Lectin: The common link of proteins between peas and people

Last Updated December 20th, 2021

What Are Lectins?

Lectins are plant-based proteins that have been linked with both positive and negative health effects. They help cell interaction in humans and provide a form of defense mechanism in plants. They also help in plant growth due to the presence of nitrogen. Though several parts of the plant contain lectin, still only the seeds of the plants are used widely for consumption.

When taken in smaller amounts lectins play important roles in body processes, including immune function and cell growth. However, larger amounts of consumption can lead to adverse reactions, such as gut wall damage, diarrhea, vomiting, and impaired functionality in absorbing nutrients.

Several studies have brought to light that the lectins bind to cells on the gut wall and trigger a response. This form of cell communication can even play a significant role in cancer therapy. The abundant sources of lectins are available in legumes, grains, and nightshade vegetables.

Healthy Foods That Are High In Lectin

Red kidney beans

Red kidney beans are one among the richest sources of plant-based protein. Apart from providing protein they also enrich the body with carbs that are low on the glycemic index (GI). They possess the capability to release their sugars slowly into the bloodstream and avoid a sudden spike in blood sugar levels. They also contain resistant starch and insoluble fiber, which play a vital role in weight loss and help improve gut health.

These beans also contain several mineral and vitamins such as iron, potassium, folate, and vitamin K1. However, it is advisable to avoid eating these beans raw as they can cause nausea, vomiting, and diarrhea due to high levels of lectin. When cooked properly they are a nutritious food that is a valuable addition to your diet.


Soybeans are one of the most essential sources of protein. They are particularly a much-needed food for vegetarians as they are abundant sources of plant-based proteins. They are a good source of vitamins and minerals, particularly molybdenum, phosphorus, and thiamine. The presence of isoflavones (a crystalline compound whose derivatives occur in many plants, especially in pulses) in soybeans are linked to cancer prevention and also help reduce the risk of osteoporosis.

Similar to red kidney beans, soybeans also contain high levels of lectins. It is, therefore, necessary to cook them well at high temperature. On the other hand, another proven method to reduce the level of lectins is fermentation and sprouting. Fermented soybean products include soy sauce, miso, and tempeh. The sprouts of soybeans are widely used in salads or stir-fries.


Wheat is one of the widely used foods across the world. In fact, it is used by 35% of the world’s population. Whole wheat consists of high fiber content and has proved to be beneficial to gut health. It also contains a high glycemic index (GI) which can lead to a sudden increase in blood sugar levels. Some individuals find it difficult to digest wheat due to the presence of gluten (a type of protein found in wheat). On the other hand, it is also a good source of several vitamins and minerals, such as selenium, copper, folate, and ferulic acid (an antioxidant in whole wheat).

The ferulic acid in whole wheat has been linked to a reduction in heart disease. Wheat germs are high in lectin and it is mandatory to cook them well in order to eliminate the excess levels of lectin. Several studies have shown that most of the store-bought wheat products contain low levels of lectin since it’s usually removed during heat treatment.


Peanuts are categorized under legumes and are related to beans and lentils. They provide a great source of energy due to high levels of mono and polyunsaturated fats present in them. They also contain high levels of proteins, vitamins, and minerals, such as biotin, vitamin E, and thiamine.

These nutrients make peanut an antioxidant and the consumption of it has been linked to reducing the risk of heart disease and gallstones (a small, hard crystalline mass formed abnormally in the gall bladder or bile ducts from bile pigments, cholesterol, and calcium salts). Unlike the above-mentioned foods, the lectin level in peanuts cannot be reduced by heating. And research is underway to prove its beneficial qualities.


These bright red companions are a part of the nightshade family, which also include eggplants and bell peppers. Tomatoes are high in fiber and rich in vitamin C, potassium, folate, and vitamin K1. The compound lycopene (a red carotenoid pigment present in tomatoes and many berries and fruits) present in tomatoes helps reduce inflammation and heart disease. An array of studies has also proved that it can also help protect the body against cancer.

Studies have found that tomato lectins possess the tendency to cross the gut and enter the bloodstream. As a result, some people react to the intake of tomato. The reaction is mostly related to pollen-food allergy syndrome or oral allergy syndrome. It should also be avoided by people who carry rheumatoid arthritis genes, as the consumption of tomato can increase the risk of the disease.


They are another tasty nightshade vegetables which are quite popular in many cuisines. They are eaten in varied forms and are a good source of some vitamins and minerals. They contain high levels of potassium and are good sources of vitamin C and folate. When eaten with the skin they provide antioxidant properties due to the presence of chlorogenic acid. This compound helps in the reduction of heart disease, type 2 diabetes, and Alzheimer’s disease.

It has also played a role in weight loss by maintaining a feeling of fullness. It is important to keep in mind the way it is cooked. They are high in lectins which appear to resist heat. Even after cooking 40-50% of the lectins are retained in them. Like tomatoes, some people have experienced adverse effects when they eat potatoes. However, researches are yet to prove the same and it is proved that certain varieties of potatoes are linked to reducing inflammation.

