AALBORG, DENMARK. Sudden cardiac death is the most common cause of death in Western countries and accounts for about 50% of all deaths from heart disease. In other words, 50% of all people with heart disease have their condition “diagnosed” by suddenly dying from it. It is clear that anything that might help to prevent sudden cardiac death (SCD) would be of immense benefit. Several clinical trials have concluded that eating fish regularly or supplementing with fish oils can reduce the risk of SCD by as much as 50%. Other studies have found that wine drinking also has a protective effect.
Danish researchers now report that fish oils markedly increase heart rate variability and conclude that this is probably the explanation for their protective effect. Their study involved 291 patients who had been referred for coronary angiography because of suspected heart disease. The participants completed food questionnaires including a question about wine consumption and had their blood cell (granulocytes) and fat tissue level of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) determined. The participants also had their heart rate variability (HRV) measured over a 24-hour period.
The researchers found an excellent correlation between the reported intake of fish and fat tissue levels of EPA and DHA. They also noted a distinct association between high EPA/DHA levels and high HRV. Patients with a high wine intake also had high HRV values, but further analysis showed that these patients also had a high fish intake. When corrected for this confounding variable there was no correlation between wine consumption and HRV. There also was no correlation between the intake of beer and HRV.
The researchers conclude that high body levels of EPA and DHA can markedly reduce the risk of sudden cardiac death and ascribe this protective effect to the increased heart rate variability associated with increased fish or fish oil consumption.
Christensen, Jeppe Hagstrup, et al. Marine n-3 fatty acids, wine intake, and heart rate variability in patients referred for coronary angiography. Circulation, Vol. 103, February 6, 2001, pp. 651-57
Bigger, J. Thomas and El-Sherif, Tarek. Polyunsaturated fatty acids and cardiovascular events: a fish tale. Circulation, Vol. 103, February 6, 2001, pp. 623-25 (editorial)