Effect of n-3 fatty acids on heart rate variability and baroreflex sensitivity in middle-aged subjects.
BACKGROUND
N-3 fatty acids may reduce the risk of sudden death by preventing life-threatening cardiac arrhythmias. Heart rate variability (HRV) and baroreflex sensitivity (BRS) reflect cardiac autonomic regulation; reduced values predict arrhythmic events and mortality. Effects of n-3 fatty acids on these risk indicators of arrhythmia have not been widely studied. We investigated the effect of supplemental intake of n-3 fatty acids on HRV and BRS in apparently healthy subjects aged 50 to 70 years.


METHODS
After a run-in period of 4 weeks, 84 subjects were randomized to receive capsules with either 3.5 g of fish oil or placebo oil daily for 12 weeks. Before and after intervention, electrocardiograms and blood pressure were recorded for 10 minutes with standardized respiration of 15 breaths/min. The SD of the duration of all normal RR intervals (SDNN10) and the root mean square successive differences (RMSSD10) were calculated from the 10-minute recordings. We also computed low frequency power (LF) and high frequency power (HF). BRS was computed by integrating the spectral systolic blood pressure to interbeat-interval transfer function in the 0.05- to 0.15-Hz band.


RESULTS
The different measures of HRV and BRS did not significantly improve with the intake of n-3 fatty acids. SDNN10 decreased by 3.05 ms or 7.7% (95% CI, -8.91-2.82 ms), and BRS decreased by 0.92 ms/mm Hg or 0.1% (95% CI, -2.66-0.81 ms/mm Hg) in the fish oil group compared with the placebo group.


CONCLUSIONS
N-3 fatty acids have no effect on HRV from short-term recordings and BRS in apparently healthy subjects.
Geelen
Anouk
A
Wageningen Centre for Food Sciences, Wageningen, The Netherlands. anouk.geelen@wur.nl
Zock
Peter L
PL
Swenne
Cees A
CA
Brouwer
Ingeborg A
IA
Schouten
Evert G
EG
Katan
Martijn B
MB
D000368:Aged; D017704:Baroreflex / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D004311:Double-Blind Method; D005227:Fatty Acids / Q000097:blood; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D005260:Female; D005395:Fish Oils; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted
D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D005395:Fish Oils