Whole grain toast with some peanut butter for breakfast, a salad topped with heirloom tomatoes for lunch and a hearty vegan chili for dinner. For most people, these three meals would be proudly entered into MyFitnessPal. But new research may suggest that each of these meals contain a protein that could be wreaking havoc on your health. Lectins, nutritional saboteur or the latest in a long line of weight-loss bogeymen?  

What Are Lectins?

Lectins are a type of protein found in almost all foods. It’s thought that lectins were originally developed by plants to deter animals from eating them. Once eaten, these indigestible proteins bind to cell membranes in the digestive tract, causing discomfort in the gut and serving as a reminder to stay away from the plant.

While lectins’ primary function in nature is to protect plants, a wide variety of uses has been discovered. The most well-known lectin is likely ricin, a poison found naturally in castor beans. At the other end of the spectrum, a lectin recently found in bananas has been reported to inhibit HIV replication. Perhaps it’s this wide range of uses that make it so easy to misunderstand the health benefits and potential drawbacks of lectins and the foods that contain them.

Which Foods Are High in Lectin?


Though found in most foods, only about 30 percent have lectin levels worth mentioning. It’s most abundant in dairy, grains, legumes and nightshade plants like tomatoes and peppers. Quinoa, a lauded “super food,” is packed with lectins, and kidney beans have such high levels that eating just four uncooked beans can cause lectin poisoning, resulting in vomiting, diarrhea and severe nausea.

What’s most interesting about lectin levels in food is how easy it is to drastically reduce them. Boiling, deseeding and peeling are all great ways to reduce lectins to safe levels of consumption. For example, raw kidney beans have 20,000 to 70,000 hemagglutinating units (HAU) of lectin, but that number drops to 200 to 400 HAU when cooked.

Dietary Lectins – A Cause for Concern?

Virtually unheard of just a few years ago, lectins have received a lot of attention lately. Books like “The Plant Paradox” (2017), brought the potential dangers of lectins to the main stage and suggested that a lectin-free diet can mitigate all manner of health issues including acne, autoimmune disorders, weight gain as well as many other chronic health issues.  

However, conventional wisdom suggests there is a simpler way to limit lectins in your diet. The easiest way to reduce lectins in your food is to simply cook your food. For most healthy people, the small number of lectins that remain in properly prepared food will have little to no effect. However, there are a number of medical conditions that may see improvement from a lectin-free diet.  

Who Should Avoid Lectins?

If you have an autoimmune disease, irritable bowel disease, Crohn’s disease, celiac disease or food sensitivities that cause intestinal discomfort, a lectin-free diet may be advisable. There is some research that suggests lectins may cause inflammation, which increases the risk of autoimmune diseases and exacerbates preexisting gastrointestinal conditions.

As with most health-related matters, talking with your doctor is the best first step you can take. Your physician may suggest an elimination diet to see how you respond to a lectin-free lifestyle or provide alternative solutions such as a cannabis-based treatment for symptom management.  

What’s an Omnivore to Do?

For most healthy people, the answer isn’t to avoid lectins, but simply to limit your consumption. To avoid them entirely means to give up many plentiful sources of vitamins, lycopene, iron and fiber. To reduce the lectin in the foods you do eat, peel and deseed your vegetables and thoroughly cook your legumes. As an added convenience, foods that naturally contain high levels of lectins, like canned beans, are pre-cooked before we buy them from the grocery store.

Like most things in life, the lectin debate isn’t black and white. There is still much to discover about this ubiquitous protein. For now, there is ample evidence that a plant-based diet (hold the raw kidney beans), is one of the healthiest ways to live.