By Michael Greger MD

INCREASED NUT consumption has been associated with a reduced risk of major chronic diseases, such as heart disease and diabetes. But do those who eat nuts actually live longer lives? Clinical trials have shown nuts help lower cholesterol and oxidation, and improve our arterial function and blood sugar levels. Does all this translate into greater longevity?

Researchers at Harvard examined the association between nut consumption and subsequent mortality of over 100,000 people followed for decades. In that time, tens of thousands died, but those that ate nuts every day lived significantly longer. Daily nut consumers had fewer deaths from cancer, heart disease, and respiratory disease, even after controlling for other lifestyle factors. Nut consumers lived significantly longer whether they were older or younger, fat or skinny, whether they exercised more, smoked, drank, or ate other foods that may affect mortality.

But nuts are so filled with fat that there “may be a concern that frequent nut consumption can result in weight gain.” However, that’s not what the Harvard researchers found. In fact, other studies have associated nut consumption with a slimmer waist, less weight gain, and lower risk of obesity. If we look at all the studies put together, it’s pretty much a wash. Diets enriched with nuts do not seem to affect body weight, body mass index, or waist circumference much at all. For example, one of the most recent such studies, in which subjects were told to add either 0, 70, or 120 pistachios to their daily diet as an afternoon snack every day for three months, found no noticeable difference between the three groups. You couldn’t see any difference between those eating no nuts and those eating more than 100 a day. Hence, it appears that the incorporation of nuts (around one to two small handfuls a day) would be advisable to ensure various health benefits without the risk of body weight gain.

How nuts do we have to go? Not much. Just a few servings a week may boost our lifespan and lower cancer rates—but it appears we have to keep it up. In the PREDIMED study, when long-time nut eaters were told to cut down on eating nuts or choose extra virgin olive oil, within five years they apparently lost much of their longevity benefit. Only the group that started out eating nuts and continued to eat at least the same amount of nuts died significantly less often.