The effect of iron and zinc supplementation and its discontinuation on liver antioxidant status in rats fed deficient diets

Abstract

Purpose: The aim was to investigate the effect of iron or combined iron/zinc supplementation on rat liver antioxidant status.

Methods: The 6-week male Wistar rats were examined in 3 stages: (1) 4-week adaptation to the diets (C-control AIN-93M diet, D-iron deficient and R-with 50% reduction in all vitamin and mineral amounts); (2) 4-week supplementation with the same regimen enriched with tenfold more iron or iron/zinc; (3) 2-week post-supplementation period (the same diets as in the stage I).

Results: Combined iron/zinc supplementation similarly to iron supplementation alone significantly (p values ≤ 0.05) increased the iron content in the liver in D and R rats after stages II and III. Moreover, iron/zinc supplementation compared to iron supplementation alone significantly decreased the liver concentration of 8-isoprostane (after stage II in D and after stage III in R rats), protein carbonyl groups (only after stage III in R rats) and 8-hydroxy-2-deoxyguanosine (after stage II in R and after stage III in D and R rats). In rats fed R-type of diets after stage II hepatic superoxide dismutase (SOD) and catalase (CAT) activity, but not glutathione peroxidation activity and total antioxidant capacity, was lower in iron and iron/zinc supplemented than in non-supplemented rats, whereas after stage III in iron/zinc supplemented SOD was lower and CAT activity was higher in comparison with non-supplemented and iron supplemented rats.

Conclusions: The simultaneous iron/zinc supplementation can protect liver against peroxidative damage induced by high doses of iron during and after the intervention in rats fed iron-deficient diet and diet with reduced amounts of vitamins and minerals. The post-intervention observation is relevant because the effect may be delayed and visible only after this period.