Influence of dietary fat and zinc supplementation on the iron utilization in growing rats.

BACKGROUND/AIMS: There is increasing evidence that the amount and type of dietary fat may modify the utilization of the trace element iron. The present study investigated the effect of high amounts of fat of different origin at marginal and high dietary zinc supply on the iron utilization.

METHODS

Growing male rats, assigned to 1 of 6 groups of 8 animals each were fed diets that contained either 7 or 100 microg zinc/g. These diets were enriched with 0 or 22% fat as beef tallow (BT) or as sunflower oil (SO) above the basal level of 3% soybean oil. Iron was added as ferrous sulfate at 60 microg/g of diet.

RESULTS

The apparent iron absorption was markedly lower in the case of the high-fat diets at either zinc level. The BT diets resulted in significantly higher iron concentrations in the liver compared to both the SO and control diets. Hemoglobin and hematocrit were not influenced by any of the treatments.

CONCLUSION

Although the high-fat diets reduced iron absorption, there was no evidence for lower iron status parameters in blood and tissues. In contrast, BT as a source of saturated fatty acids markedly elevated liver iron concentrations.