One of the smartest and simplest things I ever did to improve my nutrition was to leave a bowl of nuts sitting on the kitchen counter. Not a day goes by that I don't grab a handful, thereby improving my lipid profile, increasing endothelial function, reducing inflammation, and possibly even making myself leaner.
By having the bowl in such a prominent place, I can't help but notice it and fortify my nutrition whenever I pass by. Miraculously, this particular bowl, like the wine pitcher in the Greek myth about Zeus and Hermes and the old couple that took them in, is never empty. Of course, it could just be my wife refilling it. I should ask.
Anyhow, I've lately grown tired of the taste of these "raw" nuts that, given their price, should come in a silk-lined jewelry case, embossed with the Whole Foods logo. I wondered if the cheaper, dry-roasted and salted kind matched up nutritionally. If they did, my taste buds and my wallet would be thankful.
It turns out the two type of nuts are – at least according to two studies – just as nutritious. Dry roasting most popular varieties of nuts does nothing to their polyphenol content or their cardio-protective effects in general. Dry roasting does, however, relieve "dietary monotony."
In one study, researchers asked 72 nut munchers to eat 30 grams per day of either raw or dry roasted, lightly salted hazelnuts (1). Blood pressure, HDL cholesterol, apolipoprotein A1, total cholesterol/HDL ratio, and systolic blood pressure all improved significantly in both groups. Both groups of nut eaters also lost a tiny bit of body fat (100 to 200 grams) and gained a tiny bit (100 grams) of muscle.
The only "bad" thing that roasting did to the nuts was to slightly diminish their alpha-tocopherol (at type of vitamin E) content.
Another study analyzed free and total polyphenol content in 9 types of roasted nuts. Roasting had little effect on either category of polyphenols (2).
Get thee some nuts and leave them out where they beg to be eaten. Taking some liberties with the Gaga-gian dictum, it doesn't matter if you love roasted, or capital R-A-W. Just put your paws out and grab some nuts.
The varieties that contain the most polyphenols (and presumably the most overall health benefits) are walnuts, hazelnuts, almonds, and pecans.
Note, though, that this recommendation doesn't include the greasy, canned nuts found in grocery stores and coveted by lazy hosts or hostesses who serve them at dinner parties. As Chris Shugart wrote in Nuts, You're Eating Them Wrong, "Typical snack nuts are cooked, or roasted, in cheap cottonseed oil, a highly processed vegetable oil brimming with omega-6 fatty acids."
The recommendation is to consume dry-roasted nuts, which are nuts that were prepared by applying heat without the use of oil or water as a carrier. While the oil-roasted nuts may still have the same polyphenol content as raw or dry-roasted nuts, they sure as hell aren't going to convey any cardio-protective effects.
- Tey SL et al. Do dry roasting, lightly salting nuts affect their cardioprotective properties and acceptability? Eur J Nutr. 2017 Apr;56(3):1025-1036.
- Vinson JA et al. Nuts, especially walnuts, have both antioxidant quantity and efficacy and exhibit significant potential health benefits. Food Funct. 2012 Feb;3(2):134-40. PubMed.