Hair is essentially an excretory tissue rather than a functional tissue. As the body makes hair, different elements are permanently incorporated into the hair follicle. Scalp hair is easy to sample, and because it grows an average of 1-2cm per month, it contains a time-based record of element metabolism and exposure.
Is hair analysis clinically useful?
There’s a growing number of peer-reviewed papers supporting the value of elemental analysis of hair samples to detect exposure to toxic metals. Once metals are incorporated into the hair follicle there is no back exchange into the body; therefore, the concentration of metals in hair is usually far greater than what can be found in blood or urine samples.
For example, elevated levels of arsenic in both hair and urine confirmed arsenic exposure from a pesticide in an individual with peripheral neuropathy and macrocytosis.1 Hair levels of lead, manganese, cadmium, and other toxic metals have been correlated with psychological conditions and deviant/violent behaviours.2 Lead, cadmium and mercury levels in children’s hair has been correlated with childhood intelligence. Hair analysis has been utilised to identify historical as opposed to current exposure to lead.3 School children with relatively high levels of lead in their hair had slower reaction-times and less flexibility in changing their focus of attention than children with relatively low concentrations of lead in their hair.4 Hair analysis provides important information which, in conjunction with symptoms, medical history and other laboratory results, can warrant further investigation that may identify chronic disorders often associated with abnormal levels of toxic elements.
A hair test estimates recent exposure to toxic elements. Environmental pollution is a growing problem which makes all of us vulnerable to toxic metals in our air, water, food and environment. We are all exposed to toxic elements such as cigarette smoke (cadmium), antiperspirants and antacids (aluminum), tap water in some areas (lead), tooth fillings, fish (mercury), and pesticides (arsenic), to name a few. Toxic elements accumulate with excessive or continual exposure, or if the liver and detoxification pathways are not functioning well, further accumulation of toxic elements will occur.