Ron, of Corvallis, Oregon, wrote this in response to a recent column on lectins: “I’m a biochemist and used to work with immunologists at Sloan Kettering. The main reason I’m writing is to ask you to explore the toxicity of the lectins of nuts and the best way to prepare nuts without getting sick. My wife loves pecans, I like cashews and pistachios best.
I’m interested in the chemistry and physiology of lectins, but I doubt most readers are. “
Well, Ron, it may be easier to talk about lectin chemistry than your main question. That’s because there is very little research into the lectin content of nuts – or whether they pose a problem at all.
A recent review article in the journal Nutrients states that lectins are widespread in the plant kingdom (more than 500 different species have been identified). When active, lectins can interfere with the absorption of nutrients and – according to animal experiments – even play a role in triggering digestive and other diseases.
On the other hand, certain lectins are now being examined for their therapeutic benefits, in particular for the diagnosis and treatment of cancer. And with it the paradox.
According to research by Blue Zones, lectins are found in all plants, a protein that helps them thrive and survive.
“The same properties that protect them in nature can lead to indigestion when consumed by humans – but there is a catch,” the research continues. “Lectins are found in ALL plants. Plants we’ve been eating for thousands of years, like rice, wheat, potatoes, tomatoes, seeds, nuts, but the highest amounts are found in raw legumes (beans, lentils, soybeans, peas, and Contain peanuts) and whole grain products …
Avoiding lectins entirely would mean avoiding almost all plant-based foods, which would mean avoiding the majority of the foods that the longest lived people in the world consume every day of their lives, as well as the foods that have been shown to increase the risk of chronic diseases such as heart disease decrease and diabetes. “
So Ron, while I couldn’t find any data on the exact levels of lectins in nuts, here’s the good news about your favorites. They are all heated, boiled or dried after harvest, which experts say can reduce or eliminate the activity of lectins.
Pecans are heated in a 180-degree Fahrenheit water bath as part of processing. Although pistachios can be eaten raw, most commercial pistachios are heat dried before packaging. And cashews are never sold raw. They need to be boiled, roasted, or steamed to remove a toxic oil in the peel that can irritate the skin like poison ivy.
At this point I would say that the evidence of the health effects of nuts far outweighs the threat from lectins, especially when we eat products that are toasted or otherwise cooked. Thanks for stretching my brain this week!