Comparative absorption of zinc picolinate, zinc citrate and zinc gluconate in humans

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Abstract
The comparative absorption of zinc after oral administration of three different complexed forms was studied in 15 healthy human volunteers in a double-blind four-period crossover trial. The individuals were randomly divided into four groups. Each group rotated for four week periods through a random sequence of oral supplementation including: zinc picolinate, zinc citrate, and zinc gluconate (equivalent to 50 mg elemental zinc per day) and placebo. Zinc was measured in hair, urine, erythrocyte and serum before and after each period. At the end of four weeks hair, urine and erythrocyte zinc levels rose significantly (p<0.005, p<0.001, and p<0.001) during zinc picolinate administration. There was no significant change in any of these parameters from zinc gluconate, zinc citrate or placebo administration. There was a small, insignificant rise in serum zinc during zinc picolinate, zinc citrate and placebo supplementation. The results of this study suggest that zinc absorption in humans can be improved by complexing zinc with picolinic acid.