Key Findings:
Experimental studies have suggested an antiarrhythmic effect of alpha-linolenic acid which may be due to an increased electrical threshold for induction of ventricular fibrillation Here a stronger effect of ALA in reducing IHD was found among vitamin E supplement users, suggesting that the availability of antioxidants such as vitamin E may be important for the biologic effect of ALA. This study provides support for the hypothesis that a higher intake of ALA will reduce the risk of fatal IHD.
ABSTRACT:
Background: Experimental studies in laboratory animals and humans suggest that a-linolenic acid (18:3n23) may reduce the risk of arrhythmia. Objective: The objective was to examine the association between dietary intake of a-linolenic acid and risk of fatal ischemic heart disease (IHD). Design: This was a prospective cohort study. The intake of a-linolenic acid was derived from a 116-item food-frequency questionnaire completed in 1984 by 76 283 women without previously diagnosed cancer or cardiovascular disease. Results: During 10 y of follow-up, we documented 232 cases of fatal IHD and 597 cases of nonfatal myocardial infarction. After adjustment for age, standard coronary risk factors, and dietary intake of linoleic acid and other nutrients, a higher intake of alpha linolenic acid was associated with a lower relative risk (RR) of fatal IHD; the RRs from the lowest to highest quintiles were 1.0, 0.99, 0.90, 0.67, and 0.55 (95% CI: 0.32, 0.94; P for trend = 0.01). For nonfatal myocardial infarction there was only a modest, nonsignificant trend toward a reduced risk when extreme quintiles were compared (RR: 0.85; 95% CI: 0.61, 1.19; P for trend = 0.50). A higher intake of oil and vinegar salad dressing, an important source of alpha-linolenic acid, was associated with reduced risk of fatal IHD when women who consumed this food 5–6 times/wk were compared with those who rarely consumed this food (RR: 0.46; 95% CI: 0.27, 0.76; P for trend = 0.001). Conclusions: This study supports the hypothesis that a higher intake of alpha-linolenic acid is protective against fatal IHD. Higher consumption of foods such as oil-based salad dressing that provide polyunsaturated fats, including alpha-linolenic acid, may reduce the risk of fatal IHD.