Lectins: What You Need To Know.

September 2, 2019

 If you are suffering from any chronic illness, and spent a lot of time searching for answers, you definitely have stumbled on information about lectins. Multiple publications claim lectins as a major cause for obesity, chronic inflammation, and autoimmune diseases, like arthritis.


Lectins are found in all plants, but raw legumes (beans, lentils, peas, soybeans, peanuts) and whole grains like wheat contain the highest amounts of lectins. Is there truth behind these claims?


The main reason for lectins in the plants is to defend them in nature from the insects, animals and some diseases. They are stable in acidic environments, resist being broken down in the gut  by digestive enzymes and can easily pass through into the stool unchanged.


Some types of lectins, such as ricin from castor beans, are very poisonous, and can be used as a possible warfare agent.[1] Others are less toxic, like phytohamagglutinin  from raw kidney beans, and can cause severe abdominal pain, vomiting, and diarrhea.[2]


Studies in animals and humans showed that they can interfere with the absorption of minerals, especially calcium, iron, phosphorus, and zinc.


Lectins can also bind to cells lining the digestive tract. This may disrupt the breakdown and absorption of nutrients, and affect the growth and action of intestinal flora.


Because lectin proteins bind to intestinal cells for long periods of time, they can cause an autoimmune response and play a role in inflammatory conditions like rheumatoid arthritis, diabetes, arteriosclerosis, depression, fatigue, brain fog". [3,4]


They spiked bacterial growth in the small intestine and stripped away the mucous defense layer. This increases the risk of IBS, peptic ulcers, increased intestinal permeability("leaky gut").[3]


So what food has the highest lectin content:


  •  All peas,

  •  All beans,

  •  Lentils,

  •  Peanuts, and peanuts based products, like peanut-butter, peanut oil,

  •  Soybeans; 

Nuts and seeds;

Corn, corn oil;


  • Tomatoes,

  • Potatoes,

  • Eggplant,

  • Squash,

  • Spices (such as peppermint and nutmeg),

  • Goji berries;


  • Wheat,

  • Barley,

  • Quinoa,

  • Rye;


Dairy products, like regular A1 milk, cheese, cottage cheese, yogurt, kefir;

Vegetable oils:

  • Sunflower oil,

  • Soybean oil,

  • Safflower oil, etc.


All plants and animal products contain some lectins. Dr. Steven Gundry is a cardio-thoracic surgeon, heart surgeon, medical researcher, who was one of the first doctors to point out the effects of lectin in his book, ''The Plant Paradox'', staying that lectins are "the hidden dangers in 'healthy' foods that cause disease and weight gain."[5]


He recommends consuming a wide but select variety of vegetables, wild-caught seafood, some nuts, fats, oils and A2 milk dairy products. Pasture-raised meats and poultry, and some fruits, are allowed in moderation.


Here is the list of Lectin-Free Foods:


Oils, Fats, and Nuts:

  • Algae oil, 

  • Olive oil,

  • Grass-fed ghee, 

  • Coconut oil,

  • Macadamia oil,

  • MCT oil,                               

  • Avocado oil,

  • Perilla oil,

  • Walnut oil,

  • Red palm oil,

  • Rice bran oil,

  • Sesame oil,                                 

  • Flavored cod liver oil

  • Macadamia, Walnuts, Pecans, Pistachios, Pine nuts, Brazil nuts;


  • Avocado,

  • Apples

  • All berries in season (berries are natural lectin blockers),

  • Kiwis,

  • Persimmon,

  • Green mango,

  • Green papaya;


Resistant Starches and Grains:

  •  Wraps made with coconut flour,

  • Green plantains,

  • Sweet potatoes, Yams,

  • Rutabaga,

  • Parsnips,

  • Yucca,

  • Celery root,

  • Glucomannan,

  • Jicama,

  • Taro roots,

  • Turnips,

  • Tiger nuts,

  • Millet, 

  • Sorghum,

  • Buckwheat;



  • Cruciferous (Broccoli, Brussels sprouts, Cauliflower, Bok choy, Napa cabbage, Chinese                               cabbage, Swiss chard, Arugula, Watercress, Collards, Kale),

  • Green and Red cabbage,

  • Radicchio, Nopales cactus,

  • Celery, Okra (lectin blocker), Asparagus,

  • Onions, Leeks, Chives, Scallions, Chicory ,Garlic,

  • Carrot, Carrot greens,

  • Artichokes, Beets, Radishes, Daikon radishes, Jerusalem artichokes, Hearts of palm,

  • Cilantro,

  • Leafy greens, Romaine, Red and green leaf lettuce, Kohlrabi, Mesclun, Spinach,

  • Endive, Dandelion greens, Butter lettuce, Fennel, Escarole, Mustard greens, Mizuna,

  • Parsley, Basil, Mint, Purslane, Perilla;


Algae, Seaweed , Sea vegetables (Bladder wrack is a lectin blocker);





You can still enjoy healthy food, that contain lectins, but need to reduce it concentration through the following techniques.



Sprouting is a process seeds, grains, beans, and other plant foods undergo when conditions are just right. The greater the sprouting duration, the lesser the concentration of lectins.

Sprouting may also ease the digestion process and unleash more valuable nutrients, including iron and vitamin C.



Soaking raw beans and grains is suggested to minimize lectin content. As a general rule of thumb, soak beans for at least two hours, or overnight if possible.

Adding baking soda and pressure-cooking can also lessen lectin concentration.



Cooking high-lectin foods can reduce or completely eliminate the lectin content. Lectins are reduced at a high temperature and if cooked long enough.



Fermentation is the process in which beneficial bacteria are able to reduce harmful substances in the body. Sauerkraut, yogurt, tempeh, and kombucha are well-known food sources that undergo the fermentation process. The fermentation process has shown to reduce lectin content up to 95 percent.


For more information on healthy eating please make an appointment with Dr. Koganski or our nutritionist Amy by calling 215-750-7000, or go online: https://NewtownInternalMedicine.com



1. https://emergency.cdc.gov/agent/ricin/facts.asp, accessed on 9/2/19

2. Vasconcelos IM, Oliveira JT. Antinutritional properties of plant lectins. Toxicon. 2004 Sep 15;44(4):385-403

3. Freed, DLJ. Do dietary lectins cause disease? The evidence is suggestive—and raises interesting possibilities for treatment. BMJ. 1999 Apr 17; 318(7190): 1023–1024

4. Vojdani A . Lectins, agglutinins, and their roles in autoimmune reactivities.   Altern Ther Health Med. 2015;21 Suppl 1:46-515. 

5. Gundry MD, Dr. Steven R. The Plant Paradox: The Hidden Dangers in "Healthy" Foods That Cause Disease and Weight Gain.


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