Hair zinc, copper and iron: Relationships with quality of diet, tobacco smoking and nutritional status

Abstract

This study was performed in order to analyze the relationship between hair copper, zinc and iron contents (in 94 individuals) and quality of diet (rich in meat, rich in vegetables, rich in fish, recorded by dietary recall on food consumed in the last 2 weeks), body mass index (BMI), tobacco smoking, and living in rural or urban areas. Hair samples were rinsed in 5 ml acationox 0.1% (Scientific Products, McGraw Park, Illinois, IL, USA), and allowed to dry during one night at 60°C; once dried, hair samples were rinsed in acetone and allowed to dry again during one night, were later digested in 0.5 ml HCl (Merck p.a., Darmstadt, Germany) and hydrogen peroxide (Merck p.a., Darmstadt, Germany), solutions were quantitatively transferred to volumetric flasks and diluted to 10 ml with ultrapure water (Milli-Q OM-140 deionization system), and Zn, Cu and Fe were determined in these solutions by flame atomic absorption photometry, using a Varian Spectra spectrophotometer (Mulgrave, Victoria, Australia); detection limits for these elements are 0.009 ppm for Zn, 0.026 for Cu and 0.039 for Fe. Those who consumed vegetables frequently showed higher Fe levels. No relation was observed between fish consumption and any of the trace elements analyzed. Obese individuals showed lower copper (p = 0.042) and a trend to lower iron (p = 0.059) levels. In accordance with these results an inverse, significant relationship was observed between BMI and copper (p = -0.21, p = 0.043). A significant correlation was observed between age and hair copper among men (p = -0.54, p < 0.001). No differences were observed between those who lived in rural areas compared with those who lived in urban areas or between smokers and nonsmokers.