Lectins are one of the most important sources of food sensitivity, but they are often overlooked. If you suffer from persistent digestive issues or autoimmune flare-ups, you may want to consider whether lectins are a problem for you.
What are lectins?
Lectins are a diverse family of protein molecules that plants have evolved to defend against predators, including insects and animals. They are often called sticky proteins because they have the ability to bind to specific carbohydrate molecules.
Plant lectins generally cause cells to clump together, hence the name “agglutinin” (e.g., wheat germ agglutinin). When attached to sugar molecules, they affect cellular communication. Plant agglutinins have the ability to clump together blood cells of certain blood types, which may indicate that some people with certain blood types may be more susceptible to health problems due to lectins than others.
Lectins are concentrated in plant seeds and roots. There are a range of different types of lectins, with some causing more health problems than others. These include:
Legumes – like chickpeas, kidney beans, lentils
Cucurbits – found in melons and squash
Prolamins – cereals including wheat and gluten/gliadin
Agglutinin – soy, wheat germ
What’s the problem with lectins?
Some foods are naturally higher in lectins than others and some lectins are more toxic than others. They are commonly called “antinutrients” because they can reduce the digestibility and absorption of nutrients. Lectins are not easily digested or broken down by heat. This means they can enter the bloodstream, overactivate the immune system and disrupt hormones.
We know that one of the ways they affect health is in the gut. Lectins bind to cells in the intestinal lining, causing cell damage and intestinal permeability.
In particular, wheat germ has been shown to break the tight junctions of intestinal cells, allowing increased exposure of antigens to the immune system. When lectins enter the bloodstream, antibodies develop and inflammation is evident.
Lectins can induce mast cell reactions, suggesting that they may worsen allergies and histamine intolerance and increase sensitivity to other foods. A particular concern regarding lectins is their link to autoimmune diseases. In sensitive individuals, lectins can trigger or worsen existing autoimmune diseases. As they increase inflammatory chemicals like TNF alpha and IL1, they can overstimulate the immune response, worsening some autoimmune diseases like rheumatoid arthritis.
They also appear to alter the gut microbiome, which can in turn increase gut inflammation and intestinal permeability.
Another area of concern is the role that certain types of lectins like wheat germ may have on insulin health and potentially trigger insulin resistance.
Are you sensitive?
Our sensitivity to lectins varies greatly. This can be influenced by our gut health, our microbiome, our immune system, our underlying genetic predisposition and our age (younger people are generally more resilient). It’s also possible that if you already have gut symptoms, an autoimmune disease, or have eaten large amounts of lectin foods (e.g., vegan diet), you might be more sensitive. Additionally, if you have been under a lot of stress or have previously had chronic immune activation, such as an infection, you may be more susceptible.
The low lectin diet
Commonly implicated foods include legumes (including soy, unfermented soy), wheat and other gluten-containing grains, the nightshade family (potato, tomato, chili, pepper, eggplant), and certain nuts such as cashew nuts.
But the good news is that there are a wide range of low-lectin foods you can enjoy. Interestingly, fermenting certain foods like soy (e.g. natto and tempeh) can make certain foods easier to digest. Additionally, long cooking times and pressure cooking of certain foods help reduce lectins. Additionally, as many lectins are found in the skins and seeds, by peeling and/or deseeding certain fruits you can also reduce the levels. So there are benefits to soaking and slow cooking beans and lentils, which is actually the traditional way of preparing these foods. This may also explain why, for some people, good fermented sourdough bread is easier to digest.
Navigating low-lectin foods can seem overwhelming at first, which is one of the reasons I created a Lean Low-Lectin Meal and Nutrition Plan and Nourish Club.
Key foods to avoid include grains, beans and legumes, certain nuts and seeds, the nightshade family, and some dairy products. It’s a good idea to make sure you’re getting enough healthy starches and fiber to support a healthy gut microbiome, as well as anti-inflammatory fats like olive oil, avocado, omega 3 fats, MCT oil, black cumin seed oil, and some seed/nut oils. like macadamia nut oil. One group of vegetables to include regularly are cruciferous vegetables as they are packed with nutrients and antioxidants. Although eggs are incredibly nutritious and safe on a low-lectin diet, they are a common allergen, so keep in mind that they may not be suitable for everyone.
There is no magic lab test to identify if lectins or certain lectin-containing foods are causing a problem for you. The easiest way is to avoid lectins for 2 to 4 weeks and monitor your symptoms to see if they are a problem for you. You can access my low lectin meal plan by being a member of our Lean and Nourish group.