- Plants use chemistry for self-defense against predators and pests. One of the plant kingdom’s self-defense systems is lectins — proteins that seek out and bind to certain sugar molecules on the surface of cells
- Some — including wheat germ agglutinin found in wheat — bind to specific receptor sites on your intestinal mucosal cells and interfere with the absorption of nutrients across your intestinal wall
- Lectins are strongly associated with autoimmune disorders of all kinds, primarily by triggering leaky gut
By Dr. Mercola
Are you eating a healthy, whole food diet yet still struggle with weight gain and health problems? Part of the problem might have to do with lectins. Dr. Steven Gundry,1 author of “The Plant Paradox: The Hidden Dangers in ‘Healthy’ Foods That Cause Disease and Weight Gain,” makes a strong case for a lectin-free diet.
While trained as a cardiothoracic surgeon, Gundry now specializes in treating patients holistically, focusing on food. He’s been director of The International Heart and Lung Institute Center for Restorative Medicine for the past 17 years. Before that, he was a clinical associate at the National Institutes of Health, where he invented devices that reverse cell death associated with acute heart attacks.
He’s also been a professor of surgery and pediatrics at the Loma Linda School of Medicine and chairman of the Department of Cardiothoracic Surgery at Loma University Medical Center. I read about 150 books per year, most of which relate to health. Many of these books I can read in less than an hour, because they’re just saying the same old thing. Gundry’s book is not one of those. It’s a great resource filled with novel information.
What Are Lectins?
From an evolutionary standpoint, any creature, including plants, has a built-in imperative to grow, thrive and propagate. Plants, being rooted into the ground, cannot outrun a predatory insect. Instead, plants use chemistry for self-defense. One of the plant kingdom’s self-defense systems is lectins — not to be confused with lecithin or leptin.
Lectins are plant proteins, sometimes called sticky proteins or glyca-binding proteins, because they seek out and bind to certain sugar molecules on the surface of cells. There are many types of lectins, and the main difference between them is the type of sugar each prefers and binds to.
Some — including wheat germ agglutinin (WGA), found in wheat and other grass-family seeds — bind to specific receptor sites on your intestinal mucosal cells and interfere with the absorption of nutrients across your intestinal wall. As such, they act as “anti-nutrients,” and can have a detrimental effect on your gut microbiome by shifting the balance of your bacterial flora — a common precursor to leaky gut.
“I like to think of it as they hack into our communication system, or any predator’s communication system,” Gundry says. “For instance, in insects, they attack a sugar called sialic acid which, among other things, sits between the endings of nerves. One nerve talks to the other nerve by acetylcholine jumping through that space.
Sialic acid allows that to happen. Lectins bind to sialic acid and so interrupt nerve transmission. If you think about it, paralyzing an insect is a great defense system because if the insect can’t move, bingo, you’ve solved the problem. One of the things I’ve learned through the years through my patients is we’re just a giant insect to a plant.
What may happen to an insect fairly instantaneously by eating some plant lectins may take years in us, who are giant insects, to manifest. It may manifest as neuropathy, it may manifest as brain fog, arthritis or heart disease. But the longer I do this, the more I’m convinced that almost every disease process … can be traced back to … plant lectins.
That’s a long-winded explanation for how plants don’t like us. They absolutely don’t want to be eaten. They’ve had 400 million years to work out defense systems — a really long time.”
The Role of Your Microbiome
One of the things that struck me about Gundry’s approach is that it targets the mitochondria and the microbiome, both of which are vital for optimal health. Few physicians, even those in the integrative medicine field, fully understand the importance of mitochondrial function, but Gundry certainly does. And, while the human genome has received a majority of the scientific attention, the bacterial microbiome genome is actually far more important. As noted by Gundry:
“Our microbiome is, I think, our early warning system, because about 99 percent of all the genes that make up [the human body] are actually nonhuman, they’re bacterial, viral and fungal … [from which] we’ve uploaded most of the information about interacting with our environment … because the microbiome is capable of almost instantaneous changing and information processing that we actually don’t have the ability to do.
