Plain language summary
Vitamin-D deficiency is now considered to effect over 1 billion people world-wide and has known health implications including bone pathologies, immune dysfunction and metabolic diseases. It is thought that vitamin-D deficiency is increasing amongst the population due to our indoor lifestyles and increased use of sunscreens. The current method used to determine vitamin-D status is by measuring the concentration within blood circulation. Although considered accurate, this method can prove inconvenient and costly, especially for those requiring repeat or regular monitoring. A far simpler means of measurement is through hair analysis, although this method is in its infantry. The aim of this study was to investigate whether this method shows consistent markers in vitamin-D status which correlate to those of blood samples and whether hair analysis has potential for further research. The subjects in this study were the three authors who compared vitamin-D markers within their own hair to the markers within their blood serum concentrations. They found that although it is not possible to rely solely on hair analysis to measure vitamin-D status, it is possible to gain a picture of vitamin-D status historically, which can aid epidemiological research. Supplemental intake could also be monitored through longitudinal methods. Whilst the results were varied and inconclusive, the authors do suggest that there is scope for future research. Variations need to be accounted for, such as hair colour, age related differences plus methods of extracting the vitamin from the hair shaft.