Are Lectins Really Bad for You? Everything You Need to Know About Protein and Inflammation

Is the lectin-free diet one of the worst diets in history? Dr. Steven Gundry claims substances called lectins in our diet cause diseases — and that the way to avoid these diseases is to avoid these foods. Is there science behind his suggestions?

Here’s everything you need to know about lectins, which foods contain them, and whether or not you should worry about leaving them out of your diet.

What are lectins, and which foods have them?

Navy beans

Navy beans |

Lectins are proteins found in foods such as beans, vegetables, and some grains that the human body cannot digest. They exist in some amount in everything you eat, and are said to bind to carbohydrates when entering your body.

In large amounts, lectins have been shown to contribute to digestive issues such as diarrhea and vomiting in rats. The theory is that the non-digestable proteins “stick” to intestinal walls and increase the risk of damage and other issues.

However, there’s little evidence that shows the average person experiences digestive problems because of lectins. Continue reading to find out why.

Lectins and inflammation: Are they related?

Research conducted in animals has suggested that consuming large amounts of lectins can cause inflammation, which increases the risk of developing health conditions such as heart disease.

However, research conducted in humans suggests that consuming whole grains decreases the risk of inflammation and related diseases.

Furthermore, experts advise that foods that contain fiber — such as vegetables and beans — benefit digestive health.

The same way some people can be sensitive to gluten, it’s possible to have a sensitivity to lectins. But also keep in mind that digestive problems related to food have many potential causes. Plants are some of the best foods you can eat. Why go without?

The downsides of a lectin-free diet

Brown rice

Brown rice | vm2002/iStock/Getty Images

Eliminating foods that contain lectins doesn’t make sense when you realize they’re part of everything you’re eating. It’s also important to realize that humans don’t typically consume the amount of these foods required to cause problems. There’s a reason you can’t trust studies conducted on mice: they don’t eat like we do, especially in labs.

The “proof” lectins are bad for humans doesn’t technically exist. The research suggesting so-called lectin toxicity has largely been conducted on rats and other animals and insects. This is done to build the foundation for further research in people and does not technically prove that lectins are in any way harmful to humans.

The lectin content of foods decreases when you cook them. Cooking kidney beans, for example, decreases the number of lectins in them to a safe-to-consume level. Would you ever eat uncooked kidney beans? Hopefully not. Many foods high in lectins are meant to be cooked, and thus aren’t dangerous to the average person’s health.

The health benefits of these foods outweigh lectin dangers. When you focus on one nutrient in specific foods that might cause harm in large amounts, you risk denouncing the health benefits of these same foods. Vegetables, for example, contain essential vitamins and minerals such as fiber that many people don’t get enough of. Should you really avoid them simply because they contain lectins? Doing so unnecessarily could deprive you of the nutrition you need.

The lectin-free diet was developed by a doctor who sells a “lectin blocker.” This dietary supplement — a lectin “shield” — is said to block the effects of lectins and allow you to eat as many lectin-containing foods as you want. Don’t you find it suspicious that the guy who started warning people about lectins is the one manufacturing the “cure”?

If some foods that contain large amounts of lectins happen to bother your stomach, don’t eat them in large quantities — or at all. But don’t avoid foods that are good for you because you’ve heard they aren’t.

Until we know more about how these nutrients affect people, there’s no way to prove that avoiding high-lectin foods will benefit your health. Like all fads, the lectin-free diet can be dangerous if taken to the extreme.