We’re beginning to realize … that the microbiome is not only how we interact with plant materials … like lectins, but probably more importantly, our microbiome teaches our immune system whether a particular plant compound is a friend or foe [based on] how long we’ve known that plant compound.
There are lectins in everything. But the longer we’ve interacted with lectins and the longer our microbiome has interacted with them, the more our microbiome kind of tells our immune system, ‘Hey, guys, it’s cool. We’ve known these guys for 40 million years. Chill out. They’re a pain, but we can handle them.’
From an evolutionary perspective, if you look at modern foods — say the grains and the beans, which we started interacting with 10,000 years ago, which is a blink of time — our microbiome [regards them as] foreign substances … [T]here’s no lectin speed dating in evolution.”
The Importance of Mitochondrial Function
With regard to mitochondria, “mitochondrial flexibility is one of the unique things that make us human,” Gundry says, comparing the human race to a “fat-storing ape.” Whether you ascribe to the evolutionary theory or not, humans and apes have many genetic similarities, but the ability to store fat is a unique human feature. No other great apes can do that.
Chimps, gorillas and orangutans carry 3 percent body fat. Few humans could ever achieve that low of a body fat percentage unless we were near death from starvation.
“The reason we’re designed to [store fat is to] be able to access fat for fuel,” Gundry says. “The reason why [humans] have been able to take over all parts of the world … [is] because we can cycle back and forth, having our mitochondria use fat for fuel or glucose for fuel. We’re designed to shift very quickly … even within 24 hours.
[Most people] no longer have that metabolic flexibility [because] we’ve been constantly bombarding our mitochondria with an overload of glucose as a fuel, and that really underlies, I think, most disease processes.”
How Intermittent Fasting Boosts Mitochondrial Flexibility
One of the strategies Gundry recommends and uses to improve his own metabolic flexibility is intermittent fasting. For nearly a decade now, he’s been fasting for 22 hours a day, five days a week, from January through June 1, which means he eats all his calories for the day during a two-hour window. On the weekends, he eats lunch and dinner.
“I don’t eat breakfast. I don’t eat lunch. I eat my calories between 6 and 8 o’clock at night. I do that because my wife and I are at home at that time. If I was really smart, I would [eat] earlier in the day, but, you know, you’ve got to be practical in one way or another …
In summer, I’ll have a smoothie with some MCT oil in it, half an avocado, some romaine lettuce, spinach, half a lemon and a little bit of vanilla or stevia. Then I won’t eat lunch. At dinner, same sort of thing, I try to pack all of my calories in between 6 and 8 o’clock at night …
[June 1], I finished my winter fast, if you will. Now, why do I do that? [Historically], food was a rare thing to find [during the winter]. Again, our metabolic advantage is we’re really good at starvation. It’s what allowed us to survive.
We know that during food scarcity, not only do our mitochondria rev up, but more importantly, our entire immune system and genetic monitoring basically says, ‘Look, times are tough. We don’t know when the next good food supply is going to come. We’ve got to make it through to that next period. We’re going to look at every cell in our body. We’re going to look at whether they’re pulling their own weight.
Are they odd? Are they not very fuel-efficient? We’re going to jettison that. We’re going to create apoptosis until these cells commit suicide.’ It’s kind of like if we were in a hot air balloon and we’re heading for the mountain and we’re going to crash, we’ve got to start throwing things overboard to get more lift.
I think that’s a fundamental principle that you’ve known for a number of years and that I’ve certainly preached for a number of years. The more we understand that that’s how successful aging occurs and study successful agers, one of the things that’s fascinating, particularly in an animal model, is that this intermittent fasting, this challenging [your mitochondria], is the way to do it.”
Although I used to do 14- to 16-hour intermittent fasts, because I felt that it was wise to increase glycogen stores prior to strength training, I have come to realize that’s not true. In fact, it’s counterproductive, as carbs after strength training can increase insulin and diminish IGF-1 response and blunt the anabolic stimulus. So now I am fasting for 18 to 20 hours a day and do all my strength training in a fasted state.
