engleski

INFLUENCE OF HIGH DIETARY IRON ON TOCOPHEROL AND RETINOL CONCENTRATION IN MICE FED OLIVE- AND CORN-OIL ENRICHED DIET

Background. Iron is an essential mineral for growth and development of most organisms but can also play a catalitic role in initiation of free radical reactions. These free radicals potentially damage cellular lipids, proteins and carbohydrates. High content of dietary iron may result with increased lipid peroxidation especially in diet with higher proportion of polyunsaturated fatty acids (PUFAs) but little is known about these interactions. Therefore, the aim of this study was to determine the effect of a high dietary iron on a-tocopherol and retinol status in mice fed olive oil and corn oil supplemented diets. Methods. Male Balb/c mice were divided in five groups and fed for three weeks. The control group was fed a standard rodent diet and the other groups were supplemented with either olive- or con-oil with adequate Fe or excess Fe. Fe levels in liver tissue was determined by inductively coupled plasma spectrometry, fatty acid analysis was done by gas chromatography and vitamin levels were mesured by high-performance liquid chromatography. Results. Both dietary oils and iron increased the liver Fe uptake and changed the liver fatty acid composition. Additionally, high-iron diet induced oxidative stress in mice liver. Liver retinol and tocopherol stores increased with iron supplementation in the olive oil-enriched diet, with a simultaneous decrease in serum. The results suggest that the influx of tocopherol and retinol from serum to the liver is induced by high dietary iron. This redistribution appears to be stronger for retinol than for tocopherol and is also higher in mice fed olive oil than in mice fed corn oil, suggesting that the composition of dietary lipids is important in the treatment of high-iron tissue conditions. Conclusions. The results of this study suggest that the increase of hepatic tocopherol and retinol levels in the olive oil-based diet is a dietary-dependent responsive mechanism that probably is not primarily related to an increase risk of oxidative damage induced by high-iron intake.

iron; olive oil; tocopherol; retinol

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