BOSTON — Grab a handful of pecans, pistachios or peanuts. Munch on almonds or walnuts. Doing so potentially may lead to a longer life. Researchers from the Harvard School of Public Health and Brigham and Women’s Hospital University, both in Boston, found a significant, dose-dependent inverse association between nut consumption and total mortality in a study in the Nov. 21 issue of The New England Journal of Medicine.
Final analysis included 76,464 women in the Nurses’ Health Study and 42,498 men in the Health Professionals Follow-up Study. People who ate nuts seven or more times per week had a 20% lower death rate when compared with people who did not eat nuts. Inverse associations were observed for most major causes of death, including heart disease, cancer and respiratory diseases.
The study pointed out nuts contain nutrients such as unsaturated fatty acids, protein, fiber, vitamins, minerals and phytochemicals that may confer cardio-protective, anti-carcinogenic, anti-inflammatory and antioxidant properties.
The Food and Drug Administration in 2003 said scientific evidence suggests but does not prove that eating 1.5 oz per day of most nuts, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. Types of nuts eligible for the F.D.A. qualified health claim are restricted to almonds, hazelnuts, peanuts, pecans, some pine nuts, pistachio nuts and walnuts.
The study appearing in The New England Journal of Medicine received funding through grants from the National Institutes of Health, Bethesda, Md., and the International Tree Nut Council Nutrition Research & Educational Foundation, Davis, Calif. Funders had no role in the design or conduct of the study nor did they have any roles in the collection, management, analysis or interpretation of the data or in the preparation, review or approval of the manuscript.
Researchers defined baseline as the year of the first validated food-frequency questionnaire in each study, which was 1980 for the Nurses’ Health Study and 1986 for the Health Professionals Follow-up Study. In 1980 and 1984 questionnaires, people were asked how often they had consumed a serving of nuts (28 grams or 1 oz) during the preceding year. They could answer never or almost never, one to three times a month, once a week, two to four times a week, five or six times a week, once a day, two to three times a day, four to six times a day, or more than six times a day.
In subsequent questionnaires the questions were split into two items: peanuts and other nuts. Total nut consumption was defined as the intake of peanuts and other nuts even though peanuts technically are legumes.
The researchers documented 16,200 deaths during 30 years of follow-up in the Nurses’ Health Study. They documented 11,229 deaths during 24 years of follow-up in the Health Professionals Follow-up Study. Age-adjusted and multivariate-adjusted analyses showed a significant inverse association between frequency of nut consumption and total mortality among both women and men.
Pooled multivariate hazard ratios for death for people who ate nuts as compared to those who did not eat nuts were 0.93 for eating nuts less than once per week, 0.89 for once per week, 0.87 for two to four times per week, 0.85 for five or six times per week, and 0.80 for seven or more times per week.People who consumed nuts more frequently were leaner, less likely to smoke, more likely to exercise and more likely to use multivitamin supplements. They also ate more fruits and vegetables and drank more alcohol.