That may sound challenging, but I can confidently assure you, from personal experience, that once you are fat adapted there are no cravings. Additionally, I recently interviewed Dr. Dale Bredesen, who wrote the book “The End of Alzheimer’s: The First Program to Prevent and Reverse Cognitive Decline,” in which he discusses how ApoE4 is a genetic risk factor for Alzheimer’s but ONLY if you don’t intermittent fast. If you do, it will likely actually decrease your risk for the disease as its biological function is to allow us to go for longer periods of time without food.
The Importance of Ketogenic Cycling
Gundry also understands the importance of cycling in and out of nutritional ketosis. While your body is still burning sugar as its primary fuel, you’ll want to be quite strict about not going over your net carb allotment. But once your body has regained the metabolic flexibility to burn fat, it’s really important to cycle in and out or on and off.
I suggest doubling, tripling or even quadrupling your net carbs two days a week, because the metabolic “magic” actually happens during the refeeding phase. As noted by Gundry:
“You have to look at it evolutionarily. It really was feast or famine. When we hit large amounts of food, whether it was a fruit tree or whether it was honey or a wildebeest or a mastodon, there was no food storage system. People tend to forget that nobody walked out of their cave and said, ‘What’s for breakfast?’ There was no refrigerator to have organic berries in every day.
When we chanced upon fuel, then our beautiful design [allowed us to] eat large quantities of [food] and store it as fat. Because, very shortly, whether it was a period of drought, whether it was a period of winter, we were going to regress. I’d like people to think of circadian rhythms. Obviously, we have a 24-hour clock. We have a moon clock. We have seasonal clocks.
What I like people to think of is that we have a period of every year where [we’re in] a growth cycle … That’s the time of growth and it’s a time to reproduce. Then there’s a time of involution, whether it’s a tree dropping its leaves, whether it’s an animal hibernating.
That’s the time where we kind of take stock of everything. That yin and yang, that flow that would happen every year on seasonal basis has completely been lost. We have to have periods where we consume excess calories, then we have to have periods where the exact opposite happens.
Years ago, after my first book came out, I was invited to Phoenix, Arizona, by a blogger named John Kiefer. Kiefer said you should burn fat for fuel most of the time. But every week, you should have what’s called ‘carb nite loading.’ He chanced upon this by accident, but he made a career out of it. I picked his brain and he picked my brain. I think he’s absolutely right.”
Lectins Are Strongly Associated With Autoimmune Diseases of All Kinds
Since we just talked about carb-loading at least once or twice a week (once you’ve regained the ability to burn fat for fuel), it’s worth stressing that these ought to be healthy carbohydrates, and ideally lectin-free. While intermittent fasting and eating a ketogenic (high-fat, low-carb, moderate protein) diet will dramatically reduce your risk of chronic disease, lectins may still cause trouble. One of the primary issues is autoimmune diseases.
“One of the things I talk about in the book that really made me hyper-focused on lectins was a friend of mine who was a very early adopter of my first program. I call him Tony in the book. Tony had really bad vitiligo. That’s … where the [skin] pigmentation is lost. Vitiligo is an autoimmune disease.
What happens is we attack the pigment-forming cells in our skin called melanocytes. Melanocytes are actually modified neural cells. They migrate from the neural crest to our skin in embryonic development. When Tony started my program, a few months later, he came up to visit me. He said, ‘You’re not going to believe this. My vitiligo is gone.’ I’m looking at him and I’m going, ‘Wow. That’s impressive.’
He said, ‘How did that happen?’ I could have said, ‘Well, this is a very anti-inflammatory diet. It’s high in antioxidants.’ But because I’m a researcher, I said, ‘No. That’s too simple.’ I said, ‘Melanocytes. Neural Cells. What’s the target of lectins in insects? Neural cells! Could it be that lectins are why [his body is] attacking his neural cells? What I’ve done is I’ve removed lectins from his diet.’
