title: Effect of Vitamin Intake on Cognitive Decline in Older Adults: Evaluation of the Evidence.
abstract: OBJECTIVE
  The objective of this review was to evaluate the evidence from human studies on the intake of vitamins, either as monotherapies or in combination with other vitamins, as neuroprotective agents that may delay the onset of cognitive decline in older adults.
  
  
  METHODS
  Evidence-based methodologies were used to capture and evaluate the highest levels of evidence.
  
  
  RESULTS
  The current evidence available showed no association for cognitive benefits of vitamins B6 or B12 as a monotherapy, and recent systematic reviews provide no clear evidence that supplementation with vitamin B6, B12 and/or folic acid improves dementia outcomes or slows cognitive decline, even though it may normalise homocysteine levels. Meta-analyses from systematic reviews have shown an association between low vitamin D levels and diminished cognitive function, although causality cannot be confirmed from the available evidence. There is no convincing evidence for an association of vitamin A, vitamin C or vitamin E either as a monotherapy or in combination with other antioxidant vitamins such as β-carotene and the prevention of cognitive decline. The appraisal of nineteen systematic reviews and meta-analyses has highlighted the heterogeneity between studies, and the need for better consensus on definitions of cognitive decline, duration of testing and agreement on which specific endpoints are clinically relevant.
  
  
  CONCLUSIONS
  Evaluation of the totality of the currently available evidence indicates that intake of the above vitamins, either as a monotherapy, or in combination with other vitamins, has no clinically-relevant effect on delaying cognitive decline or delaying the onset of dementia in older adults.
authors.affiliation: Debra Krause, CSIRO Food and Nutrition Flagship, Private Bag 16, 671 Sneydes Road, Werribee 3030, Victoria, Australia, E-mail: debra.krause@csiro.au, Telephone: +61 3 9731 3280, Fax: +61 3 9731 3201.
authors.forename: D
authors.initials: D
authors.lastname: Krause
authors.forename: P
authors.initials: P
authors.lastname: Roupas
mesh_terms: D000368:Aged; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000150:complications / Q000517:prevention & control*; D003704:Dementia / Q000150:complications / Q000517:prevention & control*; D019587:Dietary Supplements; D005492:Folic Acid / Q000494:pharmacology; D006710:Homocysteine / Q000378:metabolism; D006801:Humans; D015201:Meta-Analysis as Topic; D014801:Vitamin A / Q000494:pharmacology; D014805:Vitamin B 12 / Q000494:pharmacology; D025101:Vitamin B 6 / Q000494:pharmacology; D014807:Vitamin D / Q000494:pharmacology; D014808:Vitamin D Deficiency / Q000150:complications; D014810:Vitamin E / Q000494:pharmacology; D014815:Vitamins / Q000494:pharmacology*; D019207:beta Carotene / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D014815:Vitamins; D019207:beta Carotene; D006710:Homocysteine; D014801:Vitamin A; D014807:Vitamin D; D014810:Vitamin E; D025101:Vitamin B 6; D005492:Folic Acid; D014805:Vitamin B 12; D001205:Ascorbic Acid