Are Lectins Bad For You?

Have you heard of lectins? Or the lectin-free diet?

Lectins, and whether or not you should be eating them, is a subject of much debate.

If you’re wondering what the heck lectins even are, whether or not lectins are bad for you, and what the lectin-free diet is, this article has got you covered.

What Are Lectins?

Lectins are proteins found in a wide range of commonly consumed foods, especially plant foods.

Foods high in lectins include:

legumes such as beans, lentils, peas, soybeans, peanuts, etc.
nightshade vegetables such as eggplants, peppers, tomatoes, potatoes, etc.
grains such as wheat, barley, rice, oats, quinoa, etc.
seeds and nuts

Lectins are found in all plants, where they function to protect and defend the plant.

Lectins are also found in all animals (including humans) where they have many physiological functions, however this article is discussing dietary lectins which are the lectins coming from the plant foods we humans eat.

One of the most important features of lectins is their ability to survive human digestion. When foods containing lectins are ingested, the lectins are able to resist the acidic conditions of the digestive tract and avoid being digested.

Further research is still needed to properly determine the effects of lectins in the human diet and whether they should be avoided or not.

Based on current research (mostly animal studies), here are some ways that lectins may be associated with negative health effects:

Toxicity

As is the case with many plant proteins, lectins can be toxic to humans.

For example, uncooked kidney beans contain high levels of a type of lectin called phytohemagglutinin, which is toxic to humans and can cause digestive upset, nausea, vomiting, and diarrhea if ingested.

While this may sound concerning, note that toxic effects would only occur at larger doses than people typically consume.

Also, the lectin content in foods can be almost completely eliminated through cooking. The foods that contain high levels of toxic lectins are foods that are pretty much always cooked before consumption. For example, raw legumes like dried kidney beans and soybeans are usually soaked and boiled before eating, or they are sold pre-cooked, leaving little lectin content.

Digestion

As mentioned before, lectins are quite resistant to the acidity of the digestive tract and are difficult for humans to digest.

In particular, individuals with digestive sensitivities may have trouble digesting lectins, and respond poorly to lectins. Lectins may induce inflammation and worsen the symptoms of digestive disorders such as irritable bowel syndrome (IBS) (1).

These digestive issues are due to the ability of lectins to survive the digestive tract and bind to the lining of the gut, where they can damage the gut lining, disrupt the gut microbiome, interfere with metabolism, and interfere with nutrient absorption (2, 3).

Nutrient absorption

Lectins are sometimes called “anti-nutrients” because studies have shown that active lectins can interfere with the body’s absorption of important minerals such as calcium, iron, zinc, and phosphorous.

Note: there are many different types of lectins, and not all of them are going to have negative effects. Many lectins are harmless, and some can even be beneficial. Also, sensitivity and reactivity to lectins will differ between different people.

What is the Lectin-Free Diet?

The lectin-free diet is just as it sounds – a diet that excludes foods that contain lectin.

This diet is meant to eliminate lectin intake completely, or reduce lectin intake by ensuring high-lectin foods are cooked before eating in order to inactivate the lectins. (more on how to reduce lectin below)

The creator of the lectin-free diet, Dr. Steven Gundry, attributes lectin sensitivity to a range of health issues such as weight gain and leaky gut.

However, evidence remains limited. Whether or not lectin-foods are to be avoided is still a subject of much debate among nutrition experts.

Who is the lectin-free diet good for?

A lectin-free or low-lectin diet may be worth considering for individuals with digestive issues or food sensitivities.

On the other hand, individuals who do not have adverse reactions to consuming foods that contain lectins probably do not want to miss out on the nutrients that a lot of these foods are rich in.

Foods like veggies, legumes, and whole grains are important sources of dietary fibre, vitamins, and minerals. The benefits of eating these nutritious foods likely outweigh any potential benefits of cutting them out for the sake of avoiding lectins.

For this reason, individuals at risk of nutrient deficiencies, and individuals following plant-based diets, are probably not the best candidates for a lectin-free diet.

How to Reduce Lectin Content in Food

If you are worried about lectins, keep in mind that you don’t have to cut out lectin-rich foods from your diet entirely to avoid eating too many lectins. Remember that you can reduce the lectin content of lectin-rich foods by cooking them.

And even then, this shouldn’t be a big concern. High-lectin foods like beans or peas are often sold already soaked and cooked (in a can, for example). And if you buy them in their raw, dried form, you’ll have to soak and boil them before eating anyways.

In addition to soaking and cooking, sprouting or fermenting can also reduce lectin content of high-lectin foods (4).

Summary

Lectins are proteins found in many foods including legumes, nightshade vegetables, and whole grains. Lectins may be harmful to individuals with digestive sensitivities as they can disrupt digestion and impair nutrient absorption. More research is needed to fully understand the harmful or beneficial roles of lectins in the diet. Lectin intake can be reduced by cooking lectin-rich foods before eating them.

That’s it for this article on lectins. I’m curious, have you heard of the lectin-free diet before, or maybe given it a shot? Let me know in the comments below!