Lectins: The New Health Villian?

The media and the public have an insatiable appetite for controversy which is why dubious ideas often get a lot more traction than they deserve. This is particularly true when it comes to health fads, which can sometimes be little more than pseudoscience wrapped up in catchy phrases and clever marketing.

“The Plant-Paradox” Unfairly Vilifies Lectins

There are plenty of fashionable wellness trends don’t stand up to scrutiny. A case in point is a new book titled “The Plant Paradox,” by Dr. Steven Gundry, which villainizes lectins (a plant-based protein found in legumes) that humans have been safely consuming for thousands of years.

Lectins are found in virtually every food we consume, but they are more abundant legumes, grains, and nightshade vegetables. They are a type of protein that binds to cell membranes in ways that help regulate (and modulate) intracellular activities (including both inflammation and immune response). Lectins play such an important role in our bodies that they are considered to be the first-line of defense against bacteria and microorganisms.

Botanists believe that lectins evolved as a type of plant-based “defense mechanism” to discourage insects and animals from nibbling on leaves. Like caffeine, which can be toxic to small pests that feed on tea leaves (or coffee plants), but pleasurable in small doses for humans, lectins can have both beneficial and potentially adverse properties. As a whole, though, human beings have evolved in ways that harness the beneficial qualities of lectins.

The Health Benefits of Lectins

Studies show that both lectins and lectin-rich foods can stimulate the immune system. Research also suggests that they can also ward off viruses and they may even help block some forms of cancer. Most lectin-rich foods are loaded with nutrients, minerals, antioxidants, and fiber.

Nevertheless, overexposure to lectins can irritate the GI tract in some people. This is why we should not eat uncooked (or undercooked) beans. But this problem can be avoided by cooking… something that humans figured out thousands of years ago. That said, the collective voices of the majority of nutrition experts agree that the health benefits of lectin-rich foods far outweigh the relatively minor risks. Dr. Gundry’s hyperbolic assault on lectins dispenses with any sense of balance by making unsubstantiated claims that lectins are the source of most — if not all — human diseases.

On his website, Gundry writes, “I believe lectins are the #1 Biggest Danger in the American Diet.” In my opinion, Gundry is big on sweeping assertions but skimpy on the kind of scientific proof that would back it up. He insists that eating a plant-based diet will “incite a kind of chemical warfare in our bodies, causing inflammatory reactions that can lead to weight gain and serious health conditions.” He then goes on to link lectins to virtually every disease under the sun. Suggesting that plant-based diets are dangerous…is dangerous advice.

Dr. Gundry Versus the Facts

The preponderance of evidence disagrees with Dr. Gundry’s assertions. Let’s begin by looking at some facts.

  • Studies of Blue Zones (geographic regions where people live the longest and healthiest lives) show that legumes and lectin-rich foods are widely consumed. That’s right, the empirical evidence is clear — communities that have the highest percentages of centenarians — such as  Okinawa (Japan); Sardinia (Italy); Nicoya (Costa Rica); Icaria (Greece) and Seventh-day Adventists in Loma Linda, California — eats lots of beans, peas, and lentils (the very foods Dr. Gundry demonizes).
  • One of the most comprehensive nutritional studies ever conducted — the Pure Study — found that “healthiest people in the world had diets that are full of fruits, beans, seeds, vegetables, and whole grains, and low in refined carbohydrates and sugar.”
  • Lectins are used in medicine to treat cancer and other diseases.

By the way, my friend and colleague Dr. Joel Kahn was on television with Dr. Gundry recently and you can check out his well-articulated rebuttal for yourself in this video. In my view, Dr. Kahn’s fluency (and Dr. Gundry’s loss of words) speak for themselves.


I worry that the hype surrounding the “Plant-Paradox” will encourage people to eat a bad fad diet. Dr. Gundry’s recommendation that people replace legumes with cheeses and saturated fats runs counter to the best scientific evidence on nutrition that we have.

People have been eating legumes and other sources of lectins for centuries if not thousands of years. Very high amounts of lectins over long periods of time can cause gut irritability in some people, but ordinary cooking methods almost always reduce these proteins to safe levels.

I think it’s unwise to suggest that most healthy people should give up lectin-rich foods such as legumes. That’s because beans, grains, and nightshade vegetables have so many beneficial nutrients, minerals, and antioxidants. From my perspective, Dr. Gundry’s extreme prescription is not the kind of advice that’s worth heeding.

Take good care,

Dr. Josh