Lectin-free diet: Benefits, risks, and foods to eat and avoid
Lectins are proteins in plants that have been associated with both positive and negative health effects.
Some plant-based foods, such as beans and legumes, whole grains, and certain vegetables contain a high amount of lectins.
Read on to learn more about lectins and the lectin-free diet. What does science have to say about this diet? Why do some people recommend it, and does the evidence support their claims?
What are lectins?
Undercooked red kidney beans may cause severe nausea, diarrhea, and vomiting due to a lectin called phytohaemagglutinin.
Lectins are a type of protein that, in humans, may help cells interact with one another. Some scientists also believe that lectins provide a form of defense in plants to keep insects away.
These proteins also contain nitrogen, which is needed for plants to grow. While many parts of plants contain lectins, the seed is the part that people eat most often.
Lectins may impact health in multiple ways, ranging from digestion to chronic disease risk. They have been shown to cause red blood cells to cluster together.
They are categorized as antinutrients since they block the absorption of some nutrients.
Lectins may cause an upset stomach when plant foods are eaten uncooked. They are also the reason why it can be dangerous to eat undercooked legumes.
The lectin in red kidney beans is called phytohaemagglutinin. It is responsible for red kidney bean poisoning, which results from eating raw or undercooked kidney beans. According to the United States Food and Drug Administration (FDA), consuming just four raw kidney beans could cause symptoms including severe nausea, vomiting, and diarrhea.
Cooking methods that use moist heat are helpful for decreasing the number of lectins in plants. Cooking also breaks down some plant starch into simpler carbohydrates. Lectins like to attach to carbohydrates and are removed from the body before they cause negative effects.
Slow cookers are not recommended for preparing kidney beans because the temperature is not high enough to eliminate lectins. Ways to decrease lectins in foods include:
While lectins have some undesirable effects, they also have some positive ones. Small amounts of lectins may help the good bacteria that live in human digestive systems.
Research suggests that lectins may be useful for helping to identify and diagnose cancer. Lectins are also being studied for their potential to slow down the rate that cancer cells multiply.
Researchers are even looking at lectins as potential treatments for illnesses caused by bacteria, fungi, and viruses.
What is the lectin-free diet?
Dr. Steven Gundry popularized the lectin-free diet. He is a former heart surgeon who switched his focus to food and supplement-based medicine.
Dr. Gundry describes lectins as the main danger found in the American diet. In response, he has written a book that provides information on how to avoid lectins, alternative food choices, and recipes.
According to the book, Dr. Gundry’s plan helps people improve their health and reduce their body weight. The plan also includes supplements Dr. Gundry developed that are sold under the GundryMD brand.
Alongside many other foods, Dr Gundry recommends eating sweet potatoes to limit the intake of lectins.
Some scientists believe lectins are harmful and cause inflammation. An older article links them to autoimmune diseases, including celiac disease, diabetes, and rheumatoid arthritis.