Adequate Energy Intake Prevents Low Bone Mass under Exercise and Low Intake of Nutrients in Young Female Rats

We examined the effects of adequate energy intake on bone strength and bone mass under exercise and low nutrient intake using a rat model of the female athlete triad (FAT).Seven-week-old female rats were divided into four groups: sedentary and ad libitum feeding group (SED), exercise and ad libitum feeding group (EX), exercise and 30% food restriction group (EX-FR), and exercise, 30% food restriction and adequate energy intake group (EX-FR + Ene).Excise groups were performed a voluntary running.The EX-FR + Ene group was fed glucose ad-libitum to adequate energy intake.The experiment lasted for 12 weeks.The energy availability, internal organ weight, bone size, bone strength, bone mass, and calcium absorption in the EX-FR group were significantly lower than those in the EX group.There were no significant differences in these parameters except bone strength in between the EX and EX-FR + Ene groups.The breaking energy in the EX-FR + Ene group was significantly lower than those in the EX group.Our results provide evidence that adequate energy intake is important for optimal bone growth in young female athletes.