title: Serum and macular response to carotenoid-enriched egg supplementation in human subjects: the Egg Xanthophyll Intervention clinical Trial (EXIT).
abstract: The macular carotenoids lutein (L), zeaxanthin (Z) and meso-zeaxanthin (MZ) accumulate at the macula, where they are collectively referred to as macular pigment (MP). Augmentation of this pigment, typically achieved through diet and supplementation, enhances visual function and protects against progression of age-related macular degeneration. However, it is known that eggs are a rich dietary source of L and Z, in a highly bioavailable matrix. In this single-blind placebo-controlled study, L- and MZ-enriched eggs and control non-enriched eggs were fed to human subjects (mean age 41 and 35 years, respectively) over an 8-week period, and outcome measures included MP, visual function and serum concentrations of carotenoids and cholesterol. Serum carotenoid concentrations increased significantly in control and enriched egg groups, but to a significantly greater extent in the enriched egg group (P<0·001 for L, Z and MZ). There was no significant increase in MP in either study group post intervention, and we saw no significant improvement in visual performance in either group. Total cholesterol increased significantly in each group, but it did not exceed the upper limit of the normative range (6·5 mmol/l). Therefore, carotenoid-enriched eggs may represent an effective dietary source of L, Z and MZ, reflected in significantly raised serum concentrations of these carotenoids, and consequentially improved bioavailability for capture by target tissues. However, benefits in terms of MP augmentation and /or improved visual performance were not realised over the 8-week study period, and a study of greater duration will be required to address these questions.
authors.affiliation: 1Macular Pigment Research Group,Nutrition Research Centre Ireland,School of Health Sciences,Waterford Institute of Technology,Waterford X91 K236,Republic of Ireland.
authors.forename: David
authors.initials: D
authors.lastname: Kelly
authors.affiliation: 1Macular Pigment Research Group,Nutrition Research Centre Ireland,School of Health Sciences,Waterford Institute of Technology,Waterford X91 K236,Republic of Ireland.
authors.forename: John M
authors.initials: JM
authors.lastname: Nolan
authors.affiliation: 2Howard Foundation,Cambridge CB25 ONW,UK.
authors.forename: Alan N
authors.initials: AN
authors.lastname: Howard
authors.affiliation: 1Macular Pigment Research Group,Nutrition Research Centre Ireland,School of Health Sciences,Waterford Institute of Technology,Waterford X91 K236,Republic of Ireland.
authors.forename: Jim
authors.initials: J
authors.lastname: Stack
authors.affiliation: 1Macular Pigment Research Group,Nutrition Research Centre Ireland,School of Health Sciences,Waterford Institute of Technology,Waterford X91 K236,Republic of Ireland.
authors.forename: Kwadwo O
authors.identifier: 0000-0001-6683-249X
authors.initials: KO
authors.lastname: Akuffo
authors.affiliation: 1Macular Pigment Research Group,Nutrition Research Centre Ireland,School of Health Sciences,Waterford Institute of Technology,Waterford X91 K236,Republic of Ireland.
authors.forename: Rachel
authors.initials: R
authors.lastname: Moran
authors.affiliation: 4Northern Ireland Centre for Food and Health (NICHE),University of Ulster,Coleraine BT52 1SA,UK.
authors.forename: David I
authors.initials: DI
authors.lastname: Thurnham
authors.affiliation: 1Macular Pigment Research Group,Nutrition Research Centre Ireland,School of Health Sciences,Waterford Institute of Technology,Waterford X91 K236,Republic of Ireland.
authors.forename: Jessica
authors.initials: J
authors.lastname: Dennison
authors.affiliation: 1Macular Pigment Research Group,Nutrition Research Centre Ireland,School of Health Sciences,Waterford Institute of Technology,Waterford X91 K236,Republic of Ireland.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Meagher
authors.affiliation: 1Macular Pigment Research Group,Nutrition Research Centre Ireland,School of Health Sciences,Waterford Institute of Technology,Waterford X91 K236,Republic of Ireland.
authors.forename: Stephen
authors.initials: S
authors.lastname: Beatty
mesh_terms: D000328:Adult; D004032:Diet; D004531:Eggs / Q000032:analysis*; D005260:Female; D005504:Food Analysis; D006801:Humans; D008266:Macula Lutea / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D009747:Nutritional Physiological Phenomena; D014785:Vision, Ocular / Q000187:drug effects; D024341:Xanthophylls / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D024341:Xanthophylls
keywords: 
                 Meso-zeaxanthin;  BCVA best-corrected visual acuity;  CS contrast sensitivity;  CisZ 
                    cis-zeaxanthin
                 ;  EXIT Egg Xanthophyll Intervention clinical Trial;  L lutein;  MP macular pigment;  MZ 
                    meso-zeaxanthin
                 ;  TZ total zeaxanthin;  WIT Waterford Institute of Technology;  Z zeaxanthin;  cpd cycles per degree; Carotenoid-enriched eggs; Cholesterol; Lutein; Macular pigment; Serum carotenoids; Zeaxanthin