Antioxidant effect of zinc supplementation on both plasma and cellular red-ox status markers in a group of elderly Italian population.

OBJECTIVES

The aim of this work was to evaluate the effect of long term supplementation with two moderate dose of Zn on plasma and cellular red-ox status markers in elderly volunteers.

DESIGN, SETTING AND SUBJECTS: In a double blind study 108 healthy volunteers, aged 70-85 years, were enrolled. They were randomly divided in 3 groups of treatment, receiving placebo, 15 mg/day and 30 mg/day of Zn for 6 months. Red-ox status markers were assessed at baseline and after 6 months evaluating carotenoids, vitamin A and E in plasma; glutathione (GSH), thiol groups (RSH), malondialdehyde (MDA), percentage of haemolysis and methemoglobin in erythrocytes.

RESULTS

Zn supplementation had no significant effects on red-ox status markers except for vitamin A levels (from 1.94±0.44 to 2.18±0.48 μM in volunteers receiving 15 mg of Zn and from 1.95±0.46 to 2.26±0.56 μM in volunteers receiving 30 mg of Zn), which increased proportionally to zinc dose.

CONCLUSIONS

It appears that, differently from unhealthy populations, long-term supplementation with two moderate doses of Zn in a healthy elderly population, with an adequate Zn nutritive status and macro and micronutrients intakes in the range of normality, is an inefficient way to increase antioxidant defences.