Lectins, the Plant Proteins Getting a Bad Rap

by karen on July 19, 2019

Fad diets that would have you avoid legumes, grains, certain vegetables, dairy, and some nuts and seeds may be citing lectin as the reason these “toxic” foods need to be avoided. In this day and age, slick websites and high-dollar marketing campaigns, coupled with the MD credential after one’s name, can promote most any half-baked, unscientific idea. And before we know it, there’s another food craze promising to be the end-all, be-all way to prevent disease, lose weight, and maintain a healthy weight.

Scale, Weight Loss, Fitness, Dieting, Health

A Review of the Facts

  • There is no scientific evidence showing lectin-free diets to be healthy
  • Lectin-free diets are not sustainable long-term
  • Initial weight lost on a lectin-free diet will be transient
  • Foods that contain lectins are healthy
  • Science shows diets rich in fruits, vegetables and whole grains are superior for health

What are Lectins?

Lectins are plant-based proteins designed to protect the foods they are found in from predators like insects and other animals. Active lectins may reduce the body’s ability to absorb nutrients and bind to cells that line the digestive tract, a note that has lead to premature theories that lectins cause autoimmune response and play a role in inflammatory conditions like rheumatoid arthritis and type 1 diabetes. Active lectins are found in the raw form of these foods, which means that most of our diets are very low in them. Cooking foods deactivates lectin and renders it harmless, as does fermenting and sprouting these foods. This is where the half-truth is being touted as fact; our diets are not high in raw/active forms of lectin, and cooked/inactive forms of lectin are not of health consequence. These half-truths are the start of unhealthy eating plans and form unfounded food fears.

The highest concentrations of lectins are found in legumes, such as beans, peas, lentils, peanuts and soybeans, as well as grains, fruits and nightshade vegetables, including tomatoes, potatoes, eggplant and bell peppers. Because we eat the vast majority of these foods cooked, consume them without worry of health consequence. And when consuming lectin from foods like tomatoes or bell pepper raw, remember that we have digestive enzymes that keep us healthy by breaking down lectins to their inactive form.

Health Benefits of Foods with Lectin

Legumes, whole grains, fruits and vegetables:

  • help keep blood glucose levels stable
  • are high in fiber and keep us full longer
  • aid in gut health by providing beneficial foodstuffs to our intestinal bacteria
  • contain many vital vitamins and minerals, including vitamin C, potassium and folate
  • have isoflavones that can reduce the risk of cancer and osteoporosis
  • can lower cholesterol levels
  • help reduce the risk of diabetes
  • help protect against overweight and obesity
  • have an abundance of antioxidants that reduce inflammation that leads to disease
  • contain compounds such as chlorogenic acid that can reduce the risk of Alzheimer’s disease

Keep on making plants the basis of your diet, and cross lectins off your list of dietary concerns.


Karen Fisher, MS, RD, LDN, CDE is a dietitian in Reno, Nevada, happily promoting the benefits of healthy foods at her nutrition consulting firm, Nutrition Connection. Find her website atwww.NutritionConnectionNV.com

To find a nutrition expert in your area, go to the academy website – Find an Expert https://www.eatright.org/find-an-expert

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