I’ve promised a few people I’d write this up, so here it is.
I keep hearing that peanuts are healthy. When pressed, I’m usually referred to epidemiological evidence, but the evidence I”m referred to always looks at nuts in general, and not peanuts in particular. Considering their mono-unsaturated and poly-unsaturated fat content, it’s not a surprise the nuts are associated with a decreased risk of CHD — it’s been epidemiologically established that increasing the ratio of poly-unsaturated to saturated fat intake decreases heart disease (but increases cancer) mortality. There’s something strange about peanuts, though: peanut oil is atherogenic in rats, rabbits, and primates.
Randomizing peanut oil reduces its atherogenic properties (Tso P., Pinkston G., Klurfeld D.M., Kritchevsky D. (1984) Lipids 19, 11-16), but the randomization process does a lot of things (Kritchevsky D., Tepper S.A., Klurfeld D.M. (1998) Lipids 33, 821-823), so it’s hard to say what the actual cause is; maybe it’s just the lectin content. I’m skeptical of animal studies where a clear mechanism can’t be identified, but animal studies are stronger than nothing, which is all the support there is for the oft-repeated claim that peanuts are healthy. It’s not all that uncommon for results on primate studies to carry over to humans, and I prefer cashews to peanuts, almond butter to peanut butter, and hazelnut oil to peanut oil anyway, so these results were enough to get me to change my diet.