Low heart rate variability (HRV) predicts sudden cardiac death. Long-chain (LC) n-3 PUFA (C20-C22) status is positively associated with HRV. This cross-sectional study investigated whether vegans aged 40-70 years (n 23), whose diets are naturally free from EPA (20 : 5n-3) and DHA (22 : 6n-3), have lower HRV compared with omnivores (n 24). Proportions of LC n-3 PUFA in erythrocyte membranes, plasma fatty acids and concentrations of plasma LC n-3 PUFA-derived lipid mediators were significantly lower in vegans. Day-time interbeat intervals (IBI), adjusted for physical activity, age, BMI and sex, were significantly shorter in vegans compared with omnivores (mean difference -67 ms; 95 % CI -130, -3·4, P50 % and high-frequency power) were similarly lower in vegans, with no differences during sleep. In conclusion, vegans have higher 24 h SDNN, but lower day-time HRV and shorter day-time IBI relative to comparable omnivores. Vegans may have reduced availability of precursor markers for pro-resolving lipid mediators; it remains to be determined whether there is a direct link with impaired cardiac function in populations with low-n-3 status.
Keywords: n-3 PUFA; %E percentage of energy; HDHA hydroxydocosahexaenoic acid; HF high-frequency power; HR heart rate; HRV heart rate variability; IBI interbeat intervals; LC long chain; LF low-frequency power; RMSSD root of the mean of the sum of the squares of differences between adjacent normal-to-normal intervals; SDANN standard deviation of the average 5-min normal-to-normal intervals; SDNN standard deviation of normal-to-normal intervals; SPM; VLF very-low-frequency power; pNN50 percentage of adjacent normal-to-normal intervals that differ by >50 %; specialised pro-resolving lipid mediators; CHD; Eicosanoids; Heart rate variability; Inflammation; Lipid mediators; Vegans.