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Revisiting Lectins

I think I need to talk about lectins again as I continue to be asked about them. Lectins are a type of protein found in most plants. They play a protective role for plants. Lectins are found in cereal grains, legumes and fruit and are highest in black beans, kidney beans, soybeans and whole grains.

For most people, the benefits of eating lectin-containing foods outweigh any potential negative effects. At high concentrations lectins can be a problem but the amounts typically eaten at one time and the way foods are processed and prepared significantly lowers lectin levels in food. Giving up all lectin containing foods would mean giving up the nutritional advantages lectin containing foods and plant based diets offer.

Lectins can interfere with calcium, iron, phosphorus and zinc absorption. Lectins can bind to certain cells in the lining of the intestine and ultimately pass into the bloodstream and this has given rise to concerns about lectins effects on gut health. However, the only evidence I’m aware of supporting this is in studies that fed isolated lectins or raw beans to animals, mainly rats. Since we don’t eat raw beans or isolated lectins I’m not sure how relevant this is to our daily food choices.

There are things you can do to reduce the amount of lectin in foods. Lectin containing foods should be thoroughly cooked. Lectins are almost completely eradicated by heat and moist heat is the most efficacious. Cooking pasta and beans lowers lectin levels. Boiling beans for 15 minutes, simmering for two hours, and pressure cooking for 45 minutes has been shown to lower lectin levels below detectable levels. So I don't worry about lectins in cooked foods.

Soy, whole grains, and beans, which contain lectins, are healthy foods. These foods give you lots of fiber, vitamins, minerals – all of which are important to a good diet.

There is evidence that consuming lectins could be a problem for people with Rheumatoid arthritis, Crohn’s Disease, and irritable bowel syndrome. People with these conditions should work with a Registered Dietitian Nutritionist to determine if lectins are causing their symptoms and if they should include these foods in their diets.

Photo used with permission from the Journal of the Academy of Nutrition and Dietetics.
Photo taken by Joycelyn Faraj, MS

posted on 8/15/2021