The study, published in the journal Nutrients and funded by the California Walnut Commission, found eating five or more servings of walnuts per week was associated with a 14% lower risk of death (from any cause), 25% lower risk of dying from cardiovascular diseases, and a gain in about 1.3 years of life expectancy, compared to those who didn’t consume walnuts.

For the study, researchers examined data from 67,014 women of the Nurses’ Health Study who were average aged 63.6 years and 26,326 men from the Health Professionals Follow-up Study aged 63.3 years in 1986. Participants were relatively healthy when they joined the studies (e.g., free of cancer, heart disease and stroke) and were followed for about 20 years (1998-2018). Dietary intake was assessed every four years in which participants reported on their overall dietary intake—including how often they consumed walnuts, other tree nuts and peanuts—as well as lifestyle factors like exercise and smoking status. Based on the data, researchers identified associations between walnut consumption at varying levels and different health indicators related to longevity.

One ounce of walnuts is a powerhouse of important nutrients, including 4 g protein, 2 g fiber, 45 mg of magnesium (45mg) and 2.5 g of essential omega-3 ALA.

While eating five or more servings of walnuts a day had the most benefits, the researchers noted consuming walnuts in lower amounts also had benefits. Eating walnuts two to four times per week had a 13% lower risk of death overall, 14% lower risk of dying from cardiovascular diseases, and a gain in about one year of life, compared to non-walnut consumers. Even among people with a suboptimal diet, consuming just a one-half serving of walnuts per day was associated with benefits, including 12% reduced risk of death and 26% lower risk of death from cardiovascular diseases.

“What we’ve learned from this study is that even a few handfuls of walnuts per week may help promote longevity, especially among those whose diet quality isn’t great to begin with. It’s a practical tip that can be feasible for a number of people who are looking to improve their health, which is top of mind for many people,” said Yanping Li, senior research scientist at the Department of Nutrition at Harvard T.H. Chan School of Public Health, and lead investigator of this research.