Toenail selenium as an indicator of selenium intake among middle-aged men in an area with low soil selenium.

Toenail selenium concentration has been proposed as a long-term (6-12 mo) indicator of human selenium status. This study investigated the association between toenail selenium concentration and selenium intake and other dietary factors among 166 urban men aged 55-69 y. The dietary information was collected by food records covering a 6-mo period. Toenail clippings were collected by mail 9-10 mo after food recording. The mean selenium intake from food was 42.5 micrograms/d and the dietary intake was equal to that of users and nonusers of selenium supplements. The mean toenail selenium concentration was 0.47 mg/kg. The mean selenium intake from supplements was 29.7 micrograms/d among supplement users. In the analysis of covariance the best predictors of toenail selenium concentration were selenium intake from supplements and food, and among supplement users dietary beta-carotene also.