Are lectins bad for you? Why you shouldn’t worry about consuming them

by | Jun 22, 2022 | IBD | 5 comments

Do you sometimes experience digestive problems or irritation after eating some foods? If you notice whole grains, beans, or “nightshade” vegetables trigger some discomfort, lectins, a substance of these foods, maybe the leading cause.

Lectins are proteins found in all plants but are in large amounts in nuts, legumes, seeds, wheat, and some veggies. Commonly referred to as an “anti-nutrient,” lectins prevent the absorption of certain nutrients. This is a feature that lectins use to protect plants in nature. However, while this defense mechanism works great for plants, it doesn’t always work well for your gut.

Since lectins block the absorption of important nutrients and can cause gut problems shouldn’t they be avoided? Well, not so fast. Lectins are known for getting a bad reputation, but did you know they also have health benefits when prepared correctly?

If you’ve been unsure about including or excluding lectins in your diet, keep on reading to learn more!

Why are lectins not good?

Lectins resist being digested and are very stable in an acidic environment, a feature that defends these plants in nature. If you take them in their active state, they can lead to adverse side effects. In fact, eating raw kidney beans can cause food poisoning since it contains a high amount of “phytohemagglutinin.” A kind of lectin that may cause red blood cells to clump together. It may also cause vomiting, nausea, diarrhea, and stomach upset. Other side effects are bloating and gas.

Studies on animal cells have found that lectins can affect the absorption of minerals, especially iron, calcium, phosphorus, and zinc. Cereals and legumes contain these minerals, so the presence of lectins can prevent the use and absorption of these elements in your body. 

Furthermore, lectins can bind to cells, thus lining your digestive system. This can affect the breakdown and absorption of nutrients into your body. Since lectin bind to cells for an extended period, it can cause an autoimmune and is believed to cause inflammatory conditions such as type 1 diabetes and rheumatoid arthritis.  

Why you should consume lectins

Are lectins bad for you? Although eating too many foods containing lectins can cause serious side effects on your health, they also play vital roles in your body. Lectin help regulate cell adhesion and play a role in immune function and the synthesis of glycoproteins.

Lectins play a role in immune regulation, and studies show that they might have antimicrobial elements. Actually, they have shown to be more effective against various types of bacteria. Lectins might also help fight viral infections and fungi, with some research showing that they may block the growth of fungus that causes yeast infection. 

Other studies show that some lectins may possess anticancer properties too. Based on a 2015 review published in Cell proliferation, lectins can modify the expression of particular immune cells and signaling pathways to help kill cancer cells and avoid tumor growth.

In many extensive population research, foods containing lectins such as legumes, nuts, and whole grains are linked to weight loss, low rates of cardiovascular disease, and type 2 diabetes.

Also, lectins can act as an antioxidant, protecting body cells from damage caused by free radicals. Furthermore, lectins help slow down the digestion and absorption of carbs, preventing high insulin levels and sharp rises in blood sugar.

Some early research is looking at using small amounts of lectins to stimulate gut cell growth in people who cannot eat for long periods. 

How to consume lectins

Even though lectins have some side effects, you don’t need to cut out these foods from your diet. When you prepare the food properly, you can reduce the lectin level. After all, consuming foods containing a high level of active lectins is rare because of the potent taste. 

Cooking methods such as stewing, boiling, or soaking in water for a few hours can render most lectins inactive. Lectins are generally found on the outer side of food, and they are water-soluble, so soaking them eliminates them. 

Cooking, soaking, sprouting, and fermenting can also be effective ways to eliminate lectin content. Sprouting (germination) involves soaking seeds for up to 24 hours and then rinsing and drying them for a few hours for some days. Apart from decreasing the amount of lectin in your legumes and grains, sprouting enhances the nutritional content of your foods. It also helps reduce the number of other antinutrients that might interfere with digestion.

Fermenting foods can help minimize the level of lectin content. Fermenting food allows the beneficial bacteria to break down the lectins and other antinutrients. Add some beneficial bacteria or leftovers from previous fermented food to kick-start the fermentation process. Typically, fermented food has a pleasantly sour taste and, at times, fizzy quality, and it can be a great source of probiotics.

Also, canned beans are prepared and packed in liquid, so they are low in lectins. But raw beans cooked under low heat or undercooking won’t eliminate all the lectins.

Your body can produce enzymes that help damage some lectins. Another way to deactivate lectins is to remove the outer cover of wheat and beans grains physically. The outer shell has a high amount of lectins.

If you want to eliminate lectins from potatoes or tomatoes, breaking out the pressure cooker might be best. Just add water, cover it and start cooking. 

Consumption of legumes, nuts, grains, and vegetables is associated with positive health outcomes. Foods such as legumes contain dietary fiber that is essential to your body. In fact, according to a study, people that don’t restrict fiber are 40% less likely to flare in inflammatory bowel disease (IBDs). And those that consume whole grains similar to fiber were less likely to flare. However, it’s essential to take a reasonable amount, especially if you usually experience adverse effects after eating food rich in lectins.

Bottom line

Nuts and whole grains are rich in proteins, vitamin B, and fiber, associated with better outcomes in those who consume them. Cooking and soaking eliminate most lectins, minimizing them to a low enough level for consumption. This makes them safe to consume.

But if you usually experience constant discomfort after eating foods containing lectin, consider talking to the Crohn’s and Colitis Dietitians. Click here to learn more about our personalized nutrition plans. If you have any questions, contact us today, and we will be glad to assist you.

Ashley and Leah, talk with an IBD dietitian today

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  1. Karen


    It’s so confusing with all the varied information from experts.

    I would appreciate a complementary call from a licensed certified nutritionist.

    My primary concern is to turnaround my overall health and to focus on restoring back my Body Mass Index ( BMI)& restoring back my 140 pound weight to support my 5feet 9 inch height, in healthy ways. Will you help please. Of course there is more to share about my overall health concerns.Thank you!

  2. Ari

    Excellent article and explanations! Thank you!

  3. Lucy

    Ashley I am an Aussie Mum and have had UC for 12 years. I love your posts and thank you from the bottom of my heart for the information you are sharing with us.

    • Ashley Hurst, R.D.

      Thank you Lucy!



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