The impact of supplemental macular carotenoids in Alzheimer's disease: A randomized clinical trial

John M. Nolan, Ekaterina Loskutova, Alan Howard, Riona Mulcahy, Rachel Moran, Jim Stack, Maggie Bolger, Robert F. Coen, Jessica Dennison, Kwadwo Owusu Akuffo, Niamh Owens, Rebecca Power, David Thurnham, Stephen Beatty

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)


Background: Patients with Alzheimer's disease (AD) exhibit significantly less macular pigment (MP) and poorer vision when compared to control subjects. Objective: To investigate supplementation with the macular carotenoids on MP, vision, and cognitive function in patients with AD versus controls. Methods: A randomized, double-blind clinical trial with placebo and active arms. 31 AD patients and 31 age-similar control subjects were supplemented for six months with either Macushield (10 mg meso-zeaxanthin [MZ]; 10 mg lutein [L]; 2mg zeaxanthin [Z]) or placebo (sunflower oil). MP was measured using dual-wavelength autofluorescence (Heidelberg Spectralis®). Serum L, Z, andMZwere quantified by high performance liquid chromatography. Visual function was assessed by best corrected visual acuity and contrast sensitivity (CS). Cognitive function was assessed using a battery of cognition tests, including the Cambridge Neuropsychological Test Automated Battery (CANTAB). Results: Subjects on the active supplement (for both AD and non-AD controls) exhibited statistically significant improvement in serum concentrations of L, Z, MZ, and MP (p < 0.001, for all) and also CS at (p = 0.039). Also, for subjects on the active supplement, paired samples t-tests exhibited four significant results (from five spatial frequencies tested) in the AD group, and two for the non-AD group, and all indicating improvements in CS. We found no significant changes in any of the cognitive function outcome variables measured (p > 0.05, for all). Conclusion: Supplementation with the macular carotenoids (MZ, Z, and L) benefits patients with AD, in terms of clinically meaningful improvements in visual function and in terms of MP augmentation.

Original languageEnglish
Pages (from-to)1157-1169
Number of pages13
JournalJournal of Alzheimer's Disease
Issue number4
Publication statusPublished - 2015


  • Age-related macular degeneration
  • Alzheimer's disease
  • Cognitive function
  • Contrast sensitivity
  • Lutein
  • Mesozeaxanthin
  • Randomized clinical trial
  • Visual function
  • Zeaxanthin


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