People who regularly eat nuts appear to live longer, according to the largest study of its kind.
The findings, published in the New England Journal of Medicine, suggested the greatest benefit was in those munching on a daily portion.
The US team said nut eaters were likely to also have healthy lifestyles, but the nuts themselves were also contributing to their longer lifespan.
The British Heart Foundation said more research was needed to prove the link
The study followed nearly 120,000 people for 30 years. The more regularly people consumed nuts, the less likely they were to die during the study.
People eating nuts once a week were 11% less likely to have died during the study than those who never ate nuts.
Up to four portions was linked to a 13% reduction in deaths and a daily handful of nuts cut the death rate during the study by 20%.
Lead researcher Dr Charles Fuchs, from the Dana-Farber Cancer Institute and Brigham and Women's Hospital, said: "The most obvious benefit was a reduction of 29% in deaths from heart disease, but we also saw a significant reduction - 11% - in the risk of dying from cancer."
Eating nuts was linked to a healthier lifestyle - including being less likely to smoke or be overweight and more likely to exercise.
This was accounted for during the study, for example to eliminate the impact of smoking on cancer rates.
The researchers acknowledge that this process could not completely account for all of the differences between those regularly eating nuts and those not.
However, they said it was "unlikely" to change the results.
They suggest nuts are lowering cholesterol, inflammation and insulin resistance.
Victoria Taylor, senior dietician at the British Heart Foundation, said: "This study shows an association between regularly eating a small handful of nuts and a lower risk of death from coronary heart disease.
"While this is an interesting link, we need further research to confirm if it's the nuts that protect heart health, or other aspects of people's lifestyle.
"Nuts contain unsaturated fats, protein and a range of vitamins and minerals and make a good swap for snacks like chocolate bars, cakes and biscuits.
"Choosing plain, unsalted options rather than honeyed, salted, dry-roasted or chocolate-covered will keep your salt and sugar intake down."
The study was funded by the US National Institutes of Health and the International Tree Nut Council Nutrition Research & Education Foundation.