title: Postprandial appearance of dietary deuterated cholesterol in the chylomicron fraction and whole plasma in healthy subjects.
abstract: This study examined the appearance of dietary cholesterol in the chylomicron fraction (chylomicrons plus chylomicron remnants) and whole plasma in healthy normolipidemic subjects during a 0-7-h postprandial period. Six adult males were given two diet sequences in random order: a low-fiber diet (standard Western diet for 14 d) followed by a labeled low-fiber test meal or a fiber-supplemented diet (40 g oat bran/d for 14 d) followed by a labeled oat bran (40 g) test meal. The test meals provided 192.5 mg cholesterol, including 80.1 mg octadeuterated cholesterol. Fasting and hourly postmeal blood samples were obtained for 7 h. Isotopic cholesterol ratios [tracer:(tracer+native cholesterol)] were determined by gas chromatography-mass spectrometry. Chylomicron triacylglycerol and cholesterol concentrations peaked after 2-3 h and returned to baseline after 7 h. After the low-fiber test meal, the isotopic cholesterol ratio continuously increased until 7 h in the chylomicron fraction (4.2 +/- 1.2 x 10(-3)) and whole plasma (1.04 +/- 0.39 x 10(-3)). At 7 h postprandial, the maximum dietary cholesterol concentration in the chylomicron fraction and plasma cholesterol was 1 in 99 and 1 in 397 cholesterol molecules, respectively. No marked differences were obtained after the high-fiber sequence compared with the low-fiber one; there was a comparable isotopic cholesterol ratio and concentration in the chylomicron fraction and a slightly lower (-44%, P < 0.10) 0-7 h area under the curve whole-plasma deuterated cholesterol concentration. Thus, dietary cholesterol supplied as a single meal does not simultaneously appear in the chylomicron fraction postprandially with endogenous cholesterol and triacylglycerols and fiber feeding does not markedly alter this process in healthy normolipidemic humans.
authors.affiliation: Unité 130-INSERM (Institut National de la Santé et de la Recherche Medicale), Marseille, France.
authors.forename: C
authors.initials: C
authors.lastname: Dubois
authors.forename: M
authors.initials: M
authors.lastname: Armand
authors.forename: J
authors.initials: J
authors.lastname: Ferezou
authors.forename: G
authors.initials: G
authors.lastname: Beaumier
authors.forename: H
authors.initials: H
authors.lastname: Portugal
authors.forename: A M
authors.initials: AM
authors.lastname: Pauli
authors.forename: P M
authors.initials: PM
authors.lastname: Bernard
authors.forename: T
authors.initials: T
authors.lastname: Becue
authors.forename: H
authors.initials: H
authors.lastname: Lafont
authors.forename: D
authors.initials: D
authors.lastname: Lairon
mesh_terms: D000328:Adult; D002791:Cholesterol, Dietary / Q000097:blood*; D002914:Chylomicrons / Q000097:blood*; D003903:Deuterium; D005502:Food; D006801:Humans; D007700:Kinetics; D008297:Male; D014280:Triglycerides / Q000097:blood
chemical_list: D002791:Cholesterol, Dietary; D002914:Chylomicrons; D014280:Triglycerides; D003903:Deuterium