Lectins: What Foods Contain them?

And What to Do About It

By Nancy Mehlert, MS

If you are reading this without first reading our main article, you may want to back up and read it to benefit from the more in depth introduction to lectins.

Now, for anyone struggling to lose weight, dealing with autoimmunity or digestive issues, or simply frustrated with a stubborn health problem, then it is worth considering that lectins may be holding back your journey to better health.

Lectins are found in a wide variety of foods making it impossible to eat a lectin free diet. Not all lectins are bad (see Tip #5 below), however there are many lectins that are quite harmful, and there are some foods that contain high levels. It is important to think about the cumulative impact since you may be eating a combination of high lectin foods that result in considerable toxicity.

Foods with the Highest Lectin Content – Best Avoided:

Corn – One of the very highest in lectin foods, corn lectins are also very resistant to heat and, therefore, are difficult to reduce through cooking. Pervasive in the American food supply, corn is also genetically modified (unless organic) and one of the highest allergenic foods.
Corn-fed Meats: This includes most meats sold in grocery stores and restaurants. We are what we eat, and this applies to animals, too. They are raised on corn and soy, two foods that are high in lectins. The purpose is to make them fat for market. Lectins make us humans fat, too. The best way to avoid them is to buy certified grassfed meat. The American Grassfed Association is a good place to learn more. Look for “100% Grass Fed and Finished” on the label.
Casein A1 Milk[1]: Because of a genetic mutation in cow populations, some cows produce milk containing casein A1 protein, which is a lectin-like protein called beta-casomorphin. It attaches to the pancreas’ insulin-producing cells, prompting an immune attack on the pancreas of those who consume milk and cheeses from these cows. Most cows today are casein A1 producers, and this is the milk and cheese found in store-bought dairy. Many who believe they are lactose intolerant are responding to the casein A1 in the milk. If you are going to consume dairy, opt for only casein A2 dairy products which come from goat, sheep, water buffaloes or specifically Belgian Blues, Guernsey, or Brown Swiss cow breeds. Holsteins are the most common breed and their milk is casein A1. Jersey cows may produce either, so checking the source and verifying is critical.
Peanuts and Cashews: Commonly called nuts, peanuts and cashews are legumes and both are very high in lectin content. The shell around the cashew is such an irritant that cashew workers must wear protective gloves to harvest them. Cashews are in the same botanical family as poison ivy and dramatically increase inflammation[2].
Unfermented Soybean Products: Examples include tofu and edamame, the green soybean where lectins are highest and best avoided. Traditionally fermented soy products such as miso or tempeh, if organic, have a much lower lectin content due to the fermentation.

High Lectin Foods to Eat Sparingly and Prepare Properly:

Legumes: This pulse family includes any plant seed that is found in pods, such as peas, green beans, lentils, split peas, and all other beans (e.g. red kidney, black, white, garbanzo). Proper soaking and cooking, as well as choosing some of the lower lectin options like Great Northern beans, green beans and lentils, can make these a reasonable option when used sparingly. Most canned beans have not been soaked or cooked properly to reduce lectins. White kidney beans and soybeans are highest in lectins.
Grains: Just when we thought whole grains were best for us, we are learning that the lectins are highest in the outer sheath. Most earlier cultures seemed to understand that removing it made digestion easier. Traditionally, the Chinese, Japanese, and other Asian people have not been plagued with obesity, heart disease, and diabetes, yet they have been eating rice for thousands of years, always stripping away the hull where the lectins exist[3]. WGA or gliadin attached to gluten in wheat, oats, rye and barley are two other damaging grain lectins. Is it any surprise that many traditional European breads are made using the process of fermentation to make sourdough bread? The process of fermentation deactivates lectins. This traditional process is not used in bread manufacturing by the food industry. There are many other health concerns when it comes to grains, such as pesticides and genetic modification. Careful selection, preparation, and minimal consumption, however, make some grains a viable choice from time to time.
Nightshade Fruits and Vegetables: Included are tomatoes, potatoes (excluding sweet potatoes), eggplants, bell peppers, and goji berries among others. The highest lectin content is found in the skins and seeds, so simply peeling and deseeding can significantly reduce the lectin content, as well as reducing frequency and portion. Potato lectins are quite resistant to cooking and will only reduce by 50-60%.
Gourd Family Fruits: Normally called vegetables, the gourd family are fruits and include all squash varieties, pumpkin and zucchini. As with nightshades, some of these can be peeled and deseeded well and cooking will also help reduce lectins.

