The importance of trace elements in relation to human health has been increasingly recognized. Accurate and adequate quantification of trace elements are crucial in clinical research.
This review was to discuss the rationale of using nail trace elements as biomarkers in clinical studies.
For most trace elements, dietary instruments can not appropriately capture the intakes because of the minimal amounts and wide variations in the same foods grown in different area as well as the non-dietary exposures. Therefore, biomarkers may be essential in studying trace elements. Although there are notable differences among trace elements in the availability of biomarkers, increasing evidence supports that nail particularly toenail concentrations of most trace elements are useful biomarkers of exposure in which a single sample is assumed to represent long-term exposure.
As compared to other potential biomarkers of trace elements, nail measurement has certain advantages in clinical research.
The importance of trace elements in relation to human health has been increasingly recognized. Trace elements have nutritional benefits as essential cofactors for physiologic processes, but some can be toxic to human health. Accumulated evidence suggests that deficiency or excess of certain trace elements may be associated with risk of chronic diseases including cardiovascular diseases, diabetes and cancer.
Accurate and adequate quantification of trace elements are crucial in clinical research. For most trace elements, dietary instruments such as food frequency questionnaire and 24-hour recall can not appropriately capture the intakes because of the minimal amounts and wide variations in the same foods grown in different area. Also, trace element exposures in humans represent both dietary and non-dietary exposure. Thus, biomarkers of trace elements are preferred over other types of measurements in clinical study both as a measure of intake and as a means to validate other forms of exposure assessment.1
The availability of biomarkers among trace elements is largely different. Most previous studies assessed trace elements in blood, hair, nail or urine specimens, and for some heavy metals, in bone as well. To date, no single source of measurement is the best across all trace elements. Therefore, it is important to understand the strength and weakness of a measurement for trace elements and utilize it appropriately in clinical research.