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Lectins: What They Are and What They Really Mean for Your Health

Plants, like all living things, have developed ways to protect themselves in the environment. One of those natural protective tools is a group of proteins called lectins. Lectins are found throughout the plant kingdom and have very specific biological functions. They are simply proteins that bind to certain carbohydrates, which is why the name “lectin” comes from the Latin word meaning “to select.”

Lectins were first identified in 1888 in castor beans because of their ability to bind to sugars on the surface of red blood cells. This property made them useful in laboratory testing, including blood typing. However, this laboratory use does not mean that lectins cause blood cells to clump inside the body when we eat plant foods. That idea is a misunderstanding of how lectins behave outside the body versus inside a functioning digestive system.

Lectins are naturally present in many common foods, including grains, beans, lentils, vegetables and fruits. In fact, nearly all plant foods contain some lectins. What matters is not their presence, but how the food is prepared and how the body handles them.

Some lectins, especially those found in raw or undercooked beans, can irritate the digestive tract and cause symptoms like bloating, cramping or diarrhea. A well-known example is phytohemagglutinin (PHA), found in raw or undercooked kidney beans. When eaten raw, these beans can cause significant digestive distress.

However, this is the key point that is often left out:

Cooking destroys lectins.

Soaking and properly cooking beans, lentils, grains and other starches inactivates the lectins that can cause discomfort. This is why beans and whole grains have been staple foods in cultures around the world for thousands of years and why populations that eat large amounts of these foods consistently show lower rates of heart disease, diabetes, obesity and many cancers.

When beans and grains are prepared in the traditional way — soaked and cooked — they are not dangerous. They are some of the most nutritious, satisfying and health-promoting foods on the planet.

In fact, the very foods that contain lectins are also rich in fiber, resistant starch, antioxidants and phytochemicals that improve gut health, lower cholesterol, stabilize blood sugar and reduce inflammation.

So while lectins can sound alarming when taken out of context, in real-world eating they are not something to fear. They are simply one of many naturally occurring plant compounds that are rendered harmless through normal cooking and digestion.

The bottom line is simple:

Whole, cooked plant foods — especially beans, lentils, whole grains, potatoes, vegetables and fruit — are safe, nourishing and central to a healthy starch-based diet.

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