title: Supplementation with macular carotenoids reduces psychological stress, serum cortisol, and sub-optimal symptoms of physical and emotional health in young adults.
abstract: OBJECTIVE
  Oxidative stress and systemic inflammation are the root cause of several deleterious effects of chronic psychological stress. We hypothesize that the antioxidant and anti-inflammatory capabilities of the macular carotenoids (MCs) lutein, zeaxanthin, and meso-zeaxanthin could, via daily supplementation, provide a dietary means of benefit.
  
  
  METHODS
  A total of 59 young healthy subjects participated in a 12-month, double-blind, placebo-controlled trial to evaluate the effects of MC supplementation on blood cortisol, psychological stress ratings, behavioural measures of mood, and symptoms of sub-optimal health. Subjects were randomly assigned to one of three groups: placebo, 13 mg, or 27 mg / day total MCs. All parameters were assessed at baseline, 6 months, and 12 months. Serum MCs were determined via HPLC, serum cortisol via ELISA, and macular pigment optical density (MPOD) via customized heterochromatic flicker photometry. Behavioural data were obtained via questionnaire.
  
  
  RESULTS
  Significant baseline correlations were found between MPOD and Beck anxiety scores (r = -0.28; P = 0.032), MPOD and Brief Symptom Inventory scores (r = 0.27; P = 0.037), and serum cortisol and psychological stress scores (r = 0.46; P < 0.001). Supplementation for 6 months improved psychological stress, serum cortisol, and measures of emotional and physical health (P < 0.05 for all), versus placebo. These outcomes were either maintained or improved further at 12 months.
  
  
  CONCLUSIONS
  Supplementation with the MCs significantly reduces stress, cortisol, and symptoms of sub-optimal emotional and physical health. Determining the basis for these effects, whether systemic or a more central (i.e. brain) is a question that warrants further study.
authors.affiliation: a Interdisciplinary Neuroscience Program, Biomedical and Health Sciences Institute , University of Georgia , Athens, GA 30602, USA.|b Department of Psychology , University of Georgia , Athens, GA 30602, USA.
authors.forename: Nicole Tressa
authors.identifier: http://orcid.org/0000-0003-1721-7882
authors.initials: NT
authors.lastname: Stringham
authors.affiliation: a Interdisciplinary Neuroscience Program, Biomedical and Health Sciences Institute , University of Georgia , Athens, GA 30602, USA.|b Department of Psychology , University of Georgia , Athens, GA 30602, USA.
authors.forename: Philip V
authors.initials: PV
authors.lastname: Holmes
authors.affiliation: b Department of Psychology , University of Georgia , Athens, GA 30602, USA.
authors.forename: James M
authors.identifier: http://orcid.org/0000-0002-1476-1084
authors.initials: JM
authors.lastname: Stringham
mesh_terms: D000293:Adolescent; D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage*; D001526:Behavioral Symptoms / Q000523:psychology; D002338:Carotenoids / Q000008:administration & dosage*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D014975:Lutein / Q000008:administration & dosage / Q000097:blood; D008266:Macula Lutea; D065348:Macular Pigment / Q000494:pharmacology; D008297:Male; D012168:Retinal Pigments; D057566:Self Report; D013315:Stress, Psychological / Q000178:diet therapy*; D055815:Young Adult; D065146:Zeaxanthins / Q000008:administration & dosage / Q000097:blood
chemical_list: D000975:Antioxidants; D065348:Macular Pigment; D012168:Retinal Pigments; D065146:Zeaxanthins; D002338:Carotenoids; C584722:meso-zeaxanthin; D006854:Hydrocortisone; D014975:Lutein
keywords: Anxiety; Cortisol; Depression; Health; Lutein; Macular pigment; Stress; Zeaxanthin