ABSTRACT Head hair of 150 normal boys from Brazil ranging in age from 1 to 12 years was studied for the influence of color on concentrations of zinc and copper. Hair color was classified visually and also quantified by melanin concentra tion. Visual classification and spectrophotometric measurements of melanin showed good agreement for blond and black colors, whereas large discrepancies were ob served for intermediate colors such as light and dark brown. Hair distributed in four ranges of melanin concentration (the numerical estimate of color) showed no signif icant differences for concentration of Zn and Cu but showed a significantly higher (P < 0.01) concentration for Zn:Cu in black hair than in the other color groups. Correla tion between mineral content (Zn and Cu) and melanin was low and nonsignificant except for Zn in hair color ranging from 0-100 melanin units (r = - 0.34, P < 0.05). Discussion of these findings is presented regarding the importance of hair color change in children and estimation of mineral nutritional status. J. Nutr. 113: 2375-2381, 1983. INDEXING KEY WORDS hair color . melanin . zinc and copper
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Hair as a tool for assessment of body load of minerals has been used in human and ex perimental studies. In human nutritional studies, especially for zinc and copper, head hair has been included. Its inherent charac teristics of ease of collection and storage make it a parameter of choice in elemental (zinc and copper) studies. However, in stud ies of zinc and copper nutrition, hardly any attention has been given to the variations in hair caliber, shape and color, especially in racially heterogeneous populations. In the case of black and white human head hair, the color is determined by the presence or absence of melanin pigmenta tion. As for other colors, like red, a unique pigment has been isolated (1) and reported not to be found in any other color. Whether or not other pigments are present in human hair, is still awaiting confirmation. How ever, in animals, according to Pawelek and KÃ¶rner(2), the five basic colors of skin and hair are determined by the presence of 2375
eumelanin (black and brown), pheomelanin (red and yellow) and the absence of pigment (white). Melanin, the black pigment present in hair, skin and eye tissues, is the most stud ied pigment. The color of head hair is influ enced primarily by the amount of pigment in the cortex. The shade of the color depends on the size and density of melanin pigments (3). Blond hair contains relatively small amounts of pigments localized especially in the superficial layers of the cortex in the form of granules. Dark hair contains a greater amount of pigment distributed dif fusely in other layers of the cortex as well as in the hair medula. Besides the pigment content, small air spaces and the caliber of the hair shaft also affect the color of the hair (3). Dokladal (3) summarizes the speculaÂ© 1983 American Institute of Nutrition. Received for publication 6 May 1983. 'Supported in part by Capes-Fulbright and World Food Institute (ISU). 'Present address: Biochemistry and Biophysics Department, Iowa State University, Ames, IA 50011.
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tions of other authors on additional factors that influence the different types of hair. The color of head hair in the healthy in dividual changes during a lifetime. In melanoderms and xanthoderms the changes are from black hair to white hair in old age. For whites, however, not only do there exist many different colors, but also during growth there are changes in shades (3). The color of head hair in the first 10 years of life was studied by DoklÃ¡dal (3). His find ings indicate that "at and after...