Eating specific types of fats, such as polyunsaturated fats, may reduce the risk of premature death by 27%, according to the results of a new study from Harvard1. Walnuts are the only nut in which the fat is primarily polyunsaturated fat (13g/oz.), which includes a significant amount of alpha-linolenic acid (ALA (2.5g/oz.).
Researchers looked at the eating habits of more than 126,000 men and women over a 32-year period and found that if people replaced 5% of their calorie intake from saturated fats with equivalent calories from polyunsaturated fats they could potentially reduce the risk of premature death by 27%. If those calories came from monounsaturated fats, the risk of premature mortality was potentially reduced by 13%. Additionally, the findings suggest that consuming more saturated and trans fat may be associated with an increased risk of premature death.
As stated in the paper, although this study included a large sample size with high rates of participation, there are some limitations that should be considered. Other factors may have contributed to the findings, such as a change in eating habits during the course of the study or participating in other lifestyle factors common among adults that eat certain types of foods. This was an observational study in which subjects were not assigned to eat specific foods, and were simply asked about their dietary choices, so direct cause and effect cannot be established. It is also possible that subjects may have misreported their dietary intake since this information was collected by questionnaires.
Resources:
1Wang DD, Li Y, Chiuve SE, et al. Association of Specific Dietary Fats with Total and Cause-Specific Mortality. JAMA Intern Med. 2016;176(8):1134-1145. doi:10.1001/jamainternmed.2016.2417.