Alpha-linolenic acid: is it essential to cardiovascular health?

Abstract

There is a large body of scientific evidence that has been confirmed in randomized controlled trials indicating a cardioprotective effect for omega-3 fatty acids from fish. For alpha-linolenic acid (ALA), which is the omega-3 fatty acid from plants, the relation to cardiovascular health is less clear. We reviewed the recent literature on dietary ALA intake, ALA tissue concentrations, and cardiovascular health in humans. Short-term trials (6-12 weeks) in generally healthy participants mostly showed no or inconsistent effects of ALA intake (1.2-3.6 g/d) on blood lipids, low-density lipoprotein oxidation, lipoprotein(a), and apolipoproteins A-I and B. Studies of ALA in relation to inflammatory markers and glucose metabolism yielded conflicting results. With regard to clinical cardiovascular outcomes, there is observational evidence for a protective effect against nonfatal myocardial infarction. However, no protective associations were observed between ALA status and risk of heart failure, atrial fibrillation, and sudden death. Findings from long-term trials of ALA supplementation are awaited to answer the question whether food-based or higher doses of ALA could be important for cardiovascular health in cardiac patients and the general population.

Fig. 1

Odds ratios and 95% confidence intervals for nonfatal myocardial infarction (MI) by deciles of alpha-linolenic acid in adipose tissue (a) or intake (b) in a case–control study of 3638 men and women in Costa Rica. Data were adjusted for smoking status, physical activity, household income, history of diabetes mellitus, history of hypertension, waist-to-hip ratio, saturated fat intake, and linoleic and trans fatty acids in adipose tissue. (From Campos et al. [••]; with permission)