Low‐abundance plasma protein differences between African‐American and Caucasian early pubertal females following supplementation with 9 mg Zn (1043.10)

The purpose of this research was to determine whether supplementation with oral zinc levels near the RDA for 4 wks would affect plasma protein levels in African‐American (AA) and Caucasian (C) early pubertal females. The subjects were given either 9 mg elemental zinc (n=75; 40 C, 35 AA) or placebo (n=71; 40 C, 31 AA) to consume for 4 wks. Plasma was collected from subjects at baseline (BL) and 4 wks, and was analyzed for zinc by atomic absorption. Plasma from subjects that were most responsive to zinc supplementation (BL to 4wk; n=5), or exhibited the least difference between BL and 4wk (placebo; n=5) were analyzed. Individual plasma samples were prefractionated on immunoaffinity columns to remove 14 high‐abundant plasma proteins. Effluent proteins were separated by two‐dimensional gel electrophoresis (400 µg; 15% acrylamide 2nd dimension). The gels were stained with Coomassie blue G‐250 and analyzed by densitometry. Significant differences were determined by Student’s t‐test. Comparisons were made between untreated (UnTrt; n=15) vs. zinc‐treated (ZnTrt; n=5) plasma. Two proteins were affected by zinc consumption, 33.8kDa/pI 5.4 (UnTrt C: 0.70±0.11 (SEM), ZnTrt C: 1.56±0.46 (SEM; p=0.02); UnTrt AA: 0.73±0.10 (SEM), ZnTrt AA: 0.64±0.24 (SEM; p=0.67) and 32.4kDA/pI 5.8 (UnTrt C: 1.14±0.22 (SEM), ZnTrt C: 1.58±0.18 (SEM; p=0.16); UnTrt AA: 1.97±0.22(SEM), ZnTrt AA: 1.02±0.28 (SEM; p=0.03). These zinc‐responsive proteins were affected by the race of the supplemented individuals, suggesting there are subtle differences in the zinc metabolism of individuals from different racial or cultural backgrounds. Grant Funding Source : Supported by USDA Hatch GEO00682