Selective partitioning of dietary fatty acids into the VLDL TG pool in the early postprandial period.
Circulating triacylglycerol (TG) arises mainly from dietary fat. However, little is known about the entry of dietary fat into the major TG pool, very low-density lipoprotein (VLDL) TG. We used a novel method to study the specific incorporation of dietary fatty acids into postprandial VLDL TG in humans. Eight healthy volunteers (age 25.4 +/- 2.2 years, body mass index 22.1 +/- 2.3 kg/m2) were fed a mixed meal containing 30 g fish oil and 600 mg [1-13C]palmitic acid. Chylomicrons and VLDL were separated using immunoaffinity against apolipoprotein B-100. The fatty acid composition of lipoproteins was analyzed by gas chromatography/mass spectrometry. [1-13C]palmitic acid started to appear in VLDL TG 3 h after meal intake, and a similar delay was observed for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Approximately 20% of dietary fatty acids entered the VLDL TG pool 6 h after meal intake. DHA was clearly overincorporated into this pool compared with [1-13C]palmitic acid and EPA. This seemed to depend on a marked elevation of this fatty acid in the nonesterified fatty acid pool. In summary, the contribution of dietary fatty acids to early postprandial VLDL TG is substantial. The role of DHA in VLDL TG production will require further investigation.
Heath
Richard B
RB
Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom.
Karpe
Fredrik
F
Milne
Ross W
RW
Burdge
Graham C
GC
Wootton
Stephen A
SA
Frayn
Keith N
KN
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D004032:Diet; D004041:Dietary Fats / Q000097:blood / Q000494:pharmacology*; D004281:Docosahexaenoic Acids / Q000097:blood; D015118:Eicosapentaenoic Acid / Q000097:blood; D005227:Fatty Acids / Q000097:blood* / Q000494:pharmacology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006801:Humans; D008074:Lipoproteins / Q000097:blood; D008079:Lipoproteins, VLDL / Q000097:blood*; D008297:Male; D019308:Palmitic Acid / Q000097:blood; D019518:Postprandial Period; D014280:Triglycerides / Q000097:blood*
D001786:Blood Glucose; D004041:Dietary Fats; D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; D008074:Lipoproteins; D008079:Lipoproteins, VLDL; D014280:Triglycerides; C030087:lipoprotein triglyceride; C030106:very low density lipoprotein triglyceride; D004281:Docosahexaenoic Acids; D019308:Palmitic Acid; D015118:Eicosapentaenoic Acid