Preparation and Cooking Tips to Reduce Lectin Content:

Research demonstrates that sprouting, fermenting, soaking overnight and cooking high lectin foods does dramatically reduce the lectin content, making them safe for most people. In addition to removing seeds and peel, here are some other tips to help reduce lectins.

Tip #1 – If you choose to eat beans, be sure to prepare and cook them properly, and NEVER eat raw or undercooked. They can have acute and toxic effects[4]. Be sure to soak beans in water for at least 12 hours before cooking, changing the water frequently. Rinse the beans well, discarding the water used for soaking. Cook for at least 15 minutes on HIGH heat, ideally using a pressure cooker like the InstaPot™.
Tip #2 – If consuming grains, keep in mind that the only way to make bread safe is to buy organic AND raise the bread using traditional methods of yeast or sourdough, which breaks down the gluten and other harmful lectins. You would be hard pressed to find this in our grocery stores. You will need to make it yourself or purchase it from a traditional artisan bakery.
Tip #3 – Many beans, seeds and grains can be sprouted to deactivate lectins. There are some exceptions, such as alfalfa, where sprouting increases lectins. We recommend the cookbook, Nourishing Traditions, by Sally Fallon for all forms of traditional food preparation including sprouting, fermentation, and cooking methods that reduce harmful lectins.
Tip #4 – Consider investing in a pressure cooker. Plant lectins are most effectively neutralized when cooked under pressure relatively quickly. This method is ideal for beans, legumes, quinoa and rice, for example. Avoid slow cookers for plant foods, as they will increase lectin content because of the low temperature used.
Tip #5 -There are some safe lectins in many foods. The lowest lectin content options are asparagus, garlic, celery, mushrooms and onions. Cooked root vegetables like sweet potatoes, yucca and taro, along with leafy greens, cruciferous vegetables, avocados, olives and olive oil are all examples of healthy foods that do contain some lectins. They can be eaten without restrictions.

Remember, while lectins can wreak havoc on health, it is not possible nor ideal to eliminate them from your diet. The key is to identify the worst culprits, cut those out, and make sure you are preparing food in ways that minimize or reduce lectin content. How strict you need to be will be determined by your health status, genetics and willingness to explore the possibility that lectins are standing in your way of better health.

ASK ABOUT OUR LECTIN SENSITIVITY TESTING. FIND OUT IF YOU REACT TO SOME SPECIFIC LECTINS!

[1] Gundry, Steven R., The Plant Paradox, (New York: HarperCollins, 2017), pg.32

[2] Gundry, Steven R., The Plant Paradox, (New York: HarperCollins, 2017), pg.209-210

[3] Gundry, Steven R., The Plant Paradox, (New York: HarperCollins, 2017), pg.45

[4] https://articles.mercola.com/sites/articles/archive/2017/08/14/reduce-lectins-in-your-diet.aspx

What are Lectins? Should I care?

By Mila McManus MD

The study of lectins is an extensive and emerging area of science with far-reaching implications to both health and healing. Learning about them may be a significant game changer for your health. The findings may even surprise you. It is quite possible that lectins are the hidden cause behind many symptoms and diseases. If you struggle to lose weight, have autoimmune disease, digestive issues, or have stubborn health problems that just don’t seem to improve or resolve, learning more about lectins may be time well spent.

