Of course, it's hard to know what came first: do nuts make us healthier, or do healthier people eat nuts? Certainly, nut eaters seem to be more likely to follow the fruits-and-vegetables Mediterranean diet, have their weight under control, are less likely to smoke and are physically more active.
Nut eaters reduce their chances of dying prematurely by 39 per cent, and those who eat walnuts reduce their risk by 45 per cent, compared to a non-nut eater. The reduction rose to 55 per cent in those who ate one serving of 28 g of nuts three times a week.
(Source: BMC Medicine, 2013; 11: 164).