Positive Health Online

Abstract

MORI and colleagues, Department of Medicine, University of Western Australia, and the West Australian Heart Research Institute, Perth, Australia tmori@cyllene.uwa.edu.au studied the effects of purified eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) upon ambulatory blood pressure (BP) and heart rate (HR) in humans.

Background

Methodology

The authors conducted a double-blind, placebo-controlled trial. 59 overweight, mildly hyperlipidaemic men were randomised to 4 g/d of purified EPA, DHA or olive oil (placebo) capsules and continued their usual diets for 6 weeks.

Results

56 people completed the study. DHA only reduced 24-hour and daytime (awake) ambulatory BP. Compared to the placebo group, 24-hour BP fell 5.8/3.3 (systolic/diastolic) mm Hg and daytime BP fell 3.5/2.0 mm Hg with DHA. DHA also significantly reduced 24-hour, daytime and night time (asleep) ambulatory HRs. Compared to the placebo group, DHA reduced 24-hour HR by 3 bpm, daytime HR by 3.7 bpm and night time HR by 2. EPA had no significant effect upon ambulatory BP or HR. Supplementation with EPA increased plasma phospholipid EPA from 1.66 to 9.83 but did not change DHA levels. Purified DHA capsules increased plasma phospholipid DHA levels and led to a small, nonsignificant increase in EPA.

Conclusion

Purified DHA but not EPA reduced ambulatory BP and HR in mildly hyperlipidaemic men. These results suggest that DHA is the principal n-3 fatty acid in fish and fish oils responsible for BP- and HR- lowering effects in humans. These data have important implications for human nutrition and the food industry.

References

Mori TA et al. Docosahexaenoic acid but not eicosapentaenoica acid lowers ambulatory blood pressure and heart rate in humans. Hypertension 34(2): 253-60. Aug 1999.