Examining the role of zinc in the elderly
Muscular performance has been shown to reduce with advancing age. Zinc (Zn) has been reported to improve muscular strength because of its participation in the formation of a number of energy metabolising enzymes. Zinc therefore is a protective nutritional component which is vital for older people. Zinc supplementation can have health benefits but excess zinc may interact with iron (Fe) and copper (Cu) metabolism. Since there is still much to be explored regarding muscle strength and Zn status, the ZENITH project conducted a study which aimed to explore the influence of Zn supplementation. Specifically, it examined the correlation between Zn supplementation and muscle strength, physical performance and spontaneous physical activity in an elderly population in Italy. One hundred and eight apparently healthy volunteers consisting of 56 men and 52 women between the ages of 70 and 85 were enrolled. They received a placebo (0 mg) or 15 mg or 30 mg of Zn. Grip strength, knee extension, anthropometry, body composition, performance of the lower extremities and physical activity were evaluated in the beginning, and after three and six months of the supplementation. Results showed that the variables studied at baseline were not significantly different between the supplemented and un-supplemented volunteers. Furthermore, no differences were observed between men and women in regard to mean physical activity level. It is also important to note that improved strength has been associated with improved skeletal muscle and bone mass, but not with physical activity level. Finally, following the six month period of Zn supplementation, no substantial differences were noticed in body composition parameters and muscle strength.
