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

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.