lectin-laden part of the grain, and that traditional cultures who rely on such foods have known this for ages, which is why they remove the hulls and eat the white rice that remains.


However, other well-known doctors have expressed disagreement and even hostility toward Dr. Gundry, and those like him who encourage eating “white” grains, and discourage eating certain (or many) plants. 


Dr. Joel Fuhrman, a family physician, has written books, articles, and been on every talk show imaginable touting his point of view, and his nutrient-dense diet he’s dubbed “nutritarian.” He firmly disagrees with the idea that produce like peppers and tomatoes are harmful, and believes any concerns about lectins are far outweighed by the nutrients they provide. He’s also a big proponent of beans—so much so that it holds the second spot in the acronym he created for his most-recommended foods: GBOMBS (greens, beans, onions, mushrooms, berries, seeds).


Also in the pro-plant food camp is Dan Buettner, journalist and author of the best-selling book, “The Blue Zones,” which explores the “secrets” to the most long-lived places in the world. While his book is based on more than just nutrition—social connection, physical activity, and purpose are among the traits of most centenarian “zones”—many of these populations rely on, or at least incorporate beans in their diets. 


Saladino counters this, stating “The Blue Zones” data was cherry-picked. He asserts that there are other areas in the world with comparably lengthy lifespans where their diets are not plant-based. He also contends that when you take a finer look at the cultures in Buettner’s book, details are left out. Saladino offers several claims: Okinawans eat more meat than in other parts of Japan; Sardinia offers feasts of Sarda pig, and in the Nicoyan region of Costa Rica, they eat more meat, and use more animal fat to cook with than their fellow Costa Ricans, whom they outlive. So, perhaps it’s not as simple as those legumes after all. 


Granted, it can be hard to know who to trust with your dietary decisions. Gundry, Fuhrman, and Saladino all have their own books, programs, and nutritional supplements, supporting their income, and intended right livelihood. If you’re up for scouring every referential study in each of their books, and deciding whose science is most sound, go for it! If, however, you have a life to live, there’s always the principle of moderation. 


The study of lectins and “antinutrients'' is relatively new, so until more human clinical trials are done, your best bet may be to examine how you react to what you eat, particularly in the plant kingdom, and decide what makes the most sense for you. After all, health care is always better individualized, as there is no one-size-fits-all in nutrition. You can find people who thrived once they stopped eating meat, just as you can find people who, bizarre as it may sound, started filling their diets mainly with meat, and saw their health troubles fade away. Every body is different.


AVFC pressure cooker

Using a pressure cooker to remove lectins and other toxins

The Plant’s Point of View

Plants, like most living things, want to survive and propagate. You could make the argument that plants don’t want to be eaten, and thus produce lectins to protect their precious seeds. If an animal gets sick eating a certain plant, they are less likely to return to that plant for more. Lacking claws and mobility, plants are otherwise defenseless against anything that wants to eat them, so it’s a pretty ingenious move.


On the other hand, you could argue that animals (including humans) eating plants’ seeds are exactly what the plants need. When an animal eats a seeded fruit, for example, if the seed is designed with a protective coating, or component-like lectin that allows it to survive the animal’s digestion, it’s then pooped out, onto the ground, where it’s literally in fertilizer, all set to grow. 


Whether you believe so-called edible plants are your friend or foe, if you want to continue eating them, there are ways to decrease the amount of lectins in your food. You can soak, sprout, or ferment legumes, seeds, and some grains, but almost all lectin-rich foods require cooking to substantially lower their levels. 


In the acclaimed book, “Nourishing Traditions: The Cookbook that Challenges Politically Correct Nutrition and Diet Dictocrats,” author Sally Fallon offers recipes for soaking, then roasting various nuts to reduce not only their lectins, but their phytic acid content. 


Thorough cooking is especially important with beans because of their high lectin content, and highly reactive PHA protein. Using a pressure cooker is quick, easy, and effective. Because liquid helps activate the release of lectins, be sure to boil beans if you can’t use a pressure cooker. 


If you buy canned beans, rinse them before tossing them into your meal, as lectins may be lurking in the liquid. According to TastingTable, beans are blanched, canned, sealed, and then pressure cooked. Because they are cooked in the can, you’d be wise to seek out BPA-free cans, as heat releases dangerous BPAs (bisphenol A).


When it comes to nightshades, the lectins are mostly in the skin and seeds, so peeling and seeding items such as tomatoes and cucumbers will remove the majority of lectins. You can go further by pressure cooking these fruits (they are, indeed, fruits), and seeing as Fuhrman is a big proponent of tomatoes for their heart-healthy lycopene, this should please you if you’re in his camp, since cooking tomatoes increases their lycopene content.


Lastly, if you are a meat-eater, consume grass-fed/finished, and pasture-raised as much as possible. “You are what you eat,” and just as significant—you are what you eat … ate. According to Gundry, if the cows or chickens ate grains, you’ll end up ingesting those residual grain proteins. 


If you struggle with digestive issues, consider decreasing high-lectin foods for a stretch, and see how you feel. If you experience celiac or Crohn's disease, experimenting with a strict lectin and antinutrient-elimination diet could prove valuable. 


If you do have health issues, consult with your holistic medical practitioner to help with dietary decisions before making a big change. If you seem to handle fruits and veggies just fine, but want to lower your plant toxin consumption for prevention, play around with the lectin-reducing methods. You might be pleasantly surprised.




Published on September 14, 2023.


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