The Effects of Increased Caloric Intake on Reproductive and Bone Health: A Report of Three Cases
Open Access
- Author:
- Riddle, Emily Suzanne
- Area of Honors:
- Kinesiology
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Dr. Mary Jane De Souza, Thesis Supervisor
Stephen Jacob Piazza, Thesis Honors Advisor - Keywords:
- exercise-associated amenorrhea
bone mineral density
menstrual dysfunction
energy deficiency
caloric intake - Abstract:
- Functional hypothalamic amenorrhea (FHA), a menstrual disturbance characterized by the absence of a menstrual cycle for at least 90 days, occurs in response to a chronic energy deficiency and is common among exercising women. When challenged by an energy deficient environment, the body repartitions its energy expenditure away from the processes not necessary for survival, such as growth and reproduction, ultimately leading to menstrual dysfunction and low bone mineral density (BMD). Non-pharmacological treatment strategies to address the energy deficiency and its associated consequences are currently being explored. The purpose of this study was to examine three exercising women with FHA who participated in a 12-month intervention involving an increase in energy intake designed to meet energy expenditure needs, improve energy status, restore menses and improve BMD. Participants were instructed to increase their caloric intake 20-30% above baseline energy requirements. Repeated measures of dietary intake, body weight, body composition and BMD, resting energy expenditure (REE), exercise energy expenditure , exercise volume, and circulating concentrations of energetic (triiodothyronine (TT3), ghrelin, leptin) and reproductive (estrogen, progesterone, luteinizing hormone) hormones and bone markers were collected. The women ranged in age from 19-30 years, weighed 53.2-54.7 kg, and were recreationally active, participating in 4-9 hours of physical activity each week. Duration of amenorrhea prior to the intervention ranged from 90 to 330 days. Daily caloric intake increased between 400-900 kcal/day by month 12 of the intervention. Weight gain averaged 3.2 kg coinciding with an average increase in fat mass and body mass index of 2.2 kg and 1.6 kg/m2, respectively, among the three participants. The women resumed menses 23-74 days into the intervention, and two women ovulated during the first cycle. Markers of energy status (leptin, TT3, REE) increased in all women. A clinically significant increase in lumbar spine BMD of 3.0% was observed in one woman by month 12 of the intervention. This case study report documents the simultaneous changes in energetic and metabolic status and the associated effects on reproductive and bone health in amenorrheic, exercising women undergoing a 12-month intervention of increased caloric intake. Restoration of an optimal energetic environment through an increase in caloric intake may be a promising treatment strategy for recovery of menses among exercising women with FHA.