Long-term selenium status in humans

The association of sub-optimal selenium status with increased riskfactors for some cancers has been reported in two recent epidemiological studies.In both studies the same threshold in selenium status was observed, belowwhich, cancer incidence increased. To assess the use of nails as a biologicmonitor to measure the long-term selenium status, an eight-year longitudinalstudy was undertaken with a group of 11 adult subjects, 5 women and 6 men.Selenium has been measured by instrumental neutron activation analysis. Differencesbetween fingernails and toenails will be discussed. In addition, the resultswill be discussed in the context of the long-term stability of the nail monitorto measure selenium status during those periods when selenium determinantsare static; and the changes that occur as a result of selenium supplementation.