Correlates of toenail zinc in a free-living U.S. population.
OBJECTIVE
No prior studies have reported on dietary correlates of toenail zinc, an easily collected biomarker of zinc status. The study aim was to identify dietary and other factors that influence toenail zinc in a healthy population, in order to understand the usefulness of this biomarker in public health studies.


METHODS
Cross-sectional comparison of toenail zinc with questionnaire measures of demographic and behavioral factors, dietary intake and supplement use.


METHODS
Western Washington State, US.


METHODS
106 men and 106 women, who are participants in a large cohort study, of whom 66% used multivitamins or individual supplements containing zinc.


RESULTS
Increased toenail zinc concentrations were associated with increased dietary zinc intake (adjusted difference in toenail zinc between those in the highest quartile of intake vs. lowest = 11.0 ppm, p for trend = 0.03), with the association primarily among men. Borderline associations of increased toenail zinc were found with decreased vegetable intake (p=0.08) and increased body mass index (p=0.11). Supplemental zinc and intake of phytic acid, alcohol, iron (from food or supplements) did not influence toenail zinc.


CONCLUSIONS
Toenail zinc concentrations vary with dietary zinc intake, even in a healthy population with presumably little zinc deficiency.
Gonzalez
Alejandro
A
Cancer Prevention Program, Fred Hutchinson Cancer Research Center, and Nutritional Sciences Program, University of Washington, Seattle, WA 98109-1024, USA.
Peters
Ulrike
U
Lampe
Johanna W
JW
Satia
Jessie A
JA
White
Emily
E
D000368:Aged; D003430:Cross-Sectional Studies; D004032:Diet / Q000706:statistics & numerical data*; D019587:Dietary Supplements / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009262:Nails / Q000737:chemistry*; D011795:Surveys and Questionnaires; D014861:Washington; D015032:Zinc / Q000032:analysis*
D015032:Zinc