Postprandial enrichment of triacylglycerol-rich lipoproteins with omega-3 fatty acids: lack of an interaction with apolipoprotein E genotype?

BACKGROUND: We have previously demonstrated that carrying the apolipoprotein (apo) E epsilon 4 (E4+) genotype disrupts omega-3 fatty acids (n − 3 PUFA) metabolism. Here we hypothesise that the postprandial clearance of n − 3 PUFA from the circulation is faster in E4+ compared to non-carriers (E4−). The objective of the study was to investigate the fasted and postprandial fatty acid (FA) profile of triacylglycerol-rich lipoprotein (TRL) fractions: S(f) >400 (predominately chylomicron CM), S(f) 60 − 400 (VLDL(1)), and S(f) 20 − 60 (VLDL(2)) according to APOE genotype. METHODS: Postprandial TRL fractions were obtained in 11 E4+ (ϵ3/ϵ4) and 12 E4− (ϵ3/ϵ3) male from the SATgenϵ study following high saturated fat diet + 3.45 g/d of docosahexaenoic acid (DHA) for 8-wk. Blood samples were taken at fasting and 5-h after consuming a test-meal representative of the dietary intervention. FA were characterized by gas chromatography. RESULTS: At fasting, there was a 2-fold higher ratio of eicosapentaenoic acid (EPA) to arachidonic acid (P = 0.046) as well as a trend towards higher relative% of EPA (P = 0.063) in the S(f) >400 fraction of E4+. Total n − 3 PUFA in the S(f) 60 − 400 and S(f) 20 − 60 fractions were not APOE genotype dependant. At 5 h, there was a trend towards a time × genotype interaction (P = 0.081) for EPA in the S(f) >400 fraction. When sub-groups were form based on the level of EPA at baseline within the S(f) >400 fraction, postprandial EPA (%) was significantly reduced only in the high-EPA group. EPA at baseline significantly predicted the postprandial response in EPA only in E4+ subjects (R(2) = 0.816). CONCLUSION: Despite the DHA supplement contain very low levels of EPA, E4+ subjects with high EPA at fasting potentially have disrupted postprandial n − 3 PUFA metabolism after receiving a high-dose of DHA. TRIAL REGISTRATION: Registered at clinicaltrials.gov/show/NCT01544855.