Basic nutritional investigationDietary iron supplements may affect stress adaptation and aggravate stress hyperglycemia in a rat model of psychological stress

ObjectiveIron supplementation is believed to decrease the risk of iron-deficiency anemia or low birth weight. In modern society, a majority of people are in a continual state of stress. Stress-induced hyperglycemia, known as transient hyperglycemia, may be a risk factor causing diabetes. To understand the role of iron in people under stress, it is necessary to evaluate the effect of iron supplementation on glucose or stress hyperglycemia.MethodsThe effect of a diet containing non-heme iron (80 or 320 mg/kg) on Sprague-Dawley rats and those under psychological stress was evaluated.ResultsCompared with control rats, a high-iron diet (320 mg/kg) increased blood glucose transiently in normal rats but induced hyperglycemia persistently in stressed rats throughout the experiment. Iron supplements further aggravated iron deposition and oxidative stress injury to the liver induced by the stress exposure. Glucose-related stress hormones were also affected by iron supplementation in stressed rats.ConclusionOxidative stress may be one of the main reasons for insulin resistance. Moreover, changes in stress hormones indicate that high-iron supplements may affect stress adaptation. Both are primary reasons for the hyperglycemia induced by iron supplementation in stressed rats. Gaining an insight into the mechanisms and correlations of these changes may be beneficial to human health and is important for the prevention of pathologic glycemia-related diseases.