What are lectins?
Lectins are a group of proteins that have the ability to bind to certain kinds of carbohydrates. Most foods contain some lectins, which plants have been found to use for a variety of functions including protection and communication with their environments.
Certain foods, including legumes, most grains, and vegetables from the nightshade family, contain particularly high amounts of lectins. These are the foods that are avoided on a low lectin diet.
What’s the problem with lectins?
Lectins, in high quantities over long periods of time or for those who are sensitive, may lead to or worsen systemic inflammation and autoimmunity, disrupt digestion, and interfere with the absorption of nutrients (1, 2, 3).
Lectins, which cannot be digested and which bind to receptor sites along the intestinal wall, may damage the lining of the gut. They may also lead to an overgrowth of bacteria in the small intestine (SIBO), and/or dysbiosis (an imbalance of gut bacteria).
Lectins have been found to stimulate the immune system and have been closely linked to autoimmune diseases (4, 5). Lectins act as inflammatory agents, and research on individuals with autoimmune conditions has shown that following a low lectin diet can reduce markers of systemic inflammation (6).
An interesting mouse study found that the consumption of lectins together with a non-lectin protein led to a stronger immune system response to the non-lectin protein than if the non-lectin protein was eaten alone (7, 8). This suggests that eating high lectin foods along with low lectin foods may lead to or increase food sensitivities in general, and not just sensitivities to high lectin foods.
Who might benefit from the low lectin diet?
The low lectin diet is not for everyone. Although some proponents of the diet may argue that avoiding these proteins is beneficial for all of us, the effects of lectins on the body vary significantly based on our individual sensitivities, genetic makeup, and other factors.
Because it eliminates a number of foods that are generally considered healthy (including many plant foods and common sources of beneficial dietary fiber), the low lectin diet is not usually recommended as a first step for anyone.
However, if you have been following a clean, healthy, whole-foods diet and are still suffering, sensitivity to lectins may be the missing piece of the puzzle.
With that in mind, the low lectin diet may be helpful for those with Chronic Fatigue Syndrome, fibromyalgia, IBS and/or SIBO, and many autoimmune diseases, as well as for those who are suffering from chronic inflammation or brain fog, or who are having difficulty losing weight in spite of a healthy diet and lifestyle.
The idea is that if we remove lectins, which are acting as inflammatory agents and putting stress on the immune system and the digestive system, from the diet, the body can focus more of its energy and resources on healing and restoration.
Which foods should be avoided on the low lectin diet?
The low lectin diet involves reducing overall lectin intake by eliminating foods with a high lectin content, and taking steps to reduce the lectin content in other foods.
Many high lectin foods are plant foods that are staples in a generally healthy, well-rounded diet. For this reason, a low lectin diet should be explored only when a healthy diet rich in whole foods is already being followed and symptoms are persisting.
High lectin foods to avoid include:
-Plants from the nightshade family (including tomatoes, potatoes, eggplant, peppers)
-Legumes (including lentils, beans, chickpeas, soybeans, peanuts, and cashews)
-Squash, zucchini, and other vegetables from the gourd family
-Dairy products (which contain casein, a lectin-like protein)
-Corn (including products made with corn)
Low lectin diet tips
Legumes are particularly high in lectins, however, there are a number of ways to lower their lectin content without having to forego them altogether. Properly soaking beans before cooking is the first step, and pressure cooking will also reduce the lectin content of beans and legumes. Try an Instant Pot! Note that slow cooking will actually have the opposite effect.
Sprouting and fermentation will also help to reduce the lectin content of legumes, grains, and nightshades.
In order to ensure adequate nutrition while following a low lectin diet, make sure to eat lots of low lectin fruits and vegetables. Good vegetable choices on a low lectin diet include cucumbers, celery, romaine lettuce, and cruciferous vegetables.
A trial-and-error or elimination diet approach to this diet may be best, as many individuals with sensitivities to lectins are particularly sensitive to certain foods, and may be able to better tolerate others.
For more personalized guidance, request a consultation with Dr. John Gannage, MD.