Lectins are a large class of proteins that can be found in all forms of life. In plants, lectins are the natural defense system that protect the plant from destruction by microorganisms, pests, and insects[1]. Lectins make the plant leaves unappetizing, poisonous to invaders, or signal by color to the animal when a fruit is ready to eat. For example, during the growing process, a fruit will be green and high in lectins, therefore harmful and toxic to an invader. Later, the fruit will reach ripeness, turning a bright color, signaling to animals that the fruit is ready to be eaten. At ripeness, the lectin content has dropped and is no longer toxic to the predator. When the animal eats the fruit, it carries the seeds in the digestive tract to another area, and then defecates the seeds into a new place to grow, thus perpetuating the plant species. Lectins are in the seed’s outer coating as well as inside the seed on what will become the leaves once the seed sprouts.

Lectins are often referred to as “sticky proteins” because they are attracted to cell surfaces, causing cells to clump together (called agglutination). One extreme example is ricin, a lectin found in castor beans. It is such a potent lectin that just a minuscule amount ingested can cause death due to massive clotting of red blood cells from agglutination[2]. Another more familiar lectin is gliadin (a.k.a. wheat germ agglutinin or WGA). WGA is a component of gluten, the most well-known lectin of our time. Again, think of the “sticky” nature of lectins. Lectins bind to cells in the gut, blood, nerves, muscles, and joints, just to name a few. There, they act as chemical messengers, but their message is harmful, not helpful. It is a message to inflame and a message to wreak havoc. WGA is involved in almost every acute and chronic inflammatory disorder including neurodegenerative disease, inflammatory bowel disease, infections and autoimmune diseases².

Not all lectins are harmful, and some are even beneficial. Our focus today is on the lectins which inflict damage to the human body in the following ways:

Lectins from the diet damage the delicate intestinal lining, increasing gut permeability and compromising protein digestion[3].
Lectins can be transported across the intestinal membrane into general circulation where they may attach to other tissues (connective, nervous, bladder) causing immune dysfunction and systemic inflammation³.
Lectins are chemical messengers potent enough to initiate and aggravate existing inflammatory conditions including autoimmune diseases (e.g. thyroiditis, lupus, rheumatoid arthritis, fibromyalgia) ³.
Lectins have a significant impact on metabolism and weight gain. Normally, insulin acts like a delivery truck for excess carbohydrates (glucose) by attaching itself to the insulin receptor site (think loading dock) found on fat cells. Here, insulin tells the fat cell to open the storage room door, so that glucose can be moved into the fat cell for storage. Once the glucose has been stored as fat, the insulin backs away from the loading dock receptor site, and the fat cell locks up the door to the storage room. In many people, lectins disrupt this process in a significant way. Remember, the lectins are sticky. Lectins stick to the insulin receptor site (the loading dock) on the fat cell, mimics insulin by instructing the fat cell to open the storage room door and move glucose into storage as fat. However, lectins do not back away but instead stay indefinitely attached (stuck) to the receptor site giving a constant message to store fat².

Lectins do present a paradox. On one hand, plants are essential for good health and small amounts of lectins can be handled and managed by a healthy body. On the other hand, the wrong plants, eaten routinely and abundantly, can result in a cumulative toxic impact to the body over time. The same plant toxins that can kill or immobilize an insect can also silently destroy your health and insidiously impact your weight. Your current health status, family history, and genetic individuality will determine your body’s ability to recognize lectins as friends or foe.

We now have access to a lab test for lectin sensitivity for those who want to see results in writing before launching into a lectin reduction diet. Our supplement of the month is another helpful resource, as it works to block lectins from the gut surface and passage through it.

To find out more, read today’s Nutrition Nugget . There, we will address which high lectin foods are most damaging and best avoided, and which lectin foods can be prepared in ways that reduce the lectin content. For a more in-depth study of lectins, you may want to read The Plant Paradox, by Dr. Steven R. Gundry, MD., where you will also be introduced to his Plant Paradox Program diet.

[1] Peumans WJ, Van Damme EJ. Lectins as plant defense proteins. Plant Physiology. 1995;109(2):347-352

[2] Pierini, Carolyn M. Lectins: Their Damaging Role in Intestinal Health, Rheumatoid Arthritis and Weight Loss. Vitamin Research News. 2007;21(1):1-4

[3] Pierini, Carolyn M. Lectin Lock™:Natural Defense Against a Hidden Cause of Digestive Concerns and Weight Gain. Vitamin Research News.2007;21(2):6