Abstract
Objectives: Despite lower fasting triglyceride (TG), populations of black African/Caribbean (BAC) ancestry suffer disproportional cardiometabolic risk. However, little is known about postprandial TG metabolism. We aimed to compare postprandial TG metabolism between men of white European (WE) and BAC ancestry.
Methods: Ten WE and 8 BAC healthy but overweight men, age 25–40-yrs, were fed two consecutive high fat meals containing 50 g fat at 0-mins and 30 g fat at 300-mins; the former contained 0.2 g U-13C palmitate to trace incorporation of exogenous TG into postprandial chylomicron (CM) and very low-density lipoprotein (VLDL)/CM remnants. Plasma lipoprotein TG were separated by density gradient ultracentrifugation. For plasma and lipoprotein TG, fatty acid methyl esters were measured by gas chromatography mass spectrometry. Inclusion of an internal standard allowed quantification of U-13C palmitate concentration which is presented as area under the curve (13C-AUC0−480 mins). Fasting TG was measured using an automated assay. Normally distributed data were analysed using independent samples t-test (mean ± SD). Skewed data were Log transformed or analysed with Mann-Whitney U (median [IQR]).
Results: By design, there were no differences in age (WE: 33 ± 5; BAC: 30 ± 4 years, p = 0.13) or BMI (WE: 26.8 (IQR 25.8, 31.0); BAC: 27.6 (IQR 26.2, 29.3) kg/m2 , p = 0.70) between the groups, however the BAC men had significantly lower fasting TG (WE: 1.41 ± 0.78; BAC: 0.76 ± 0.40 mmol/L, p = 0.02). There were no differences in postprandial plasma TG 13C-AUC0–480 (WE: 524.4 ± 176.9 vs. BAC: 610.6 ± 367.9 μ−1 , p = 0.53) or CM TG 13C-AUC0–480 (WE: 321.1 ± 132.6 vs. BAC: 327.5 ± 181.4 μmol/L.min−1 , p = 0.91) between the groups. However, BAC men exhibited significantly lower VLDL/CM remnant TG 13C-AUC0–480 compared to WE (79.2 ± 35.3 vs. 115.5 ± 37.6 μmol/L.min−1 respectively, p = 0.03).
Conclusions: Following fat consumption, lower incorporation of exogenous TG into VLDL/CM remnants, suggestive of more efficient clearance of exogenous TG from the circulation, in BAC men may be cardioprotective. This may be driven by lower visceral fat and/or intrahepatic lipid, typically observed in people of BAC ancestry.