The Truth Behind Lectins
There has been significant discussion and curiosity around lectins and whether they are harmful or beneficial to our health, only to be met with a multitude of conflicting information about this protein and whether or not they should be incorporated or avoided in our everyday meals. Team DLW is here to give you a full breakdown of what exactly lectins are, their health benefits and potential drawbacks, and to help you understand when, how, and if you should consume or avoid them depending upon your specific health conditions, concerns and goals.
What Are Lectins?
Lectins are a broad group of proteins, often referred to as “anti-nutrients” that reversibly bind to carbohydrates by way of agglutination, meaning they bring molecules together into a clump. They are found in about 30% of foods, with the highest levels found in grains, nuts, seeds, legumes, fruits, and vegetables.
Currently research on lectins is evolving and still relatively limited. The biggest thing to note is that while lectins, in high concentrations, can potentially have a negative impact on the body for some people, it is important to note that lectins also have a wide variety of important nutritive properties.
Benefits of Lectins:
Lectins have immunomodulatory properties, meaning they activate our body’s innate immune response by signaling defense cells when they recognize a microbe (bacteria, virus, fungus) or foreign invader within the body. They can be effective at fighting certain types of undesirable bacteria, including the strain of bacteria that causes Staph infections and E.coli. Plant lectins are often present at the sites of microbial invasion and can bind to fungal structures, inhibiting their growth and proliferation.
Low to moderate amounts of lectins in the diet can lead to improved nutrient absorption and promotion of bacteria flora diversity.
Lectins may possess anti-cancer properties.
Foods that contain lectins are often also high in fiber, phytonutrients, antioxidants, minerals and vitamins.
Drawbacks of Lectins:
Lectins can cause nutrient deficiencies, disrupt digestion and cause intestinal damage when consumed in excess by individuals with impaired gut function.
Lectins can bind (agglutinate) to the GI mucosa, which can weaken it and make it more permeable.
Lectins can activate inflammatory responses and secrete inflammatory signaling molecules.
Lectins can lead to specific immune reactions that are associated with autoimmune disorders. Undigested lectins can also bind to various tissue cells and antigens, this binding can cause an immune attack against the lectins and the tissue to which the lectins are bound.
Highest Sources of Lectins
Lectins are found primarily in grains, dairy, legumes, nuts, seeds, fruits and vegetables. Lectins in grains, dairy and legumes are most commonly associated with aggravation of inflammatory and digestive diseases in the body.
Higher Lectin Foods
Grain-fed/non-organic dairy products, fish, meat and poultry
Grains: barley, bulger, quinoa, buckwheat, kamut, rye, spelt, wheat, oats
Legumes
Beans
Lentils
Oils: Canola, cottonseed, peanut, safflower, and sunflower seed
Nuts: Almonds, cashews, pine nuts, hazelnuts
Seeds: Sunflower, sesame
Melons, corn, cucumbers, eggplant, peppers, pumpkin, squash, tomatoes
Agave, sugar, artificial sweeteners
Lower Lectin Diets
Team DLW recommends following a low lectin diet only as a short-term plan for individuals with known autoimmune diseases, complex gut issues, or severe inflammation.
Low Lectin List
Fruits: Apples, berries (strawberries, blueberries, raspberries), cherries, kiwi, nectarines, pomegranate, peaches, coconut and citrus
Vegetables: Arugula, artichokes, asparagus, beets, broccoli, brussel sprouts, cabbage, carrots, cauliflower, celery, kale, leafy greens, leeks, mushrooms, okra, onions, radish, scallions, swiss chard
Animal Protein:Grass-fed dairy and meat products, wild caught seafood, organic eggs
Oils: Coconut, olive, avocado, macadamia, walnut
Nuts/Seeds: Macadamia, pecans, pistachios, walnuts, chestnuts, flaxseed, hemp, chia, pumpkin seeds
Grains: Amaranth, millet, wild rice
Reducing Lectins
Traditional cooking methods such as soaking, sprouting, pressure cooking and fermenting can reduce lectin contents within foods.
Boiling or cooking foods so that the foods containing lectins have exposure to heat and water for several minutes can reduce lectins.
Soaking grains, legumes and seeds can help reduce lectin content. The best way to do this is to submerge the food in water with 1 T. of apple cider vinegar or lemon juice and to allow the foods to soak for 4-24 hours. Soaking foods can make them more digestible and can also make the nutrients more bioavailable.
Sprouting grains, legumes and seeds on your own or purchasing pre-sprouted food items can help reduce lectin content.
Fermentation can also reduce lectins, as during the process of using bacteria or yeast to convert carbohydrates to alcohol or organic acids, the lectin proteins are actually consumed by bacteria.
*** NOTE: Dry heat such as grilling, air frying, baking and roasting can in some instances increase lectins.***
As with all topics related to nutrition both the pros and cons must be considered and there is not a universal approach that works for everyone. Low-lectin diets can be highly restrictive and difficult to follow as they reduce and eliminate many nutrient dense foods. Keeping this in consideration, a low lectin diet should only be followed if medically necessary and the diet should be monitored under the guidance of a nutrition or medical professional. In most instances, low lectin diets can be a short-term option for those with autoimmune diseases, complex gut issues, or severe inflammation. If you have more questions about lectins or are curious about a low lectin diet please reach out to Team DLW, we are here to support you!
References
Gong, T., Wang, X., Yang, Y., Yan, Y., Yu, C., Zhou, R., & Jiang, W. (2017, March 1). Plant lectins activate the NLRP3 inflammasome to promote inflammatory disorders. American Association of Immunologists. https://journals.aai.org/jimmunol/article/198/5/2082/102514/Plant-Lectins-Activate-the-NLRP3-Inflammasome-To
Hamid, R., & Masood, A. (2009). Dietary lectins as disease causing toxicants. Science Alert: Research Papers, Journals, Authors, Publishers. https://scialert.net/abstract/?doi=pjn.2009.293.303
Kilpatrik, D. C. (2002, July 11). Animal Lectins: A historical introduction and overview. Biochimica et Biophysica Acta (BBA) - General Subjects. https://www.sciencedirect.com/science/article/abs/pii/S0304416502003082?via%3Dihub
Lagarda-Diaz, I., Guzman-Partida, A. M., & Vazquez-Moreno, L. (2017, June 12). Legume lectins: Proteins with diverse applications. MDPI. https://www.mdpi.com/1422-0067/18/6/1242
Lipski, E. (2020). Digestive wellness: Strengthen the immune system and prevent disease through healthy digestion. McGraw-Hill.
Oppenheim, J. D., & Nachbar, M. S. (1979, July 1). Lectins in the United States Diet: A survey of lectins in commonly consumed foods and a review of the literature. The American Journal of Clinical Nutrition. https://www.sciencedirect.com/science/article/pii/S0002916523441202?via%3Dihub
Souza, M. A., Carvalho, F. C., Ruas, L. P., Ricci-Azevedo, R., & Roque-Barreira, M. C. (2013, January 9). The immunomodulatory effect of plant lectins: A review with emphasis on ARTINM Properties - Glycoconjugate Journal. SpringerLink. https://link.springer.com/article/10.1007/s10719-012-9464-4
Van Damme, E. J., Peumans, W. J., Pusztai, A., & Bardocz, S. (1998). Handbook of plant lectins: Properties and biomedical application. J. Willey & Sons.
Vojdani, A. (2015). Lectins, agglutinins, and their roles in autoimmune reactivities. Alternative therapies in health and medicine. https://pubmed.ncbi.nlm.nih.gov/25599185/