title: Zinc diet and Alzheimer's disease: a systematic review.
abstract: OBJECTIVE
  This paper reviews evidence of an association between zinc (Zn) nutrition and Alzheimer's disease (AD) or age-associated cognitive decline. The involvement of zinc in the pathology of AD has been reported hundreds of times. It is, however, still a matter of debate  whether the disease progression can be influenced by modifying zinc in the diet.
  
  
  METHODS
  We searched Medline, Embase, Biosis, ALOIS, the Cochrane central register of controlled trials, the Cochrane database of systematic reviews, and different publisher databases, and included  studies that dealt with zinc in the diet and AD or cognitive decline in elderly subjects.
  
  
  RESULTS
  Fifty-five studies met the inclusion criteria. Neither randomized-controlled trials nor observational studies provide conclusive evidence whether Zn in the diet is associated  with cognitive decline or AD. Case-control and autopsy studies suggest decreased systemic and increased brain Zn levels, respectively.
  
  
  CONCLUSIONS
  The current state of evidence does not allow conclusions to be drawn on whether supplementation of Zn is beneficial for the  prevention or treatment of AD, although a subclinical deficiency appears common in the elderly and subjects with AD. Dietary studies with animals suggest that the impact of dietary Zn on cognitive performance depend on additional nutrients. Further studies are necessary to determine whether  Zn deficiency is a risk factor for AD in general terms or under certain dietary circumstances only.
authors.affiliation: European University Viadrina, Institute of Transcultural Health Studies, Frankfurt (Oder), Germany/Samueli Institute, European Office, Frankfurt (Oder), Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Loef
authors.forename: Nikolaus
authors.initials: N
authors.lastname: von Stillfried
authors.forename: Harald
authors.initials: H
authors.lastname: Walach
mesh_terms: D000544:Alzheimer Disease / Q000178:diet therapy* / Q000453:epidemiology / Q000473:pathology*; D000818:Animals; D019587:Dietary Supplements; D006801:Humans; D012307:Risk Factors; D014131:Trace Elements / Q000008:administration & dosage* / Q000009:adverse effects; D015032:Zinc / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D014131:Trace Elements; D015032:Zinc