title: The respective relationships between lipoprotein profile, macular pigment optical density, and serum concentrations of lutein and zeaxanthin.
abstract: OBJECTIVE
  The dietary carotenoids lutein (L) and zeaxanthin (Z) are transported on lipoproteins in the serum. The mechanism of delivery of L and Z to the macula, where they constitute macular pigment (MP), is poorly understood. This study was an investigation of the respective relationships between serum lipoprotein profile, MP optical density (MPOD), and serum L and Z.
  
  
  METHODS
  Three hundred two healthy subjects were recruited; 211 (69.9%) were women. Demographic and health details were recorded. Fasting blood samples were taken for lipoprotein analysis by spectrophotometric assay and L and Z analysis by high-performance liquid chromatography. MPOD was measured by heterochromatic flicker photometry.
  
  
  RESULTS
  The mean ± SD (range) age of all subjects was 48 ± 11 (21-66) years. There was a statistically significant and positive association between serum L concentration and both serum cholesterol concentration (r = 0.239, P < 0.001) and serum HDL concentration (r = 0.324, P < 0.001), but not with serum LDL concentration (r = 0.095, P = 0.101). There was a statistically significant but inverse association between serum triglyceride concentration and total MPOD (r = -0.118, P = 0.044). There was no significant association between MPOD and serum cholesterol concentration or serum HDL concentration (P > 0.05).
  
  
  CONCLUSIONS
  The findings are consistent with the hypothesis that HDL is important for the transport of L in serum. The mechanism(s) whereby L and Z are captured by the macula and whether the serum (apo)lipoprotein profile is important in the transfer of the carotenoids from serum to retina merit further study.
authors.affiliation: Macular Pigment Research Group, Department of Chemical and Life Sciences, Waterford Institute of Technology, Waterford, Ireland. edwardloane@yahoo.com
authors.forename: Edward
authors.initials: E
authors.lastname: Loane
authors.forename: John M
authors.initials: JM
authors.lastname: Nolan
authors.forename: Stephen
authors.initials: S
authors.lastname: Beatty
mesh_terms: D000328:Adult; D000368:Aged; D002784:Cholesterol / Q000097:blood*; D008076:Cholesterol, HDL / Q000097:blood*; D008078:Cholesterol, LDL / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D014975:Lutein / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010783:Photometry; D012168:Retinal Pigments / Q000378:metabolism*; D011795:Surveys and Questionnaires; D014280:Triglycerides / Q000097:blood*; D024341:Xanthophylls / Q000097:blood*; D055815:Young Adult; D065146:Zeaxanthins
chemical_list: D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D012168:Retinal Pigments; D014280:Triglycerides; D024341:Xanthophylls; D065146:Zeaxanthins; D002784:Cholesterol; D014975:Lutein