Positive Health Online

Abstract

ASCHERIO, Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts 02115, USA, describes epidemiological studies on dietary fats and coronary heart disease.
The results of large prospective epidemiological studies support the hypothesis that the risk of coronary heart disease depends on the quality rather than on the quantity of dietary fat. Saturated fatty acids and cholesterol increase the risk of coronary heart disease as predicted by their well-established effects on blood lipids. Strong evidence has emerged that the deleterious effects of trans unsaturated fatty acids go beyond those predicted by their influence on the ratio of low-density lipoprotein to high-density lipoprotein cholesterol. Increased consumption of the polyunsaturated fatty acids linoleic and linolenic acid appears to reduce the risk of coronary heart disease.
Ascherio A. Epidemiological studies on dietary fats and coronary heart disease. The American Journal of Medicine 13 Suppl 9B: 9S-12S, Dec 30, 2002. LEMAITRE and colleagues, Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle 98101, USA, rozenl@u.washington.edu, have studied n-3 polyunsaturated fatty acids and myocardial infarction in older adults in the Cardiovascular Health Study.

Background

Little is known about the relation of dietary intake of n-3 polyunsaturated fatty acids, i.e. docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and alpha-linolenic acid, with ischaemic heart disease in older adults. This study aimed to investigate the association of plasma phospholipid concentrations of DHA, EPA, and alpha-linolenic acid with the risk of fatal ischaemic heart disease and nonfatal myocardial infarction in older adults.

Methodology

This was a case-controlled study nested in the Cardiovascular Health Study, a cohort study of adults aged 65 and over. 54 cases of fatal myocardial infarction and other fatal ischaemic heart disease, and 125 cases of nonfatal myocardial infarction were matched to 179 randomly selected controls. Plasma phospholipid concentrations of n-3 polyunsaturated fatty acids were measured in blood samples drawn approximately 2 years before the event.

Results

A higher concentration of combined DHA and EPA was associated with a lower risk of fatal ischaemic heart disease (odds ratio 0.32, p = 0.01). A tendency to lower risk, after adjustment for other risk factors, was observed for alpha-linolenic acid (odds ratio 0.52, p = 0.1). However n-3 polyunsaturated fatty acids were not associated with lower risk of nonfatal myocardial infarction.

Conclusion

Higher combined intake of DHA and EPA, and possibly alpha-linolenic acid, may lower the risk of fatal ischaemic heart disease in older adults. The association of these n-3 polyunsaturated fatty acids with fatal but not with nonfatal myocardial infarction is consistent with possible antiarrhythmic effects of these fatty acids.

References

Lemaitre RN, King IB, Mozaffarian D, Kuller LH, Tracy RP, Siscovick DS. n-3 Polyunsaturated fatty acids, fatal ischemic heart disease, and nonfatal myocardial infarction in older adults: the Cardiovascular Health Study. The American Journal of Clinical Nutrition 77 (2): 279-280, Feb 2003.

Comment

These are important results which again suggest important roles for essential fatty acids including DHA and EPA.