Recently, stories about the negative effects of lectins on health have led to an anti-lectin movement and new diet crazes like the lectin-free Plant Paradox Diet. Lectins are proteins that bind to carbohydrates. They are found in all plants, but raw legumes (like beans, grains, peanuts, soybeans, and peas) contain high amounts of lectins.

Lectins can have negative effects when consumed raw. Studies show that lectins protect plants from insects because the lectins cause perforations in the intestines, or “leaky gut” that allows bacteria and toxins into the body of the insects. Some studies have found a similar danger to people, particularly people with sensitive digestive systems. Popularly, excess lectins in the diet are associated with digestive and skin problems, as well as fatigue.

A type of lectin found in kidney beans causes red blood cells to clump together, with people getting ill from as few as five undercooked kidney beans. Active lectins can also reduce the absorption of minerals from a meal, mainly calcium, iron, phosphorus, and zinc.

Boiling, cooking, and removing the outsides are effective ways to eliminate most lectins. Cooked pasta, boiled beans, peeled cucumbers, and fermented tempeh are lectin-safe. Soymilk, tofu, brown rice, raw tomatoes, and peanuts in all forms are not. Additionally, the body may inactivate some lectins by producing enzymes during digestion.

Once cooked, there are benefits to consuming foods containing inactivated lectins, because they contain fiber, antioxidants, protein, and nutrients. There may even be some active lectins that fight cancer. Overall, the health benefits of including cooked lectin-containing foods outweigh the potential harm of lectins.