Lectins are a group of proteins present in abundance in legumes and grains. They can also be found in nearly all foods. Some of lectins are harmful, while most of them are beneficial to your health.

Evidence suggests that plants produce lectins as a way of survival. For this reason, some people claim that lectins can be harmful, especially when consumed in excess. They say that it can increase gut permeability and cause autoimmune diseases. While these claims are true, proper cooking of foods containing lectins can degrade or even completely remove lectins. This article will discuss all you need to know about lectins and foods containing them.

What Are Lectins?

Lectins are found in all foods, including plants and animals. Lectins are typically protein in nature and perform several psychological functions, especially those derived from animals. In plants, lectins help protect the plant against insects. Some lectins such as ricin from castor oil are toxic and may even affect your health negatively. Lectins are mostly found in plants with soybeans, beans, and peanuts containing most of them. Nightshade plants and grains follow in the list.

Some Lectins Are Toxic and Harmful

Not only animals but also humans find it a challenge to digest lectins. Published studies indicate that lectins are highly resistant to the enzymatic actions in your digestive system. In most cases, lectins will pass through your stomach as intact as they were. Edible plants containing lectins are not to be worried about. However, a few of them can be harmful, for example, phytohemagglutinin found in raw kidney beans. This is a toxic lectin that causes kidney bean poisoning with symptoms like diarrhea, abdominal pain, and vomiting. To avoid such poisoning, it would help if you cooked your kidney beans properly.

Cooking Denatures Most Lectins

Followers of the paleo diet completely avoid legumes and grains from their diet, claiming that they contain lectins. Lectins can be degraded to nothing through proper cooking, anyway. Boiling beans and other legumes in water is the best way to completely eliminate lectins. Usually, raw red kidney beans are loaded with approximately 70,000 hemagglutinating units (HAU), while properly cooked red kidney beans contain approximately 400 HAU. One study indicated that almost all lectins in soybeans could even be removed by cooking for only 10 minutes. Alternatively, you can reduce lectins in various foods by sprouting or fermenting.

Foods Containing Lectins

Lectins are found in almost every kind of food you eat. When consumed in small quantities, lectins can benefit your health, including lowering the risk of certain types of cancer and boosting immunity. Taking too much of these compounds can block some nutrients from being absorbed. Below are some foods that contain lectins.


Soybeans are an excellent source of protein, providing high-quality plant-based proteins. They are, in fact, a good food alternative for vegetarians. Copper, molybdenum, riboflavin, magnesium, and manganese are some of the vitamins and minerals you can obtain from soybeans. Additionally, the consumption of soybeans has been linked to the prevention of cancer and lowered risk of osteoporosis. This is because they contain powerful plant compounds known as isoflavones. Similarly, soybeans can also help reduce the likelihood of developing heart disease, type 2 diabetes, and obesity by lowering cholesterol.

On the other hand, soybeans are also high in lectins. To eliminate these lectins, you must ensure that you cook soybeans properly at a high temperature. According to published studies, lectins in soybeans can be completely eliminated within 10 minutes by boiling them at 100 degrees Celsius. Additionally, you can ferment or sprout soybeans to reduce or eliminate lectins. Tempeh, miso, and soy sauce are examples of fermented soybeans.

Red Kidney Beans

This is another great source of plant-based protein. Red kidney beans are also high in carbs which score low on the glycemic index (GI). GI measures how fast one food can increase sugar levels in the blood. Therefore, carbs in red kidney beans release sugars slowly into the bloodstream leading to a gradual increase in blood sugar levels. These beans also are in high resistant starch and insoluble fiber, both of which promote weight loss and support gut health. They also contain vitamins and minerals like folate, iron, potassium, and vitamin K.

However, high levels of lectins are in raw kidney beans. They contain phytohaemagglutinin, a lectin that, when ingested, can cause diarrhea, vomiting, and nausea. You can enjoy the nutritional value of red kidney beans when they are properly cooked.


Peanuts fall in the same category of legumes with lentils and beans. They are a good source of energy due to their content of monounsaturated and polyunsaturated fats. By consuming peanuts, you increase your intake of vitamins and minerals like thiamine, biotin, and vitamin E. They also provide antioxidants that reduce cellular damages caused by oxidative stress and reduce the risk of heart disease and biliary disease. That said, peanuts contain lectins which, according to studies, cannot be reduced by cooking. It is claimed that lectins in peanuts can promote the growth of cancer cells because they enter your bloodstream unchanged.


Tomatoes, potatoes, bell peppers, and eggplants are the common varieties of the nightshade family. Tomatoes are rich in fiber and vitamin C. One ripe tomato provides up to 20% of the recommended daily intake of vitamin C. Decent amounts of folate, potassium, and vitamin K are also found in tomatoes. What’s more, tomatoes provide high amounts of lycopene. This compound may help reduce inflammation, heart disease, and certain types of cancer.

Tomatoes, however, contain lectins, and there is no evidence to show that these lectins can affect your health.


Lectins are a group of proteins that are found in animal and plant foods. In humans, lectins can help reduce the risk of many diseases, including heart disease and cancer. In plants, lectins help protect them from insects and herbivores. In general, lectins are toxic, and consuming them can cause nausea, vomiting, diarrhea, and abdominal pains. Foods like red kidney beans and soybeans must be cooked properly to eliminate lectins.

MS, Durham University

The work of a family doctor includes a wide range of clinical diversity, which requires extensive knowledge and erudition from a specialist. However, I believe that the most important thing for a family doctor is to be human because the cooperation and understanding between the doctor and the patient are crucial in ensuring successful health care. On my days off, I love being in nature. Since childhood, I have been passionate about playing chess and tennis. Whenever I have time off, I enjoy traveling around the world.

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