Age and Gender-Based Comparison of Nickel Content of Scalp Hair of Edible Oil- and Hydrogenated Oil-Consuming Populations

Nickel concentrations (μ g/g, dry weight) in the scalp hair of vegetable oil– and hydrogenated oil–consuming categories of male and female donors, ages between 1–66 years, were estimated by the atomic absorption method to assess the contribution of nickel as a contaminant in the hydrogenated oil. Comparative estimates of hair Ni content revealed enhanced metal levels for donors consuming hydrogenated oil both for male (29.33 μg/g, dry weight) and female (27.09 μg/g, dry weight) population segments, whereas for oil-consuming donors the corresponding levels were 11.51 μg/g and 13.49 μg/g, respectively. The Ni content of hair of elderly donors consuming hydrogenated oil was found significantly higher than that of younger male/female donors. Hair Ni levels as high as 63.59 μg/g and 68.40 μg/g were estimated for hydrogenated oil–consuming males and females, respectively. The Ni concentrations exhibited strong positive correlation with age for the hydrogenated oil–consuming male (r = 0.713) and female (r = 0.707) categories, whereas negative correlations were found for both oil-consuming categories. The regression relationships linking hair nickel content with the donor age of either sex indicated a negative dependence for oil-consuming donors, whereas strong direct dependence was observed for hydrogenated oil-consuming donors. The overall results evidenced an index of elevated nickel levels in the hair of population segment consuming hydrogenated oil, believed to arise from excessive residual nickel in the hydrogenated oil, present at concentrations surpassing the limit recommended by the World Health Organization for the safe ingestion of nickel in food commodities.