'Tracing elements' in hair.

Sir,

Micronutrients form an intricate yet integral part of human body and analysis of hair, in terms of their properties, gives us volumes of information on diseases, metabolic disorders, environmental exposures, and nutritional status. A review exploring the same is being presented.

A study showed that breast cancer patients had low hair calcium, magnesium, and zinc, but high arsenic, sodium, and potassium compared with the normal controls. Hair zinc level had significant negative correlation with body mass index (BMI) in breast cancer patients, which was not seen in normal controls.[1] Hair iron level is shown to be significantly low and is associated with hair calcium and manganese levels in breast cancer. Lung cancer patients (and smokers) sport a higher hair average-cadmium concentration at different stages as compared to controls.

The micronutrient deficiency may disrupt the enzyme functions and has shown to frequently result in metabolic disturbances. A cross-sectional analysis on 343 subjects showed that those with metabolic syndrome had significantly lower contents of hair calcium, magnesium, and copper, whereas the amounts of sodium, potassium, and mercury in the metabolic syndrome group were significantly higher. The optimal calcium and magnesium concentrations in hair tissue may reflect decreased risk of metabolic syndrome, whereas high mercury concentration in hair tissue may indicate increased risk of metabolic syndrome.[2]

Hair samples in autistic children show significantly high levels of copper, lead, mercury, and uranium, while magnesium, zinc, and selenium are significantly low (correlate with severity of autism/degree of functioning).

Hair mineral content reflects exposure of elements from the diet. A study showed that consuming highly processed food causes increased levels of sodium and phosphorous in hair, while slimming foods result in increased content of aluminum, chromium, and titanium. Laxatives may cause lower level of lead, while those on analgesics have more silicon in their hair. While coffee elevates aluminum, nickel, sulfur, and titanium and lowers lead in hair, tea reduces the level of mercury.[3]

Hair zinc, selenium, and copper deficiencies are noted in chronic gastrointestinal diseases. Parenteral nutrition significantly lowers hair zinc concentration (and may heighten fluoride toxicity). The hair selenium concentration correlates with hair loss, brittle hair, and loss of hair pigmentation and selenium supplementation is shown to improve alopecia. Zinc is characteristically low in alopecia areata, especially when extensive, prolonged, and resistant to treatment.[4]

Sodium, chromium, sulfur, and cadmium in the hair correlate positively, while zinc correlates negatively with age. Hair sodium, potassium, chromium, and cadmium have positive correlations with BMI. Low hair selenium is believed to hasten disability and degeneration.

Testing hair for boron (beneficial for bone growth and maintenance, central nervous system function, and the inflammatory response), silicon (for bone maintenance and wound healing), and fluoride (bone strength) likewise elucidates the metabolic status of the patients.

Epileptic patients are shown to have significantly lower levels of Cu and iron and a higher Cu/Fe ratio (females have lower Mg) compared to controls.[5]

Testing hair for trace elements is an underrated but effective approach in deciphering a plethora of disorders.