title: Use of a 13C tracer to quantify the plasma appearance of a physiological dose of lutein in humans.
abstract: Increased intake of lutein from vegetables promotes increased density of the macular pigment and therefore may protect against age-related macular degeneration. Our objective was to use a 13C tracer and high-precision gas chromatography-combustion interfaced-isotope ratio mass spectrometry (GC-C-IRMS) to investigate metabolism of a lutein dose equivalent to that absorbed from vegetables. Biosynthetic per-labeled (>99% 13C) lutein was purified from a commercially available extract of algal biomass. Subjects (n = 4) ingested 3 mg of [13C]lutein with a standardized low-carotenoid breakfast. Blood samples were collected at baseline and then hourly for 12 h; additional blood samples were drawn at 16, 24, 48, 72, 96, 192, 360, and 528 h. To produce perhydro-beta-carotene suitable for analysis by GC-C-IRMS, the plasma lutein fraction was hydrogenated on palladium-on-carbon catalyst with acid-catalyzed hydrogenolysis. The stable carbon isotope (13C/12C) ratio measured by GC-C-IRMS was used to calculate the plasma concentration of [13C]lutein. There was a rapid increase in [13C]lutein in plasma until peak enrichment at 16 h followed by a decline to the next measurement at 24 h. At 528 h, small changes in 13C enrichment from baseline could still be measured in plasma lutein. High-precision GC-C-IRMS enables complete definition of the appearance and disappearance of [13C]lutein in plasma after ingestion of a dose similar to that absorbed from foods.
authors.affiliation: Department of Food Science and Human Nutrition, Iowa State University, Ames 50011, USA.
authors.forename: L
authors.initials: L
authors.lastname: Yao
authors.forename: Y
authors.initials: Y
authors.lastname: Liang
authors.forename: W S
authors.initials: WS
authors.lastname: Trahanovsky
authors.forename: R E
authors.initials: RE
authors.lastname: Serfass
authors.forename: W S
authors.initials: WS
authors.lastname: White
mesh_terms: D000328:Adult; D002247:Carbon Isotopes; D005260:Female; D005638:Fruit; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D014975:Lutein / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014675:Vegetables
chemical_list: D002247:Carbon Isotopes; D014975:Lutein