Dose-dependent increases in heart rate variability and arterial compliance in overweight and obese adults with DHA-rich fish oil supplementation

Abstract

Heart rate (HR) variability and large arterial compliance can be improved using fish oils. DHA, a component of fish oil, has cardiovascular health benefits, but its effect on HR variability (HRV) and arterial compliance is yet to be quantified. Sixty-seven overweight or obese adults (thirty-six males and thirty-one females; 53 (SEM 2) year; BMI 31•7 (SEM 1•1) kg/m2) were randomly allocated to consume either 6 g/d sunola oil (control; n 17), fish oil (260 mg DHA þ 60 mg EPA per g) at doses of 2 g/d (n 16), 4 g/d (n 17) or 6 g/d (n 17). Blood pressure, HR and compliance of large and small arteries were measured while supine at baseline and after 12 weeks in all participants, and HRV was assessed in a subgroup of forty-six participants. There was no effect of fish oil on blood pressure, small artery compliance or HR. However, the low frequency:high frequency ratio of HRV decreased with increasing doses of fish oil (r 20•34, P¼0•02), while large artery compliance increased (r 0•34, P¼0•006). Moreover, the changes in these biomarkers were significantly correlated (r 20•31, P¼0•04) and may reflect fish oil-induced improvements in arterial function and cardiac autonomic regulation.