Eating raw foods that contain lectins, such as grains, legumes, and nightshade vegetables, or eating large amounts of them, may cause digestive issues in some people.

Lectins are proteins found mainly in legumes and grains. The lectin-free diet is gaining popularity due to recent media attention and several related diet books hitting the market.

There are various types of lectin. Some are harmless, and others, such as those in kidney beans, can cause digestive symptoms if not cooked properly.

Though quality research is limited, lectins may cause poor digestion, inflammation, and various diseases in some people.

Eliminating lectins from the diet may mean avoiding certain foods, as well as making sure you cook others properly.

This article looks at the health effects of eating lectins, whether you should try a lectin-free diet, and foods to eat and avoid.

The lectin-free diet involves either reducing your intake of lectins or eliminating them from your diet. This may be beneficial for some people with food sensitivities.

Lectins are present in most plant foods but especially high in:

  • legumes, such as beans, lentils, peas, soybeans, and peanuts
  • nightshade vegetables, such as tomatoes and eggplant
  • dairy products, including milk
  • grains, such as barley, quinoa, and rice

The lectin-free diet is restrictive and eliminates many nutrient-dense foods — even those generally considered to be healthy.

Cooking many foods with harmful lectins, such as kidney beans, greatly reduces their lectin content, making them safe to eat. However, cooking other foods, such as peanuts, may not eliminate their lectin content.

The Food and Drug Administration (FDA) recommends boiling beans for 30 minutes to eliminate their harmful lectins.

It’s important to note that it’s rare to eat foods with a high amount of active lectins. This is because they’re usually cooked properly.


The lectin-free diet involves eliminating sources of lectins from the diet, or cooking certain foods properly to destroy lectins before eating them.

Lectins are proteins that bind to carbohydrates. They are present in many plant foods and some animal products.

There’s little research on the effects of different lectins in humans. More research is needed to conclude whether they’re good or bad for human health.

When cooked properly, foods that contain lectins shouldn’t give you any trouble. In fact, a 2015 study found that almost 30% of the food you eat contains lectins.

That said, animal studies suggest that lectins may be an antinutrient, meaning that they can interfere with how well your body absorbs nutrients from food.

Lectins might also negatively affect people with digestive sensitivities or a tendency to experience gastrointestinal distress.

That’s because lectins may exert several effects, including interfering with both your gut microbiota and the absorption of nutrients in your gut, decreasing acid secretion, and increasing inflammation.

Keep in mind that cooking foods that contain lectins, including beans, inactivates lectins and renders them harmless. Soaking beans can likewise reduce their lectin content, though perhaps not enough to ensure safety.

Foods that contain lectin are often full of antioxidants, vitamins, and minerals that improve your health. This is likely to outweigh the negative effects of lectins on the body.


When cooked properly, foods that contain lectins are generally considered safe. However, some people may be sensitive to these foods.

Research has linked lectins with the following negative effects:

Digestive sensitivities

Eating food containing lectins may cause digestive distress in some people.

That’s because the body cannot digest lectins. Instead, they bind to cell membranes lining the digestive tract, where they may disrupt metabolism and cause damage.

People with an underlying digestive condition, such as irritable bowel syndrome (IBS), may experience negative effects after eating antinutrients like lectins.

It makes sense to avoid any foods that you identify as causing digestive problems. If you experience digestive discomfort after eating certain foods, consult your doctor and avoid eating foods that cause discomfort.


Different types of lectin have various effects on the body. Some are highly toxic, including ricin, a toxin derived from castor beans. Meanwhile, others are harmless.

It’s important to avoid raw, soaked, or undercooked beans. These can be toxic.

For instance, phytohemagglutinin, a lectin high in kidney beans, can cause extreme nausea, severe vomiting, and diarrhea after eating just 4 or 5 raw beans.

The FDA states that raw kidney beans contain 20,000–70,000 hau, while fully cooked beans contain a safe amount of 200–400 hau.

Soaking beans isn’t enough to remove lectin. However, cooking beans for 30 minutes can destroy the lectins and make the beans safe to eat.

Slow cooking is not recommended, as slow cookers may not reach temperatures hot enough to destroy the toxin.

May damage the digestive tract

Some research states that lectins can disrupt digestion, interfere with nutrient absorption, and cause intestinal damage if eaten in large quantities over a prolonged period of time.

That said, research in humans is limited, and more studies are needed before the true effects of lectins in humans are fully understood.


