Zinc and platelet membrane microviscosity in Alzheimer's disease. The in vivo effect of zinc on platelet membranes and cognition.
OBJECTIVE
To investigate the effects of oral zinc supplementation on: (i) plasma zinc concentrations; (ii) platelet membrane microviscosity in vivo; and (iii) cognitive function of Alzheimer's disease (AD) patients.


METHODS
An open-labelled pilot study.


METHODS
University of Stellenbosch Medical School and Stikland Hospital.


METHODS
Six volunteer AD patients.


METHODS
Plasma zinc levels, platelet membrane microviscosity and cognition (MMSE and ADAS-cog tests).


RESULTS
Oral zinc supplementation (30 mg/day) did not increase plasma zinc levels significantly, but significantly increased platelet membrane microviscosity (P = 0.02; 6 patients). Four patients, who underwent 12 months of evaluation, showed modest cognitive improvement on psychometric testing (Mini-Mental State Examination and the cognitive portion of the Alzheimer's Disease Assessment scale scores).


CONCLUSIONS
While earlier literature promoted the use of zinc in AD patients, a recent study has contradicted this and implicated zinc in the aetiology of Alzheimer's disease. On the basis of the above results, it may be premature to single out zinc as a causal agent in AD.
Potocnik
F C
FC
Department of Psychiatry, University of Stellenbosch, Tygerberg, W Cape.
van Rensburg
S J
SJ
Park
C
C
Taljaard
J J
JJ
Emsley
R A
RA
D000368:Aged; D000544:Alzheimer Disease / Q000097:blood* / Q000523:psychology; D001792:Blood Platelets / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008560:Membrane Fluidity; D008875:Middle Aged; D012016:Reference Values; D014783:Viscosity; D015032:Zinc / Q000097:blood*
D015032:Zinc