Abstract
Background: Black African (BA) populations are losing the cardio-protective lipid profile they historically exhibited, which may be linked with increasing fructose intakes. The metabolic effects of high fructose diets and how they relate to blood lipids are documented for Caucasians, but have not been described in BA individuals. Objective: The principle objective of this pilot study was to assess the independent impacts of high glucose and fructose feeding in men of BA ancestry compared to men of White European (WE) ancestry on circulating triglyceride (TG) concentrations. Methods: Healthy males, aged 25-60 years, of BA (n=9) and WE (n=11) ethnicity were randomly assigned to 2 feeding days in a crossover design, providing mixed nutrient meals with 20% total daily caloric requirements from either added glucose or fructose. Circulating TG, non-esterified fatty acids (NEFA), glucose, insulin and C-peptide were measured over two 24-h periods. Results: Fasting TGs were lower in BAs than WEs on the fructose feeding day (p<0.05). There was a trend for fasting TG concentrations 24 hours following fructose feeding to increase in both BA (baseline median fasting: 0.80, IQR 0.6-1.1 vs 24-h median post-fructose: 1.09, 0.8-1.4 mmol/L; p=0.06) and WE (baseline median fasting 1.10, IQR 0.9-1.5 vs 24-h median post-fructose: 1.16, IQR 0.96-1.73 mmol/L; p=0.06). Analysis within ethnic group demonstrated that in TG iAUC was significantly higher in BA compared to WE on both glucose (35, IQR 11-56 vs -4, IQR -10-1 mmol/L/min; p=0.004) and fructose (48, IQR 15-68 vs 13, IQR -7-38 mmol/L/min; p=0.04). Greater suppression of postprandial NEFA was evident in WE than BA after glucose feeding (-73, IQR -81- -52 vs -26, IQR -48- -3 nmol/L/min; p=0.001) but there was no ethnic difference following fructose feeding. Conclusions: Understanding the metabolic effects of dietary acculturation and Westernisation that occurs in Black communities is important for developing prevention strategies for chronic disease development. These data show postprandial hypertriglyceridemia following acute feeding of high added fructose and glucose in BA men, compared to WE men, may contribute to metabolic changes observed during dietary acculturation and Westernisation.