Is eliminating lectins healthy or unhealthy?
Grilled Polenta Vegetables with Lemon-Caper Vinaigrette

The Lectin-Free Diet: Healthy or Not?

You may not have heard of the "lectin-free" diet, but you probably know people who avoid eating legumes, whole wheat and nightshades because they're trying to avoid lectins.

But what, exactly, are lectins? And should you be following a diet that restricts or eliminates lectins? That depends. Here's a little bit more information to help determine whether or not you need to be paying attention to the lectins in your diet.

What are lectins?

Lectins are proteins that bind to other carbohydrates. They've been referred to as "anti-nutrients" because they aren't digestible in the human gastrointestinal tract, and could potentially prevent your body from absorbing key minerals like calcium, iron, phosphorus and zinc.

Lectins also attach to the cells lining your intestines and can stay there for a fairly long period. Because of this, lectins have the potential to cause an autoimmune response—and this is, in part, what's fueled an anti-lectin movement (for proof, check out the popularity of the paleo diet and the Whole30 diet, both of which eschew many lectin-containing foods).

What is the Lectin-Free Diet?

The Lectin-Free Diet was developed by Steven Gundry, M.D., a former cardiothoracic surgeon at California's Loma Linda University Medical Center and the founder of the Center for Restorative Medicine in Palm Springs, California. Gundry believes lectins are responsible for numerous physical discomforts, and that they also may cause leaky gut syndrome, where holes develop between the cells lining your GI tract. When the cells lining your intestines are compromised, they can't keep inflammation-triggering toxins and bad bacteria out of your body—nor can they keep good things like nutrients in. There's strong evidence that leaky gut may cause food allergies, inflammatory disease and celiac disease, which are often marked by unpleasant symptoms like nausea, vomiting and diarrhea.

So, what foods are high in lectins?

All plants contain lectins. In nature, lectins serve as a kind of protective measure for plants, as they aren't digestible, and thus should be unappealing to would-be consumers like animals and humans. That strategy hasn't actually worked though, as lectins are still present in about 30% of the food we eat.

That said, lectin levels vary. They're highest in raw legumes—such as peas, beans, lentils, soybeans and peanuts—and in whole grains such as wheat, which contains some of the highest lectin levels in the plant world.

Nightshade vegetables (eggplant, tomatoes, peppers, potatoes and seed spices), squash and fruit are also higher in lectins, which has led many lectin-free diet promoters to advocate for avoiding these foods.

What foods are low in lectins?

According to Gundry, these foods are low in lectins and OK to eat on a lectin-free diet.

  • Avocado
  • Asparagus
  • Broccoli, Brussels sprouts and other cruciferous vegetables
  • Celery
  • Cooked sweet potatoes
  • Garlic
  • Leafy green vegetables
  • Mushrooms
  • Onion
  • Pasture-raised meats

Should I avoid eating lectins?

Probably not. Most health experts point out that the research around lectins and the harmful effects of consuming what are called "active lectins" (such as those found in raw beans) is limited. We don't actually eat many active lectins because we rarely consume foods containing high amounts of lectins raw. Soaking or sprouting high-lectin foods deactivates the lectins, as does cooking them with high heat (boiling, stewing, etc.). This is one of the main reasons why we cook (and sometimes also soak) beans—raw beans are full of active lectins that will upset your stomach. Fermentation is a third way to deactivate lectins.

Plus, the benefits of eating foods that are high in lectins, such as whole grains and beans, largely outweigh the potentially negative effects for most people. Legumes provide fiber, protein, magnesium and zinc, and may protect against diabetes, high blood pressure, heart disease and inflammation, while research shows that eating whole grains increases longevity and reduces your risk of several chronic diseases.

"If you're healthy, there is no reason to be afraid of lectins. Lectins are found in foods that are tied to a reduced risk of obesity and chronic diseases, and an increase in longevity," says Cynthia Sass, RD, CSSD, a virtual-plant based performance nutritionist. "In fact, in the areas in the world where people live the longest, healthiest lives (with low rates of obesity and chronic disease), high-lectin foods are staples, including pulses and whole grains."

Some people should consider avoiding lectins

If you have irritable bowel syndrome (IBS) or another digestive sensitivity, you may be more likely to experience negative effects from eating lectins. Also, if you have an autoimmune condition or food sensitivities, higher-lectin foods may exacerbate inflammation, says Sass.

But if you already know you have certain food-based triggers, you'll probably be better served by working with a registered dietitian to determine if you need to eliminate lectins. A dietitian can also create an individualized plan to ensure that you don't miss out on fiber and essential nutrients if you're avoiding many foods that are naturally high in them.

The bottom line

Unless you have a specific sensitivity to lectin-containing foods, there's no reason to cut foods with lectins out of your diet entirely. Beans, whole grains and other vegetables with lectins provide many boons to our health, so unless you have a specific reason to avoid them, you'll reap the benefits in vitamins, nutrients and disease prevention.