People who eat a diet rich in nuts, including peanuts, are less likely to die from heart disease or cancer, new research suggests.
The more nuts consumed, the greater the apparent benefit, according to the report. It included data from nurses and other health professionals who have been tracked since the 1980s.
Heart disease and cancer - the biggest killers in the U.S. - are responsible for more than one million annual deaths nationwide.
The International Tree Nut Council Nutrition Research and Education Foundation helped pay for the new report, which was published in the New England Journal of Medicine.
The findings dovetail with other research suggesting regularly eating nuts may lower the risk of common health problems such as heart disease, colon cancer and type 2 diabetes.
"Nuts used to be demonized because they're high in fat. Now, 20 years later, they're recognized as a healthful food," Jeffrey Blumberg told Reuters Health.
He is from the USDA Human Nutrition Research Center on Aging at Tufts University in Boston and wasn't part of the study team.
"It's just like coffee and eggs used to be demonized," Blumberg said. "Eggs used to be a heart attack in a shell. Nuts are high in fat, but they're high in good fats."
The new study - the largest to look at deaths - suggests the health benefits of nuts may translate to a lower risk of premature death, researchers said.
The variety of nut, including peanuts, which are actually legumes, did not seem to make a difference, senior author Dr. Charles Fuchs told Reuters Health.
"The benefit really seems to span across nuts," Fuchs, from the Dana-Farber Cancer Institute in Boston, said.
The two databases used in the analysis included about 76,000 women who are part of the ongoing Nurses' Health Study and 42,000 men who are regularly evaluated as part of the Health Professionals Follow-up Study. The findings are based on questionnaires in which the volunteers periodically recalled their eating habits.
The researchers had to account for the fact that nut eaters tended to be healthier when it came to smoking, alcohol consumption, obesity, exercise habits and other elements of their diet, such as eating more fruits and vegetables.
Yet even when those factors were taken into account, they said, nut consumption seemed to be tied to a lower risk of early death.
During 30 years of the Nurses' Health Study, about 16,000 women died. About 11,000 men died over a 24-year period in the Health Professionals Follow-up Study.
Compared to people who never ate nuts, those who ate nuts once a week were 11 percent less likely to die during the studies and those who ate nuts every day were 20 percent less likely to die.
People who reported eating nuts at least five times per week were 29 percent less likely to die of heart disease, in particular, than those who avoided nuts. They were also 24 percent less likely to die of respiratory conditions like chronic obstructive pulmonary disease and 11 percent less likely to die of cancer.
Nuts were not linked to fewer deaths from stroke, neurodegenerative disease, infection or kidney disease. Nor were they tied to a lower risk of dying from diabetes, even though some research has suggested nuts may have a benefit in that disease.
Fuchs said his personal recommendation is that people eat an ounce of nuts each day, although smaller amounts still seem to make a difference.
The study also suggests people who eat a lot of nuts are less likely to put on weight.
It's possible that people who like nuts tend to have a thinner body type, "but even after adjusting for lifestyle choices, we definitely see that people who eat nuts tend to be thinner and are less likely to be obese," Fuchs said.
It's not clear whether salted or spiced nuts are less beneficial than raw ones, the researchers noted.
Fuchs and his colleagues also cautioned that the study can't prove nuts were responsible for the lower risk of death. "However," they said, "our data are consistent with a wealth of existing observational and clinical-trial data in supporting the health benefits of nut consumption for many chronic diseases."