Iron status, blood lipids and endogenous antioxidants in response to dietary iron levels in male and female rats.

The effect of dietary iron levels on iron status, blood lipids and endogenous antioxidants was investigated in male and female rats. Diets low in iron (15 mg/kg Fe; LFe) or high in iron (400 mg/kg Fe; HFe) were given to groups of male (n = 6) and female (n = 6) weanling rats for six weeks. In a second experiment the same dietary iron levels were fed to groups (n = 12) of males and females for seven months, during which colon tumours were induced. Indices of iron status, blood lipid levels and antioxidant enzyme activities were measured in both experiments. In the first experiment, indices of iron status were significantly higher in HFe rats and in females compared with males. Cholesterol and triglycerides were significantly higher in HFe rats and cholesterol was significantly higher in males. Plasma albumin and bilirubin levels and plasma caeruloplasmin activity were significantly higher in female rats. The second experiment confirmed the higher indices of iron status in HFe rats and in female rats, and also showed that plasma cholesterol levels were significantly higher in HFe rats. There were no consistent, significant differences over both experiments in activities of the antioxidant enzymes measured. Results show that higher dietary iron levels are associated with higher cholesterol levels in male and female rats. However cholesterol was found to be higher in male rats while iron status was higher in female rats. This indicates that factors other than iron status are responsible for the differences in cholesterol in male and female rats.