Methods of assessment of zinc status in humans: a systematic review.
BACKGROUND
Zinc is an essential micronutrient for human health and has numerous structural and biochemical roles. The search for a reliable, sensitive, and specific index of zinc status has been the subject of considerable research, which has resulted in the identification of a number of potentially useful biomarkers.


OBJECTIVE
The objective was to assess the usefulness of biomarkers of zinc status in humans.


METHODS
The methods included a structured search strategy using Ovid MEDLINE, EMBASE (Ovid), and the Cochrane Library CENTRAL databases; formal inclusion and exclusion criteria; data extraction into an Access database; quality and validity assessment; and meta-analysis.


RESULTS
Data on 32 potential biomarkers from 46 publications were analyzed. Plasma zinc concentration responded in a dose-dependent manner to dietary manipulation in adults, women, men, pregnant and lactating women, the elderly, and those at low and moderate baseline zinc status. Urinary zinc excretion responded to zinc status overall and in all subgroups for which there were sufficient data. Hair zinc concentration also responded, but there were insufficient studies for subgroup analysis. Platelet, polymorphonuclear cell, mononuclear cell, and erythrocyte zinc concentration and alkaline phosphatase activity did not appear to be effective biomarkers of zinc status.


CONCLUSIONS
This systematic review confirms that in healthy individuals, plasma, urinary, and hair zinc are reliable biomarkers of zinc status. Further high-quality studies using these biomarkers are required, particularly in infants, adolescents, and immigrant population groups for whom there are limited data. Studies are also required to fully assess a range of additional potential zinc biomarkers.
Lowe
Nicola M
NM
Centre for Applied Sport and Exercise Sciences, School of Psychology, the University of Central Lancashire, Preston, United Kingdom. nmlowe@uclan.ac.uk
Fekete
Katalin
K
Decsi
Tamás
T
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis*; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D006197:Hair / Q000737:chemistry; D006801:Humans; D008297:Male; D008722:Methods; D015596:Nutrition Assessment; D009752:Nutritional Status; D011247:Pregnancy; D014131:Trace Elements / Q000032:analysis* / Q000097:blood / Q000652:urine; D015032:Zinc / Q000032:analysis* / Q000097:blood / Q000652:urine
D015415:Biomarkers; D014131:Trace Elements; D015032:Zinc