Nut consumption was verified at the start of the study, and then every two to four years during the study. During about 30 years of follow-up, more than 16,000 women and more than 11,000 men died.
When the researchers compared people who ate nuts to people who never ate nuts, they found a 7 percent reduced risk of dying from any cause during the 30-year study. People who consumed more nuts had an even lower risk of dying. Those who had nuts once a week had an 11 percent lower risk of death, while people who had two to four servings of nuts a week saw their risk drop by 13 percent. Those who consumed the most nuts -- at least seven 1-ounce servings weekly -- reduced their overall death risk by 20 percent, according to the study.
Eating more nuts also was linked to a lower risk of death due to cancer, heart disease and respiratory disease.
The study uncovered an association between eating nuts and living longer, but it didn't prove cause-and-effect.
Fuchs said a 1-ounce serving was equal to about 16 to 24 almonds, 16 to 18 cashews or 30 to 35 peanuts.
People who ate nuts tended to be healthier overall, according to the study. They were leaner, had lower rates of obesity, had lower cholesterol, had less high blood sugar, had smaller waist circumferences, ate more fruits and vegetables, and exercised more than people who ate fewer or no nuts.
Fuchs and his team controlled the data to account for these factors.
One expert said what people who are eating nuts aren't eating instead is also important.
"This study adds to the research that nuts are part of an overall healthful diet, especially if people are choosing to have nuts instead of chips or candy," said Alice Bender, associate director for nutrition programs with the American Institute for Cancer Research.
"Nuts provide quality protein, fiber, good fats [and] B vitamins," she said. "Nuts are a whole package of health, and they've shown some cancer-protective qualities."
"But nuts aren't a magic bullet," she said. "They're just one part of all the wonderful foods we have. It's important to eat foods that are minimally processed."
"The best thing to do is to substitute nuts for other foods that may be crunchy or sweet," Bender said. "Replace some of those foods that don't contribute much to our diets with nuts. You'll be replacing empty calories with a whole food."