There is considerable research showing that nuts, with their high levels of unsaturated fatty acids, fiber and minerals, may help reduce the risk for cardiovascular disease. But a large Swedish analysis published in Heart has found that the benefits are limited and depend largely on other healthy behaviors.
Researchers followed 61,364 adults for up to 17 years. They had all completed questionnaires on diet, lifestyle and other risk factors for chronic disease.
Nut consumption was associated with lowered risk for heart attack, heart failure, stroke and the irregular rapid heartbeat called atrial fibrillation, or A-fib. But people who routinely consumed nuts were on average younger and more highly educated, had lower body mass index, were more likely to be physically active, less likely to smoke, and more likely to eat fruits and vegetables.
When the researchers controlled for these factors, nut consumption was associated only with a lower risk for A-fib, and had no significant effect on the other cardiovascular diseases.
“It’s possible that previous studies didn’t control for as many factors as we did,” said the lead author, Susanna C. Larsson, an associate professor of epidemiology at the Karolinska Institute. “Nuts are a good food, but they may not provide as much benefit as we once thought.”