Q: What can you tell me about the possible toxic effect of peanut oil lectin (PNA)? Ive read where the Paleo Diet cites research showing that PNA from peanuts and peanut oil clogs the arteries.


Answer :We tracked down one of the original researchers in those 1998 studies, David Klurfeld, PhD, who is now a national program leader in human nutrition with the USDAs Agricultural Research Service. He replies:

A little background is in order to understand why we did those studies many years ago. Rabbits and monkeys fed peanut oil had more cardiovascular lesions than expected from a polyunsaturated oil-almost as much as from the most saturated fats. I developed a method that extracted lectin from vegetable oils and we found lectin in all refined oils at extremely low levels. Peanut lectin is a protein that binds to a carbohydrate on endothelial cells, which line blood vessels. And this lectin differs from lectins found in other seed oils. So it was plausible that lectin explained some or all of the unexpected effects on lesion formation.

Since then, epidemiological and, more important, intervention studies with peanuts and many types of tree nuts have shown not only no increase in serum cholesterol or risk of heart disease but a reduced risk. So there is, in my opinion, no harm from consumption of peanuts or peanut oil. This story has developed a life of its own and has been perpetuated on the Internet along with similar fables.


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