Lectins — A Little Known Trouble Maker
While most of the world seems to be touting the benefits of whole grains these days, a few people are insisting that grains are not as healthy as we think.
One of the reasons grains may be a problem in human nutrition is because they contain lectins, a class of molecules called glycoproteins (molecules that contain a protein and a sugar).
While dietary lectins are known in the scientific and nutritional communities, most lay people and even many medical professionals don’t know about them.
Lectins are involved in food allergies/sensitivities, inflammation and autoimmune disease, just to name a few. For instance, lectins are linked to celiac disease. Even weight gain and low energy can be linked to lectins.
Whole grains, peanuts, kidney beans, and soybeans are high in lectins. Cow’s milk, nightshade vegetables (like potatoes and tomatoes) and some seafood also contain fairly high amounts of lectin. In fact, estimates are that about 30% of our foods contain lectins, and about 5% of the lectins we eat will enter our circulation.
Lectins are problematic because they are sticky molecules that can bind to the linings of human tissue, especially intestinal cells. In so doing, they disable cells in the GI tract, keeping them from repairing and rebuilding.1 Therefore, lectins can contribute to eroding your intestinal barrier (leaky gut).
Because the lectins also circulate throughout the bloodstream they can bind to any tissue in the body — thyroid, pancreas, collagen in joints, etc.2 This binding can disrupt the function of that tissue and cause white blood cells to attack the lectin-bound tissue, destroying it. This is an autoimmune response. The lectins in wheat for example, are specifically known to be involved in rheumatoid arthritis.
But why do only some people react to the lectins in foods while others can eat them with no apparent problems? There are two answers to this question. First, many people may be having problems but they just don’t realize it. For example, autoimmune thyroiditis could be caused by dietary lectins.6
As another example, many of our patients who thought they had no food intolerance at all have experienced much improved energy and weight control when they eliminated wheat and dairy. They didn’t realize until after they eliminated these foods that they were being affected by them.
But certainly many people tolerate these foods — why?
The answer lies in the balance of gut flora and a person’s immune system. When you have adequate beneficial flora, it serves as a protective barrier against substances that travel through the intestines, including lectins. But importantly, beneficial flora are needed to keep the production going in the intestines of two lectin-protective substances, mucin and secretory IgA.3,4
Mucin, like lectin, is a glycoprotein in the mucous lining of the intestines. When lectins travel through the intestines, they should have mucin to bind to, rather than intestinal cells. But if mucin is missing, lectins will bind to intestinal cells instead. Secretory IgA also binds to lectins, preventing them from causing damage.5
If you have any lectin-related health issues like arthritis, allergies or autoimmune disease, our experience shows it is very helpful to reduce your intake of lectins, especially from wheat. It’s also very important to balance immunity by working on stress management and gut health.
By taking a good quality probiotic you’ll help stimulate adequate mucin and secretory IgA production.3,4 And controlling your stress response will help prevent the over production of IgA and maintain immune balance in the gut to improve your tolerance to lectins.
- Pierini C. Vitamin Research News. Jan 2007. 21(1): 1-4.
- Eur J Clin Nutr. 1993 Oct;47(10):691-9.
- Deplancke B and Rex-Gaskins H. AJCN. June 2001. 73(6):1131S-1141S.
- Buts JP, et al. Digestive Disease and Sciences. Feb 1990. 35(2): 251-56.
- Cordain L et al. British Journal of Nutrition (2000), 83, 207–217.