I lost track of him for a number of years. I was on a health panel in New York City two years ago. I saw him and he’s covered with vitiligo again. I said, ‘What happened?’ He says, ‘You know. I fell off [the diet]. I really need to get back on.’ I said, ‘This is a great experiment. Come on. Here’s the list. Go for it.’
We were just on a panel at Harvard two months ago. He’s chairing the panel. He says, ‘I’ve got to show you — everybody — the vitiligo’s gone because I took lectins back out of my diet. It sounds silly but here’s the proof.'”
One way by which lectins cause harm is through molecular mimicry. They resemble proteins in the thyroid gland, in your joint spaces and in nerves. They mimic myelin sheath proteins.
The reason why lectins will in one person cause vitiligo or psoriasis, and in another attack the thyroid or cause rheumatoid arthritis, is still unknown. What is known is that one of the underlying factors in all of these disease processes is the penetration of the gut wall by lectins and their co-travelers, lipopolysaccharides (LPSs), also known as endotoxins, which tend to elicit very strong immune responses.
“One of the things I found in all my autoimmune patients is they had profoundly low levels of vitamin D … Interestingly, when you finally seal the gut … all of a sudden, their vitamin D levels went sky high and I could back down on the dosage.
Vitamin D is essential to tell the stem cells at the bottom of the crypts in the villi to grow and divide. Without vitamin D stimulating them, they just sit there and don’t repair the gut. I think plants are so intelligent, it’s shocking. I think one of the plant strategies is that if you have low vitamin D, because you can’t absorb it, then you can’t repair your gut. You’re a horrible predator. You won’t reproduce. You won’t walk.
Vitamin D is really one of the keys to autoimmune disease. Lectins are the other key. I’ve been blessed by knowing thousands of autoimmune patients who I call ‘canaries,’ because they react almost instantaneously to lectins. It’s interesting. Everybody has their own certain lectin or lectins that they really react to.
This morning I had a woman who has rheumatoid arthritis. Her rheumatoid markers or anti-CCP3 markers have gone up. Her IL-17 had gone up. I said, ‘All right. What are you doing? What’s going on?’ She said, ‘No, no. I’m perfect. I know your list backwards and forwards.’ I said, ‘No. There’s something.'”
A Sample Case History of Crohn’s Disease
As it turns out, she’s been eating raw (unpeeled) almonds, and almond peels contain lectins. Another patient’s markers went up after going on a cashew binge, forgetting that cashews are an American bean and hence high in lectins. The answer for autoimmune patients, Gundry says, is to remove lectins from the diet and add vitamin D, which together will help “heal and seal” the gut, thereby preventing the autoimmune response.
“I mention a young woman who has Crohn’s disease in the book. Her well-meaning doctor at the Mayo Clinic told her that food had nothing to do with Crohn’s disease. She had been cured of Crohn’s disease with my program. He told her it was the placebo effect. We still laugh at that one. She ate a couple of Christmas cookies after she got off the phone with him.
Of course, it was like throwing a bomb in her stomach. She had horrible cramps and diarrhea. We skyped and she said, ‘Why don’t doctors see this?’ Like I talk about in the book, we can’t see unless our eyes are open …
I was lucky enough that when I met the guy who changed my life, Big Ed, who cleaned out his arteries with diet and supplements, [I had] my eyes open. I said, ‘This is not chance. How did [he] do this?’ Luckily, because of my evolutionary background, I was able to piece it together.”
Which Foods Have the Most Problematic Lectins?
|Potatoes||Eggplants||Tomatoes||Peppers||Goji berries||Lima beans|
|Cashews||Peanuts||Sunflower seeds||Chia seeds||Pumpkin seeds||Kidney beans|
Another common lectin is the A1 casein protein, found in most of today’s dairy cows. I’ve talked a lot about the benefits of raw milk on my site. The devil’s in the details however, and aside from being high in sugar, even raw dairy may cause problems if it has A1 casein.
“Casein A2 is the normal protein in milk, besides whey. It’s present in sheep, goats and water buffalos. But, most of the cows in the world are now casein A1 producers. They make a lectin-like protein called casein A1, which is metabolized in our gut to make beta-casomorphin, which is a very interesting thing. They can attach to the beta cell of the pancreas and incite an autoimmune attack on the pancreas.
