Scientists from Dana-Farber Cancer Institute, Brigham and Women's Hospital, and the Harvard School of Public Health also found that regular nut-eaters are more slender than those who didn't eat nuts. The study also looked at the protective effect on specific causes of death. (Agencies)
"The most obvious benefit was a reduction of 29 percent in deaths from heart disease - the major killer of people in America," said Charles S Fuchs, director of the Gastrointestinal Cancer Center at Dana-Farber, who is the senior author of the report.
"But we also saw a significant reduction, 11 per cent, in the risk of dying from cancer," added Fuchs, who is also affiliated with the Channing Division of Network Medicine at Brigham and Women's.
Whether any specific type or types of nuts were crucial to the protective effect couldn't be determined.
However, the reduction in mortality was similar both for peanuts and for "tree nuts" - walnuts, hazelnuts, almonds, Brazil nuts, cashews, macadamias, pecans, cashews, pistachios and pine nuts.
Several previous studies have found an association between increasing nut consumption and a lower risk of diseases such as heart disease, type 2 diabetes, colon cancer, gallstones, and diverticulitis.
However, no previous study had looked in such detail at various levels of nut consumption and their effects on overall mortality in a large population that was followed for over 30 years.
For the new research, the scientists were able to tap databases from two well-known ongoing observational studies that collect data on diet and other lifestyle factors and various health outcomes.
The Nurses' Health Study provided data on 76,464 women between 1980 and 2010, and the Health Professionals' Follow-up Study yielded data on 42,498 men from 1986 to 2010.
Participants in the studies filled out detailed food questionnaires every two to four years. With each food questionnaire, participants were asked to estimate how often they consumed nuts in a serving size of one ounce.
"In all these analyses, the more nuts people ate, the less likely they were to die over the 30-year follow-up period," explained Ying Bao of Brigham and Women's Hospital, first author of the report.
Those who ate nuts less than once a week had a seven per cent reduction in mortality; once a week, 11 per cent reduction; two to four times per week, 13 per cent reduction; five to six times per week, 15 per cent reduction, and seven or more times a week, a 20 per cent reduction in death rate.
The report was published in the New England Journal of Medicine.
Scientists from Dana-Farber Cancer Institute, Brigham and Women's Hospital, and the Harvard School of Public Health also found that regular nut-eaters are more slender than those who didn't eat nuts. The study also looked at the protective effect on specific causes of death.