Foods containing lectins are commonly found in many people's diets. These naturally occurring proteins are found in most plants — with beans, peanuts, lentils, tomatoes, potatoes, eggplant, wheat and other grains containing higher amounts, according to the Mayo Clinic.
Lectins work to protect plants as they grow. If consumed raw, lectins have the potential to negatively impact your health.
However, the Mayo Clinic adds that most typical diets do not contain the levels of lectins you'd need to consume in order to cause concern. When cooked and not eaten raw, foods containing lectins actually have numerous health benefits.
Read more: The Best Foods for Gastric Problems
How Lectins Are Removed
If you're concerned about lectin toxicity or lectins and inflammation, make sure you have all the facts before eliminating lectins from your diet. Always check with your doctor to find the healthiest, most balanced diet for your needs.
It's rare to consume foods with a high amount of active lectins, explains Harvard T.H. Chan School of Public Health. Most foods containing lectins are not eaten raw, when lectins are the most potent.
For example, dried beans, such as kidney beans, are typically soaked and then boiled for hours before consumption, thus inactivating most lectins. Lectins, which are water-soluble, are mostly found on the exterior of a food — and removed when they come in contact with water.
Certain other processes work to remove lectins, too. The Harvard Chan School says the body can produce enzymes during digestion that degrade some lectins. Sprouting grains or beans or mechanically removing the outer hull of beans and wheat grains can also remove lectins.
Benefits of Lectins
The 2015-2020 Dietary Guidelines for Americans recommends eating a variety of fruits, vegetables and whole grains — i.e., foods that may contain lectins. Mayo Clinic notes that the benefits gained from including these foods in your diet outweigh any perceived benefits of avoiding foods containing lectins.
Indeed, lectins may help to stabilize blood sugar by slowing down digestion and the absorption of carbohydrates. Lectin-containing foods like legumes, whole grains and nuts may help to control weight and cut the risk of cardiovascular disease and Type 2 diabetes.
These foods also provide a rich source of B vitamins, protein, fiber, minerals and healthy fats. Furthermore, lectins can act as antioxidants that protect cells from free radicals, says the Harvard Chan School.
Lectins are also being studied in anticancer treatments, according to an August 2013 study published in the journal Cell Proliferation. There's some evidence that lectins may cause cancer cell death. Research published in July 2017 in the International Journal of Molecular Sciences concurs that lectins show potential as both diagnostic and treatment tools in digestive system cancers.
About Lectin Toxicity
June 2019 research published in the World Journal of Gastroenterology acknowledges there may be a link between lectins and inflammation. For example, lectins found in red kidney beans may cause gastrointestinal problems if not cooked properly.
According to the researchers, lectins are resistant to heat and must be cooked above 100 degrees Celsius for at least 30 minutes to inactivate them. That means cooking red kidney beans in a slow cooker might not get the heat high enough to deactivate lectins. At the same time, they acknowledge that more research is needed on lectins and inflammation to understand lectins' role in health and disease.
Nevertheless, some people with gastrointestinal problems may choose to eliminate foods containing lectin from their diet. For some people, it's possible that eating lectins and other antinutrients — compounds that block the absorption of certain nutrients — may irritate underlying digestive issue like irritable bowel syndrome, says the Harvard Chan School.
If you're concerned about lectin toxicity, use the following list of foods with lectins to help guide your dietary choices:
- Legumes, such as beans, chickpeas, lentils, peanuts
- Peanut-based foods like peanut butter
- Seeds and nuts
- Whole grains, including barley, quinoa, corn, rice, wheat and wheat germ
- Products made with grains or flours, such as crackers, breads and cakes
- Other packaged or processed foods that may contain lectins
- Many dairy products, such as milk
- Nightshade vegetables, such as eggplant, goji berries, peppers, tomatoes and potatoes
- Sweet peppers
- Citrus fruits
- Various other fruits, including pomegranate, grapes, cherries, quinces, apples, watermelon, banana, papaya, plums and currants
Be aware that if you're experiencing digestive distress, there can be a variety of causes. Although lectin toxicity or sensitivity is one possible explanation, you may also have a food allergy or intolerance — or another gastrointestinal issue.
Work with your doctor or a registered dietician to determine the root cause before deciding to eliminate lectin from your diet — or any food group or ingredient, for that matter.
- Mayo Clinic: "Mayo Clinic Q and A: What Are Dietary Lectins and Should You Avoid Eating Them?"
- Harvard T.H. Chan School of Public Health: The Nutrition Source: "Lectins"
- Harvard T.H. Chan School of Public Health: The Nutrition Source: "Are Anti-Nutrients Harmful?"
- Health.gov: "Dietary Guidelines for Americans, 2015-2020: Chapter 1. Key Elements of Healthy Eating Patterns"
- Cell Proliferation: "Could Plant Lectins Become Promising Anti‐Tumour Drugs for Causing Autophagic Cell Death?"
- World Journal of Gastroenterology: "Dietary Lectin Exclusion: The Next Big Food Trend?"
- International Journal of Molecular Sciences: "Plant Lectins as Medical Tools Against Digestive System Cancers"