Effect of the Energy Intake on the Iron Status of Resistance Exercises Performed in Rats

In many cases, athletes compensate for nutrient deficiencies due to a reduced dietary intake by taking supplements or other means. However, in what ways nutrients are utilized by the body when it is deficient in energy and yet receives adequate amounts of the required nutrients are unclear. We therefore examined the effect of the balance between available energy and iron intake on the iron nutritional status of athletes. The experiment was conducted in two parts. Four-week-old male rats were divided into two groups based on energy and iron sufficiency: Experiment 1 was energy-sufficient and iron-sufficient (ES-FeS) and energy-sufficient and iron-deficient (ES-FeD). Experiment 2 was energy-deficient and iron-sufficient (ED-FeS) and energy-deficient and iron-deficient (ED-FeD) groups. All rats were made to perform climbing exercises 3 days a week at 5 P.M. The results showed that a significantly higher hematocrit, hemoglobin, plasma iron concentration, and TfS were found in the iron-sufficient group than in the iron-deficient group, TIBC was significantly lower in the iron-sufficient group than in the iron-deficient group, and TfS was significantly higher in the iron-sufficient group than in the iron-deficient group, irrespective of energy intake. It was suggested that restricting both iron and energy intake may significantly decrease the amount of iron in the liver and accelerate the metabolic turnover of red blood cells, while restricting iron intake but providing adequate energy intake suggested that resistance exercise-induced tissue iron repartitioning was not altered by iron sufficiency or deficiency.