Researchers looked at the diets of more than 200,000 people in both the United States and China, and found nut consumption was linked with a lower risk of premature death from heart disease and other causes.
The findings lend support to previous evidence on the heart-healthy benefits of nuts, said study researcher Dr. Xiao-Ou Shu, associate director of global health and professor of medicine at Vanderbilt University in Nashville, Tenn, WebMD reported.
However, Shu said, the finding is "based on an observational study," so the researchers cannot prove cause-and-effect with certainty. "That said, the totality of evidence from nutrition and health research suggests that nut and peanut consumption can be considered a healthy lifestyle choice," she said.
Shu's team asked men and women about their intake of nuts, including peanuts and peanut butter. Peanuts are often less expensive than other nuts, an important feature for the many low-income men and women who were studied, Shu said.
The group who ate the most nuts, peanuts and peanut butter reduced their risk of early death from heart disease and all other causes by about 20 percent, compared to the group eating the least, she said.
"Because peanuts [which do not grow on trees] are much less expensive than tree nuts, as well as more widely available to people of all races and all socioeconomic backgrounds, our study finding suggests that increasing peanut consumption may provide a potentially cost-efficient approach to improving cardiovascular health," Shu said.
How many peanuts should one eat, exactly? The US group in the top 20 percent of peanut consumption ate more than 18 grams a day, or about 0.63 ounces, roughly 2 tablespoons of shelled peanuts, Shu said.