Exercising women with menstrual disturbances consume low energy dense foods and beverages


Journal Title (Medline/Pubmed accepted abbreviation):Appl Physiol Nutr Metab Nutrition.
Year: 2011
Volume: 36
Number:
Page numbers: 382-394
doi (if applicable):

Summary of Background and Research Design

Hypothesis:The authors hypothesized that women with exercise-associated menstrual disturbances (EAMD) will consume a diet that is lower in energy density (i.e., kcal per gram food or beverage consumed) than eumenorrheic exercising women. Strategies for lowering energy density include increasing fruit and vegetable intake, lowering fat intake, and consuming a higher amount of noncaloric beverages. The authors further hypothesized that peptide YY (PYY) levels would be higher in EAMD vs. eumenorrheic exercising women [NOTE: PYY is a gut peptide that is associated with decreased food intake.]

Subjects:25 female volunteers who met the following inclusion criteria: age 18-35 y; body mass index (BMI) 16-25 kg/m2; body fat ≤30%;no history of current or chronic illness; stable weight (±2 kg) for the previous 6 mo.; nonsmokers; no medications that would alter metabolic hormone concentrations; no menses in the previous 3 months or 6 or fewer menses in the previous 12 months (EAMD),regular menses in the previous 6 months (ovulatory, or OV); no history of polycystic ovarian syndrome or a free androgen index  ≥3 with other diagnostic symptoms of polycystic ovarian syndrome;≥2 h/week of self-reported aerobic or resistance training exercise; nonpregnant/not planning pregnancy; not currently diagnosed with an eating disorder or other clinical psychiatric disorder.

Experimental design:Cross-sectional, observational

Treatments and protocol:Treatments not assigned, observational study

Protocol:Subjects who met inclusion criteria underwent a clinical visit that included anthropometric measures (height, weight, BMI, body composition by dual energy X-ray absorptiometry (DEXA) for measures of fat-free mass (FFM)), a physical exam, a health, exercise, and nutrition survey, the Three-Factor Eating Questionnaire (TFEQ), the Eating Disorder Inventory questionnaire, psychological interview, and blood sampling for complete blood count and endocrine panel. Subjects recorded daily exercise for 7 days and dietary intake was assessed via 2 sets of 3-day food records that were compiled 2 weeks apart. Other variables measured were: energy availability (i.e., energy intake minus energy expenditure divided by FFM (kg)), resting energy expenditure, aerobic capacity (VO2 max), menstrual status, and satiety (as assessed by PYY concentrations in the blood).

Summary of research findings:
  • EAMD women exhibited significantly lower energy intake per kg fat-free mass (37.2 kcal/kg FFM) than OV women (49.6 kcal/kg FFM (P = 0.008)
  • EAMD women had lower resting energy expenditure than OV women (1191 vs. 1316 kcal/day, P = 0.007), which also held true when normalized to energy expended per kg FFM.
  • Energy availability was ~ 32% lower in EAMD vs. OV women.
  • Energy density, including noncaloric beverages, was lower for EAMD women (0.77 kcal/g) versus OV women (1.06 kcal/g) (P = 0.018). When Goldberg criteria were applied to energy intake and energy density (to account for underreporting of food intake), the energy intake and energy density values, while still lower in EMAD vs. OV women, were no longer statistically significant.
  • Fasting PYY levels were higher in EAMD vs. OV women
  • The EMAD women tended to consume more vegetables, fat-free condiments, and noncaloric beverages than the OV women.

Interpretation of findings/Key practice applications:

Women with EMAD exhibited several of the dietary behaviors that the authors hypothesized would be present at a greater prevalence in this population versus women with normal menses. It is likely that the increased use of nonfat condiments allows for greater flavor with more minimal caloric contribution. It would be interesting to see if these behaviors might have predictive value in assessing either eating disorders or athletic amenorrhea. Screening questionnaires might make use of the known increased frequency of these behaviors to help with early detection of either eating disorders or athletic amenorrhea.
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