High lectin foods are generally considered safe as long as they’re cooked properly. However, research is mixed.

Common foods that contain lectin are generally considered safe for most people to eat as long as they are cooked properly.

People with digestive sensitivities might experience negative effects after eating these foods. It makes sense to avoid any foods that cause digestive problems for you.

That said, there are various things to consider before trying a lectin-free diet.

Nutritional deficiencies

Many healthy foods are implicated in the lectin-free diet. The diet is lacking in broad-based nutrition, including fiber.

Foods that contain lectins, such as beans and certain vegetables, are often good sources of vitamins, minerals, and antioxidants. Eating these foods is likely to benefit your health, outweighing the negative effects of lectins.

Research in humans is lacking

Research on lectins and their effects on people is currently sparse.

Most of the studies have been conducted on animals, not humans. Research has been largely performed in vitro. This means it has been conducted with isolated lectins in laboratory dishes or test tubes.

More research is still needed before scientists know the true effects of lectin in the diet.

Claims may be biased

Make sure to take a critical approach when researching this food plan. Many websites that promote it are trying to sell products.

Look for science-based evidence instead of inflated claims on websites that sell cookbooks or supplements geared toward helping you achieve lectin-free health. Some may be what they claim to be, but others may not.

For example, there are claims that lectins promote weight gain, but multiple studies, such as a 2016 study on pulse consumption, indicate a weight loss effect.


The lectin-free diet is not necessary for most people, and it comes with risks. For some people with food sensitivities, reducing lectins may help.

All plant and animal products contain some lectins. Yet, fruits and vegetables that contain relatively little lectin include:

  • apples
  • artichokes
  • arugula
  • asparagus
  • beets
  • blackberries
  • blueberries
  • bok choy
  • broccoli
  • Brussels sprouts
  • cabbage
  • carrots
  • cauliflower
  • celery
  • cherries
  • chives
  • collards
  • cranberries
  • kale
  • leafy greens
  • leeks
  • lemons
  • mushrooms
  • okra
  • onions
  • oranges
  • pumpkins
  • radishes
  • raspberries
  • scallions
  • strawberries
  • sweet potatoes
  • Swiss chard

You can also eat all forms of animal protein on the lectin-free diet, including:

  • fish
  • beef
  • chicken
  • eggs

Fats, such as those found in avocados, butter, and olive oil, are allowed on the lectin-free diet.

Many types of nuts, such as pecans, pistachios, pine nuts, flax seeds, hemp seeds, sesame seeds, and Brazil nuts, are also allowed.

Some kinds of nuts contain lectins, including walnuts, almonds, and sunflower seeds.


While most plant foods contain lectins, you can choose to eat low lectin alternatives, such as broccoli, sweet potatoes, and strawberries.

The foods highest in lectins include:

  • 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
  • many dairy products, such as milk

While cooking removes lectins from some foods, such as kidney beans, it may not remove lectins from others, such as peanuts.


On the lectin-free diet, people may avoid legumes, nightshade vegetables, grains, and peanuts.

When following any restrictive diet, including the lectin-free diet, it’s important to make sure you get enough nutrients from the other foods you eat.

Many of the foods that are eliminated on this food plan are high in dietary fiber, which is beneficial to health. Make sure to either eat enough fruits and vegetables or take a fiber supplement to compensate.

Here are some tips to remember when following the lectin-free diet:

  • Soaking and boiling beans reduce their lectin content.
  • Fermenting or sprouting grains and beans can also help reduce their lectin content.
  • Try an elimination diet to see if you have a food sensitivity to some lectin-containing foods. To do this, remove one food at a time and check whether your symptoms improve.
  • If possible, talk to a doctor or dietitian to make sure you’re getting your full range of nutrients each day.

If you try out the lectin-free diet, make sure you’re getting enough nutrients from other food sources.

Most foods contain some lectins, especially legumes and grains.

Consuming raw foods that contain lectins, or eating large amounts of them, might negatively affect your digestion and nutrient absorption.

Scientific research on how lectins affect humans is lacking. However, some animal studies indicate that a lectin-free diet might be beneficial for some people, such as those with digestive sensitivities.

If you’re experiencing discomfort after eating, consult your doctor or dietitian.

Also, if you’re considering starting a lectin-free diet, it’s a good idea to consult your doctor or dietitian, especially if you’re pregnant or have an underlying health condition.

Make sure to take a critical approach when researching this food plan. Many websites that promote it are trying to sell products.