Are We Wrong About What Makes Food Healthy?

Some of the foods we think are the healthiest may play a role in leaky gut, autoimmune disorders, and other diseases, says goop contributor, Steven Gundry, M.D., whose research may change the way we all think about “healthy” food in the future. Gundry, who focuses on autoimmunity and microbiome disorders, sees lectins—proteins found in some plants, designed to protect them from predators—as the root cause of many diseases. As Gundry explains, lectins are like a smart bomb to the body; they can have toxic or inflammatory effects that underlie gut-related health issues like leaky gut, autoimmunity, and weight gain. His forthcoming book on the topic, The Plant Paradox, is a fascinating exploration of the evolution of plants and animals, and our relationship to the food we eat today, along with useful practical tips, eating plans, and health-boosting recipes. If you’re like us, Gundry’s insight into the modern diet, particularly concerning which plants are healthy and not, will surprise you:

A Q&A with Dr. Steven Gundry


What’s the plant paradox?


The plant paradox is actually quite simple. Everyone knows, or thinks they know, that eating a plant-based diet is good for them. From a plant’s standpoint, that’s not always the case: Plants were here first and up until animals arrived tens of millions of years later, plants had it really good. Nobody wanted to eat them! But when animals arrived, plants had a problem. They couldn’t run, hide, or fight. But they were‚ and are, chemists of amazing ability. So they resorted to chemical warfare against their new predators to make their predators sick, or to keep them from thriving, if the animal ate the plant or its babies (the seeds). When the plants’ chemical defenses worked, the smart predator went off and ate something else.

“Therein lies the paradox.
Which plants wish us harm and which wish us well?

Predators themselves evolved protective tactics, too, and for most of history there has been a sort of Cold War détente between plants and animals. Plants have evolved for their seeds, particularly in fruits, to be eaten by animals, survive digestion, and then be pooped out elsewhere with a generous dollop of fertilizer. Bacteria in animals’ intestines have evolved to enjoy some of these plant toxins (like gluten, for instance) and detoxify them. Lastly, we know that many plant compounds, referred to as polyphenols, interact directly with the immune system, brain, nerves, and blood vessels of animals and humans, improving the function of these systems.

Therein lies the paradox. Which plants wish us harm and which wish us well? Unfortunately, they don’t carry signs. But research has uncovered a roadmap to guide our choices.


What are lectins, what’s their purpose for plants, and how does it affect us?


One of the most effective plant deterrents to animal predation is the use of proteins called lectins. (Not to be confused with leptin, the hunger hormone, or lecithin, an emollient). Lectins are sometimes called sticky proteins, because they seek out particular sugar molecules on cells in our blood, the lining of our gut, and on our nerves. When the lectins attach, they essentially hack the communication system between cells and our immune systems, and literally pry open the spaces between the cells that line our intestines, producing what is now commonly known as leaky gut, which can lead to a host of unpleasant symptoms and autoimmune issues. When animals eat plant lectins, the animal is effectively experiencing an incoming guided missile attack. (Lectins can actually paralyze some insects.)

“Plants are sentient beings. They think (!), not in the way we do, but they are subject to the same evolutionary pressures to grow and have babies (seeds), and protect their babies just like animals.”

As my research has continued, I’ve become convinced that plant lectins and the havoc they promote are the root causes of almost all diseases. I say that as a tribute to what plants have done in four hundred million years on this planet. Plants are sentient beings [more on this in Dr. Gundry’s book]: They think (!), not in the way we do, but they are subject to the same evolutionary pressures to grow and have babies (seeds), and protect their babies just like animals. Plants use lectins and similar compounds to “get what they want” from animals. They trick animals to do their bidding, and they punish animals who eat them at inappropriate times. If an animal feels pain, or just not great, gets diarrhea, has heartburn, IBS, brain fog, joint pain, arthritis, and so on…the plant figures a smart animal would get the idea pretty quickly and stop eating that plant. This worked great for millions of years—until humans arrived.


If our ancestors have been eating lectin-containing foods for thousands of years, how is this a new issue?


