New Harvard study explores link between walnut consumption and life expectancy
A study has been published that higher walnut consumption may be associated with a lower risk of death and an increase in life expectancy among older adults in the U.S., compared to those who do not consume walnuts.
Done by researchers from the Harvard T.H. Chan School of Public Health, the study has been supported by the California Walnut Commission.
"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," 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.
"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," Li said.
This study found five or more one-ounce servings of walnuts per week may provide the greatest benefit for mortality risk and life expectancy.
Eating five or more servings per week was associated with a 14% lower risk of death (from any cause), a 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.
Consuming walnuts two to four times per week could have its benefits, too, with the study finding 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.
Participants were relatively healthy when they joined the studies and were followed for about 20 years (1998-2018).
Dietary intake was assessed every 4 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 this data, the researchers were able to identify associations between walnut consumption at varying levels and different health indicators related to longevity.
As a prospective observational study, these results do not prove cause and effect, but they do shed light on how walnuts may support an overall healthy lifestyle that promotes longevity.
Participants who consumed greater amounts of walnuts tended to be more physically active, have a healthier diet, lower alcohol consumption, and take multivitamins.
All of these factors could influence life expectancy, however, the researchers adjusted for these aspects in their analysis. In addition, it's important to note that this data was collected before the current Covid-19 pandemic.
One ounce of walnuts is a powerhouse of important nutrients for optimum health, including protein (4g), fiber (2g), a good source of magnesium (45mg) and an excellent source of the essential omega-3 ALA (2.5g).