November 20th, 2013
Consumption of Nuts Linked to Mortality Benefit
Nut consumption has long been linked to healthy lifestyles. Now, a study in the New England Journal of Medicine extends the finding and demonstrates a strong association with improved mortality.
Ying Bao and colleagues examined data from nearly 120,000 people enrolled in the Nurses’ Health Study and the Health Professionals Follow-up Study to assess the relationship of nut consumption and mortality. With over 3 million person-years of follow-up, the investigators found a strong inverse correlation between the frequency of nut consumption and mortality, after adjusting for other risk factors.
Here are the hazards ratio for death based on frequency of nut consumption (compared to no consumption):
- Less than once per week: 0.93 (CI 0.90-0.96)
- Once per week: 0.89 (CI 0.86-0.93)
- 2-4 times per week: 0.87 (CI 0.83-0.90)
- 5-6 times per week: 0.85 (CI 0.79-0.91)
- 7 or more times per week: 0.80 (CI 0.73-0.86)
Similar results were observed in both men and women separately. As well, there were significant reductions in deaths due to cancer and heart disease. The results were also similar when the investigators looked separately at the role of peanuts (a legume) and tree nuts.
Although nuts are often thought to cause weight gain, the investigators reported that increased nut consumption was associated with less weight gain in their study.
The authors acknowledged that as it was an observational study, they were not able to demonstrate a cause and effect relationship between nut consumption and mortality. However, they wrote, “our data are consistent with a wealth of existing observational and clinical-trial data in supporting the health benefits of nut consumption for many chronic diseases.” The ingredients in nuts “may confer cardioprotective, anti-carcinogenic, anti-inflammatory, and antioxidant properties.”
Recommended viewing: A NEJM animation, with narration by editor Jeffrey Drazen, explaining the study and its implications.