I and others are pretty convinced that [many cases] of Type 1 juvenile diabetics is because of the casein A1 in milk. I’ve been convinced through the years that not only is it the problem, but people who think they’re lactose intolerant or that milk gives them mucus, it’s the casein A1 … Raw milk is great, as long as it came from the right cow … [Some] Jerseys are A1 and [some are] A2. Holsteins are A1.”
More and more people are now starting to recognize this, and there are even grassroots movements pushing for A2 milk in California and Ohio. Jeni’s Ice Cream gets all her milk from Snowville Creamery, which is an A2 farm. “I’ve actually talked to those people. They get it,” Gundry says. There have even been attempts to introduce A2 milk on a larger scale, but each attempt has been crushed by the American Dairy Council, for obvious reasons.
Wheat — Going Beyond Gluten
Wheat germ agglutinin (WGA) is another problematic lectin, found in wheat. Compared to WGA, gluten is a minor problem. According to Gundry, WGA is one of the most efficient ways to induce heart disease in experimental animals. WGA binds to insulin receptor sites. Normally, a normal hormone will dock on a receptor site, give its information and then release. Pseudo hormones like WGA, on the other hand, dock on the receptor permanently. Gundry explains:
“If they hit the insulin receptor on a fat cell, they turn on lipoprotein lipase and pump sugar into the fat cell, turning it into fat constantly. In muscle cells, the exact opposite happens.
They’ll attach to the insulin receptor in the muscle cell [and] block insulin from delivering sugar into the cell. I see so many long-distance runners who are carboholics, who look like concentration camp survivors because they’re really cachectic and sarcopenic because they block the insulin receptors in their muscles …
The lectins, like WGA and galactans in beans are miraculous ways of making us store fat … [T]he only way we’ve ever been able to fatten an animal for slaughter is to give them grains, beans and some antibiotics. If that’s how we fatten animals, that’s how we fatten us. It works really well.”
Not All Bread Is the Same
If you’ve ever traveled to Europe, you may have indulged in some bread and noticed you didn’t experience the same type of problems you have when eating bread in the U.S. The reason for this is because the lectins are removed when you use traditional methods of raising bread, which is still popular in Europe.
“Europe [has] always used traditional methods raising bread. They use yeast or sourdough. Yeast and bacteria are actually pretty good at breaking down the gluten molecule and other lectins,” Gundry explains.
Europe also does not permit the use of glyphosate to desiccate wheat, which has become common practice in the U.S. Glyphosate is also used on many conventional grains, including beans and flax, so it’s in the animal meats we eat, it’s in our baked goods, and even in wine produced in the U.S. According to Gundry, glyphosate potentiates gluten to people who are not even gluten-sensitive, and interferes with your liver’s ability to manufacture the active form of vitamin D.
Glyphosate also chelates important minerals, disrupts the shikimate pathway, decimates your microbiome and increases leaky gut, which allows more of the LPSs into your bloodstream. Since it works synergistically with the lectins, it really delivers a double-whammy.
“[Glyphosate] hits cytochrome P450. It’s one of the reasons the Europeans are so far [ahead] on health,” Gundry says. “It’s one of the reasons why so many of my patients can go to Europe, eat their traditional diet and think they’re cured and now they can start eating bread. They come back and eat a piece of bread and, bam — the whole thing starts all over again.”
On Vegetarianism and Other Diets
As mentioned, Gundry was a professor at Loma Linda University, a Seventh Day Adventist facility. Seventh Day Adventists are typically vegetarians, and while not an Adventist, Gundry did eat a vegetarian diet for about 15 years during his time there.
“I’ve never been sicker in my life. I used to weigh 228 pounds despite running 30 miles a week and running half marathons on the weekend and going to the gym one hour every day, wondering why I had high blood pressure, prediabetes and heart disease … Quite frankly, we have a fabulous orthopedic department at Loma Linda, because grains are pretty doggone mischievous for that.
