Objective:
To examine the association of α-linolenic acid (ALA 18:3n-3), an essential n-3 fatty acid derived from plants and vegetable oils, with mortality, coronary heart disease, and stroke among older adults. Due to the low correlation between dietary and circulating ALA that may reflect differences in diet and metabolism, we evaluated plasma phospholipid ALA and dietary ALA separately.
Methods:
The study population included participants from the Cardiovascular Health Study, a community-based longitudinal cohort of adults aged 65 or older, free of prevalent coronary heart disease and stroke. A total of 2,709 participants comprised the plasma phospholipid analysis group and 4,214 participants comprised the dietary analysis group. Plasma phospholipid ALA, an objective measure of circulating levels of ALA over the past 4-8 weeks, was measured using stored samples from 1992-1993. Dietary fatty acid intake was ascertained using food frequency questionnaires administered in 1989 and 1996. ALA was expressed as percent of total fatty acids and percent of total dietary fat for the plasma phospholipid and dietary analyses, respectively. Cox regression was used to assess the associations of plasma phospholipid and dietary ALA with mortality, and incident coronary heart disease or stroke.
Results:
Dietary ALA and plasma phospholipid ALA were modestly correlated (r=0.18). We found no statistically significant associations of plasma phospholipid ALA with mortality, incident CHD or stroke (table). After adjustment for potential confounders, dietary intake of ALA was associated with a lower risk of total and non-CVD mortality. We found no statistically significant associations of dietary ALA with CVD mortality, incident CHD or stroke (table).
Conclusions:
Results from this prospective cohort study of older adults suggest that dietary, but not plasma phospholipid ALA, is associated with a lower risk of total and non-CVD mortality in older adults.
n−3 Polyunsaturated fatty acids, fatal ischemic heart disease, and nonfatal myocardial infarction in older adults: the Cardiovascular Health Study