Effect of acute walking on endothelial function and postprandial lipaemia in South Asians and white Europeans

Introduction: South Asians (SAs) have an elevated risk of cardiovascular disease (CVD) compared to white Europeans (WEs). Postprandial endothelial function (FMD%) in SA women, and SA men with central obesity, has not been investigated. Research in other populations has highlighted a 1% higher FMD% is associated with a ~ 13% lower risk of future CVD events. We investigated whether FMD% and lipaemia, two markers for CVD risk, were higher in SAs vs. WEs, whether walking improved FMD% and lipaemia, and if there were ethnic differences in the response. Methods: Lean premenopausal women (study one; 12 SA, 12 WE), and men with central obesity (study two; 15 SA, 15 WE) completed two 2-d trials. On day one, participants walked for 60-mins at 60% of their peak oxygen uptake or rested. On day two, participants rested and consumed two high-fat meals over 8-h. Repeated ultrasound assessments of endothelial function and venous blood samples for CVD risk markers were taken. Results: Compared to WEs, SAs had lower postprandial FMD% (study one: -1.32%; study two: -0.54%) and higher postprandial triacylglycerol concentrations (study one: 0.31 mmol/L h; study two: 0.55 mmol/L h). Walking improved postprandial FMD% (study one: 1.12%, study two: 0.94%) and resulted in no significant change or small reductions in postprandial triacylglycerol concentrations (study one: -0.01 mmol/L h; study two: -0.25 mmol/L h). Exercise-induced changes in FMD% and triacylglycerol were consistent between ethnic groups. Conclusions: Walking mitigated the adverse postprandial effect of a high-fat diet on FMD% to a similar extent in SA and WE women and men, even with no/small improvements in triacylglycerol. This study highlights the importance of exercise to clinically improve FMD% in SAs and WEs.