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Zinc supplementation does not affect whole-body protein turnover and acute phase protein synthesis in late-middle-aged men

Zinc (Zn) deficiency alters protein metabolism. Inadequate Zn intake has been observed in elderly, whose protein turnover is deregulated. Zinc supplementation could have an effect on protein metabolism in elderly. We determined whether moderate Zn supplementation modifies whole-body protein turnover and albumin and fibrinogen synthesis rates in late-middle-aged men. Three groups of 16 healthy late-middle-aged men received for 6 mo either 0mg.d-1, 15mg.d-1or 30mg.d-1 of supplemental Zn.

At the end of the supplementation period, each subject received an intravenous infusion of L-[1-13C] leucine to quantify whole-body leucine fluxes and synthesis rates of albumin and fibrinogen. In the placebo group, whole-body leucine fluxes to protein synthesis, to oxidation and from protein degradation were 1.46, 0.40 and 1.73µmol.kg.-1min-1, respectively. Zinc supplementation did not change significantly whole-body leucine fluxes. In the placebo group, plasma concentration and fractional rate of protein synthesis were 45g.L-1 and 8.2%.d-1 for albumin and 3.6g.L-1 and 16.7%.d-1 for fibrinogen, respectively. Zinc supplementation did not change significantly this parameter neither absolute rates of synthesis of these proteins. Zinc supplementation did not modify whole-body leucine fluxes neither rates of synthesis of albumin and fibrinogen. It is likely that dietary supply of Zn is sufficient for sustaining whole-body protein metabolism and acute phase protein synthesis rates in the studied population.

Reported by

Equipe Endocrinologie Mitochondriale et Nutrition UMR 866 Différenciation Cellulaire et Croissance
Centre de Recherche de Montpellier 2
34 060 Montpellier Cedex 1 Place Pierre Viala
France