We evolved from tree-dwelling great apes. As such, our lineage has been eating the leaves of trees and the fruit of those trees for about forty million years. The modern human didn’t appear until approximately 100,000 years ago. At that time, our diet consisted of leaves, fruits, nuts, tubers, and some fish and shellfish. So we evolved getting used to the lectins that we continually ate, and we evolved bacteria in our guts to help us handle these lectins.

“Until that time, humans stood 6 feet tall and had brains 15 percent larger than they are today!”

But we did not evolve from grass- or bean-eating animals like horses, cows, antelopes, etc. Grasses and beans have an entirely different set of lectins, which the grazing animals have evolved to tolerate, but that are (relatively) new to humans. It was only about ten thousand years ago that we began interacting with these new lectins via agriculture. The effect on humans was dramatic. Until that time, humans stood 6 feet tall and had brains 15 percent larger than they are today! In just two thousand years after the birth of agriculture, humans had shrunk to 4′ 10″! Think about it from a plant’s standpoint: A smaller predator eats less.

As I explain in the book, Seven Deadly Disruptors in our modern food and personal care products have tipped the balance of power from our previous détente to the current, out-of-control situation. In addition, broad-spectrum antibiotics, antacids, sunscreens, Advil, Aleve, and other NSAIDS, to name a few, have further disrupted our microbiome—which affects the way we and plant lectins interact with each other.


What plants do you recommend people avoid?


The longer that we have interacted with and eaten certain species of plants, the more likely we are to have developed a tolerance for those lectins. The shorter the amount of time we’ve been consuming them, the more problematic.

In general, eat less of:

  • GRAINS: We didn’t eat grains until ten thousand years ago. Our ancestors used grains and beans to selectively store more calories as fat. In a time when food was scarce, any food that promoted fat storage was a dietary winner. Now, it’s a dietary disaster.

  • BEANS: Beans have the highest lectin content of any food. The CDC reports that 20 percent of all food poisoning is caused by the lectins in undercooked beans.

  • NIGHTSHADES (potatoes, tomatoes, peppers, goji berries, and eggplant): These are American plants that have been shown to increase pain and promote autoimmune diseases and asthma. The peels and the seeds of these plants contain the lectins. Italians have traditionally peeled and deseeded tomatoes before making sauce; Southwest American Indians traditionally char, peel, and deseed their peppers.

  • SQUASHES: The squash family, like zucchini and pumpkins, are American fruits and have lectins in the seeds and peels. Also, remember that any “vegetable” with seeds is actually a fruit. [More below.]

In general, steer clear of:

  • AMERICAN GRAINS, like corn and quinoa: These are a problem for most people, in part because no European, African, or Asian population was exposed to plants from the Americas until about five hundred years ago.

  • OUT-OF-SEASON FRUIT: Until 747’s could bring blueberries to Costco from Chile in February, we had never eaten fruit year-round; It’s one of the biggest modern health hazards. It always surprises my patients to learn that Great Apes only gain weight during fruit season. Why? Because eating fruit promotes fat storage. My research, along with the research of others, has shown that year-round fruit consumption is associated with kidney damage and diabetes, among other diseases.


What are other sources of lectin in the diet?


Two thousand years ago, Northern European cows suffered a genetic mutation and began producing a lectin-like protein in their milk called Casein A1 (the normal cow makes Casein A2, a safe protein). Unfortunately, Casein A1 cows are heartier and give more milk, so most cows in the world (except those in Southern Europe), produce milk that’s harmful to humans. I’ve found that most people who react negatively to milk, get mucous from drinking milk, or think that they are lactose intolerant, in fact are affected by the lectin-like protein Casein A1, but tolerate Casein A2 from sheep, goats, buffaloes, and French, Italian, and Swiss milk products and cheeses.


Do any cooking methods solve the lectin problem?


Many people (including me) believe it was the advent of fire and cooking that finally created the modern human; for the first time, we could break down the cell walls of plants without the aid of bacteria, which resulted in our ability to use plant sources that were totally inedible like tubers, beans, and grains.

