SEATTLE, WASHINGTON. Cardiac arrest is a serious, usually fatal condition in which the heart stops pumping. Cardiac arrest most commonly occurs in connection with ventricular fibrillation and its primary cause is a heart attack. Researchers at the University of Washington now report that the risk of cardiac arrest can be significantly lowered by an increased intake of seafood rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Because fish and fish oils contain EPA and DHA, could there be a relationship between fish or fish oils and cardiac arrest prevention?
The researchers’ study involved 334 patients who had suffered cardiac arrest during the period 1988 to 1994 and 493 controls matched for age and sex. None of the study participants had had any indication of heart disease prior to the beginning of the study. Interviews with survivors or their spouses were used to determine the participant's fish intake in the month preceding the cardiac arrest. The researchers found that the intake of just one portion of fatty fish per week lowered the risk of cardiac arrest by an impressive 50 per cent after adjusting for age, smoking, family history of heart attacks, hypertension, diabetes, obesity, physical activity, education, and cholesterol level. Therefore, a relationship was found between consuming fish oils and cardiac arrest risk.
The researchers believe that consumption of fish increases the level of EPA and DHA in the membranes of the red blood cells which in turn reduces platelet aggregation and coronary spasm. This belief was confirmed by finding that blood samples taken from 95 cardiac arrest patients and 133 controls showed that a high blood content of EPA and DHA (five per cent of total fatty acids) corresponded to a 70 per cent reduction in the risk of cardiac arrest when compared to study participants with a low EPA and DHA content in their blood (3.3 per cent of total fatty acids). Other studies have shown that patients who have already suffered a heart attack can reduce their risk of future life-threatening arrhythmias and sudden cardiac death by increasing their intake of fish, fish oils or linolenic acid (flax seed oil). The researchers conclude that there may be a relationship between fish or fish oils and cardiac arrest in that a modest intake of EPA and DHA from seafood may reduce the risk of ventricular fibrillation and death from coronary heart disease.
Siscovick, David S., et al. Dietary intake and cell membrane levels of long-chain n-3 polyunsaturated fatty acids and the risk of primary cardiac arrest. Journal of the American Medical Association, Vol. 274, No. 17, November 1, 1995, pp. 1363-67