Through the years, I’ve been good friends with the head of the Adventist Health Studies, a cardiologist. One of the things I’ve learned from following the Adventists and following Gary Fraser is that … certain animal proteins do contribute to aging. In the Adventist health study, the vegan Adventists have the longest life span. Behind them are the lacto-ovo vegetarians, then behind them are the pescetarians. Then finally, there are the real cheaters who eat chicken …
It is interesting that the longest living of the Adventists, who are very long-living, are the vegans. I take care of a lot of vegans because of my association with Loma Linda. As a general rule, the vegans are some of the unhealthiest people I have met. The reason is they’re grain- and bean-itarians. They are not vegetable eaters.
I have nothing against a high vegetable diet … The other thing we see in the vegans is they somehow think they will convert short-chain omega-3 fats into EPA, the long-chain omega-3 fats. They absolutely and positively do not.
Our brain is about 70 percent fat; 50 percent of that fat is DHA. There are beautiful longitudinal studies showing people with the highest omega-3 index have the largest brains as they age, and the largest areas of memory in the hippocampus. People with the lowest levels of omega-3 index have the most shrunken brains and the smallest areas of memory. Vegans have no excuse anymore. There’s algae-based DHA.”
Fruit and Berries — Seasonal Treats
Gundry’s first rule is that what you stop eating is more important than what you start eating. “It’s absolutely true,” he says. “If you take away certain foods, you’ll be amazed [to find] that it’s certain foods that are the troublemakers.” His second rule is, take care of your gut microbiome. Rule No. 3 is “fruit might be as good as candy.” While he doesn’t expound on the importance of burning fat for fuel in his book, that’s really part of the equation. Once you’re able to burn fat, fruit can be a healthy carbohydrate to add once or twice a week.
“Exactly. I think part of the problem is the vast majority of Americans are insulin-resistant. One of the things that people should realize is that the modern fruit has been bred for sugar content … One of the things I ask people to do initially is give fruit the boot.
Fructose is a major toxin. We take fructose directly to our liver and detoxify it into triglycerides and uric acid. It always amazes me the number of people with gout who consume more concentrated fruit, like wine or beer. Beer is one of the underlying reasons that they have gout.
The other thing people should realize is that fructose is a direct renal toxin. The more fructose I can get out of people, the better. Having said that, once you get to a point where you have metabolic flexibility, I think things like berries are probably one of the best ways to carbohydrate load on the day you decided to do that … Sweet potatoes are great as well, [and] I’m a big fan of taro root.
Years ago [in June] … my wife and I were at a Santa Barbara farmers market. I was taking these gorgeous organic peaches and putting them into my bag. She says, ‘Hey, wait a minute. Aren’t you the guy who says give fruit the boot?’ I said, ‘Yeah, yeah. But it’s June and it’s time to eat fruit.’ She says, ‘OK, smart guy. Let’s do this. This summer, we’re going to give up fruit to see what happens’ …
So, we gave up fruit for one summer. We didn’t change anything else in our diet. My wife lost 6 pounds and I lost 8 pounds. It brought home to me that, again, our ancestors and the reason we have two-thirds of our tongue devoted to sweet taste is we are great fruit predators. Fruit was only available once a year. We utilized that fruit to gain weight for the winter … [Now] we can have it 365 days a year, but that’s not normal. So, always keep that in mind.”
To learn more, I highly recommend picking up a copy of “The Plant Paradox,” especially if you’ve already cleaned up your diet and still struggle with excess weight and/or health problems. Certainly, anyone with an autoimmune disorder would be wise to take a closer look at lectins. It’s really vital information that can help optimize your health, and that of your family. It’s a great read, with the perfect balance between science and practical recommendations.
If you’ve been following the “Fat for Fuel” approach, it’s just a minor tweak. But it’s a very important tweak that I wish I would have known about earlier. If I had, I would have dedicated a chapter to lectins in my book. I will however incorporate this information in my “Fat for Fuel Cookbook,” which will be published this fall.