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.