Is Lectin Good Or Bad For You?

Excessive amounts of lectin are indeed harmful and can lead to gastrointestinal distress, loss of muscle strength, etc. They may impact your health negatively and cause you to develop symptoms associated with food sensitivity. In order to acquire the necessary nutrients and maintain a healthy lifestyle, it would be advisable to follow a lectin-free diet.

Large amounts of lectin can cause the following disruptions:

  • Intake of large amounts of lectin can lead to gastric distress as it is not easily digested. It has the capability to bind to the cell membranes lining the digestive tract. This characteristic may disrupt metabolism and cause damage.
  • It increases the growth of bacteria in the small intestine and alters the mucous defense layer. This increases the risk of peptic ulcer.
  • It interacts with the digestion process and causes intestinal damage when consumed over a prolonged period of time.
  • They are titled as antinutrients since they block the absorption of some nutrients.
  • The large intake of lectin can lead to health problems ranging from digestion to chronic diseases.

Lectin-Free Diet

The lectin-free diet is a diet that avoids excessive consumption of lectin and encourages the consumption of alternative food choices. The plan also includes supplements and is beneficially in improving health.

Setbacks of a lectin-free diet

A lectin-free diet is a restrictive diet plant that could make it difficult for you to receive all the essential nutrients. The plan could be healthy but to a limit. This diet cuts down several nutritious foods, such as whole grains, beans, and certain vegetables. It is a diet which may be difficult for vegetarians or vegans to follow since it eliminates the use of legumes, nuts, seeds, and whole grains. When looking at it in a commercial spectrum, it may be questionable as it is quite expensive as it contains specialty milk, pasture-raised meats, and other expensive supplements.

Foods On The Low End Of The Lectin Scale

As mentioned earlier, lectin is a protein present in several plants and animal products. However, there are some fruits and vegetables that contain a lower level of lectin, they are

  • Onion
  • Broccoli
  • Cauliflower
  • Mushrooms
  • Pumpkin
  • Sweet Potato
  • Carrots
  • Asparagus
  • Cherries
  • Apples
  • Blueberries
  • Strawberries
  • Oranges
  • Lemons
  • Cherries
  • Fish
  • Beef
  • Chicken
  • Eggs
  • Avocados
  • Butter
  • Olive Oil

Food On The High End Of The Lectin Scale

Below mentioned foods contain high levels of lectin

  • Nightshade vegetables, such as tomatoes, potatoes, goji berries, peppers, and eggplant.
  • All legumes, such as lentils, beans, peanuts, and chickpeas.
  • Peanut-based products, such as peanut butter and peanut oil.
  • All grains and products made with grain or flour, including cakes, crackers, and bread.
  • Dairy products, such as milk.

Guidelines To Maintain A Healthy Lectin Intake

If you feel that you would love to go lectin free, then it is advisable to adhere to fruits, vegetables, and animal products that are low in lectin.

  • Prepare foods that contain lectin in a pressure cooker to lower the levels of lectin. They have the tendency to attach themselves to carbohydrates and are removed from the body before they can cause any ill effect.
  • The best ways to remove excessive lectins in food are boiling, fermentation, sprouting, peeling, deseeding, and pressure cooking.
  • Soak and boil beans to reduce the lectin content present in them.
  • Grains and beans can be fermented and sprouted to reduce their lectin content.
  • Always make a trial-and-error approach before consuming lectin as you can develop gastric complications.
  • Make sure to substitute a high fiber content diet in order to maintain healthy digestion.
  • Before you consume the foods with lectin make sure to consult your doctor or dietitian.

Lectins in a nutshell

Lectins are a type of carbohydrate-binding protein that plays a role in the digestive tract. They are abundantly available in plants and animal products. The specific foods that contain higher levels of lectin are legumes, nightshade vegetables, dairy products, and grains, such as barley, quinoa, and rice. Some types of lectins, such as ricin, are toxic, but others are not. People with food intolerance to lectin can opt for a lectin-free diet without having to lose the essential nutrients.

Care should be taken not to eliminate lectin suddenly from your diet. The levels of lectin in food aren’t at present of any health concern and are considered healthy. They’re also important sources of vitamins, minerals, and antioxidants. In smaller amounts, they provide numerous health benefits but larger amounts can reduce your body’s ability to absorb nutrients. Cooking methods that involve moist heat are helpful in decreasing the number of lectins in plants.


  1. https://www.healthline.com/nutrition/foods-high-in-lectins
  2. https://www.medicalnewstoday.com/articles/319593.php
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1115436/
  4. https://www.healthline.com/health/lectin-free-diet#takeaway
  5. https://www.healthline.com/health-news/kelly-clarkson-diet#1


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