The cooking method today that is best for destroying plant lectins is the pressure cooker, which I highly recommend people use for foods like beans, tomatoes, potatoes, and grains. However, a word of caution; pressure cooking cannot destroy the lectins in wheat, oats, rye, barley, or spelt.


Which plants should we be eating more of?


We’ve been eating leaves, shoots, and flowers for millions of years. We’ve been eating cooked tubers (e.g., sweet potatoes, taro root, cassava, yucca) for hundreds of thousands of years. We’ve been eating seasonal fruit (and fruit only in season) for millions of years.

Good plants to add to the diet include:

  • LEAFY GREENS: lettuces, spinach, seaweed, etc.

  • FLOWERS AND CRUCIFEROUS VEGETABLES: broccoli, cauliflower, arugula, artichokes

  • MISCELLANEOUS VEGGIES: celery, onion, asparagus, garlic, okra, radicchio, endive





Are lectins an issue for everyone, or can some people digest them more easily?


Lectins affect everyone, but some people react more vigorously to them; I call this subset the canaries. Coal miners used to carry canaries in cages into mines because the miners couldn’t smell the toxic gases that could accumulate, but if the canaries stopped singing and flitting around, the miners ran! Lectin canaries, as detailed in The Plant Paradox, are so sensitive to lectins that a bite of a lectin-containing food can incite an autoimmune disease, or flair asthma, arthritis, migraines, IBS, MS—you name it, I’ve seen it. As I tell my canary patients, it’s both a curse and a benefit, because they will react to the bad effects of lectins long before their effects might be felt by “normal” people many years later. Having said that, if our gut’s defensive system is intact, our gut microbiome is filled with good bugs (I call them gut buddies) that eat lectins, and our gut wall fortified by the effects of vitamin D, then many of us can tolerate a vast array of lectins without much harm.


Why do you think some plants evolved to be harmful to us, but not others?


There’s the plant paradox again. Plants can harm us when they want to be left alone, but can tempt us and use us when we help them disperse their seeds or dispatch other predators. In a perverse way, think who is actually in control: Do corn and wheat plants serve the farmer or is the farmer providing food and care to the plant? It’s kind of like humans and our pets. Next time you feed your dog or pick up their poop, ask yourself who is the master and who is the servant. This complicated dance between plants and animals has been going on for hundreds of millions of years; they use us and we use them. Many of the compounds in plants are essential for our immune system, microbiome, brain, and longevity.


Anything else that surprises your patients diet-wise?


Many plants put the lectins in the hulls, the peels, and the seeds of their fruits or grains, so that shockingly, white rice, white bread, white pasta, peeled and deseeded tomatoes, peppers, and the like are safer than their whole grain or whole fruit counterparts. Why do you think that four billion people who eat rice as their staple eat white rice and not brown rice? They’ve been taking the dangerous hull off the rice for eight thousand years! (But let me be clear; these are not “free foods.” A piece of bread can raise blood sugar as much as four teaspoons of straight sugar.)


How did you come to focus on lectins?


I have been fascinated by lectins since writing my Yale undergraduate thesis on human evolutionary biology, which explored manipulating the food and environment of great apes to make a human being. But, it was reading Michael Pollan’s 2001 book, The Botany of Desire, that rekindled my interest in the power of plants as chemists and alchemists to manipulate animal behavior.

Dr. Gundry is the director of the International Heart & Lung Institute in Palm Springs, California, and the founder/director of the Center for Restorative Medicine in Palm Springs and Santa Barbara. He is the author of Dr. Gundry’s Diet Evolution: Turn Off the Genes That Are Killing You and Your Waistline and Drop the Weight for Good and the forthcoming The Plant Paradox: The Hidden Dangers in “Healthy” Foods That Cause Disease and Weight Gain.

The views expressed in this article intend to highlight alternative studies and induce conversation. They are the views of the author and do not necessarily represent the views of goop, and are for informational purposes only, even if and to the extent that this article features the advice of physicians and medical practitioners. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment, and should never be relied upon for specific medical advice.

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