Many plants contain lectins or agglutinins in their seeds, early leaves, and roots. Agglutinins have the ability to aggregate themselves, meaning that lectins bind to carbs—in nature, lectins act as the plant’s homemade pesticide by binding to invaders. This mechanism also provides a way for plant cells to communicate with each another.
There are different types of lectins, each with its own effect:
- Legume lectins
- Cucurbitaceous lectins (found in the sap or juice of cucumbers, melons, and squashes)
- Prolamin (i.e., gluten and gliadin) Agglutinin or hemagglutinin
- GMO foods may contain higher levels of lectins since they are bred to be more pest-resistant and lectins are a natural pesticide.
Why are they a problem?
Lectins are resistant to human digestion—because they are extremely small and sticky, they attach themselves to our gut cells, causing leaky gut. They can then enter the bloodstream and bind to any organ, connective tissue, joint, or blood vessel by binding to its cell membrane. For example, one of the reasons that we can’t consume castor beans or raw kidney beans is because they contain lectins that attach to our red blood cells, which leads to the same kind of clumping that occurs when receiving the wrong blood type during a transfusion.
Lectins can affect function throughout the body. In the book Lectins by Nathan Sharon, lectins in the form of lima and kidney beans lead to “…depressed growth, pancreas enlargement, depressed insulin, and disruption of normal protein, fat, and carbohydrate intermediary metabolism.”
Lectins have also been associated with leptin resistance. Remember, leptin is the satiety hormone, so being leptin-resistant means you won’t receive the “I’m full!” signal in time, leading to weight gain and metabolic syndrome.
Can we neutralize lectins?
Soaking, fermenting, sprouting, and cooking may help deactivate lectins by removing their sticky coat. But since each plant is so different, when it comes to some lectin-containing foods—alfalfa sprouts, for example—processing may make the lectins more likely to be absorbed.
Soaking beans overnight might help. Make sure you change the water frequently and that you rinse the soaked beans well before using. Adding baking soda may also help further neutralize the lectins.
Cooking sometimes helps, but again, some lectins are just stronger than others. For instance, red kidney beans become more toxic when heated to 80 degrees Celsius. Dry heat doesn’t work very well to break down lectins, either so unfortunately there is no blanket answer.