Lectins

A while back, lectins made their way into the media. They were held responsible for practically every illness known to man, thanks to Steven Gundry’s book, The Plant Paradox. He claimed that lectins were responsible for disease and obesity.

​He was wrong. There is no scientific evidence to support his claims. But lectins can hurt you. Let’s learn the truth about lectins and how they impact the plants in your garden (and your body).

Toxic lectin found in fava beans (Thamelry) Public Domain

What are lectins?

Lectins are protein molecules that bind to specific carbohydrates. The word lectin comes to us from the Latin word for choose, which is a good description of what scientists believe lectins do inside your plants. While more research is needed, lectins appear critical to cell recognition. 

Plants use lectins to facilitate interactions between pollen and the stigma during pollination. They also play a role in maintaining seed hull integrity. When a plant cell bumps into harmful bacteria, beneficial microorganisms, or fellow plant cells, lectins initiate the proper response. That response can be anything from toxic warfare, a welcome mat, or cell-to-cell communication.

Tomato seeds contain lectins.

Legumes and members of the nightshade family have high concentrations of lectins in their seeds. Those concentrations decrease as plants germinate and grow.

Most beans contain lectins.

Lectins as toxins


The toxic warfare response may be what triggered Mr. Gundry's belief that lectins cause human disease. Lectins are toxic in specific situations. They are the reason why beans and other legumes are difficult for us to digest. That’s why we cook them. The heat breaks down the lectins (among other things).


Can lectins hurt me?

Some plants contain enough lectin to cause illness or even death. Castor oil beans are one example - but who wants to eat those? ​

Castor oil beans (Schnobby) CC BY-SA 3.0

Castor oil bean plant (Geographer) CC BY 1.0

In most cases, we typically can not eat enough lectin-containing plants to hurt us. As always, take sensational media with a grain of salt. And cook your beans.