chapter chapter 15 15 Nutrition and the Nutrition and the Active ActiveFemale Female Prof Jennifer Broxterman, RD, MSc FN3373: Nutrition for Physical Activity Lecture 10 Author name here for Edited books Energy and Nutrient Requirements Weight Maintenance • Female athletes must consume enough kcal to cover energy cost of: – – – – – Daily living Their sport Muscle tissue growth and repair Menstruation and reproductive function Growth (younger females) Females at Risk • Female athletes engaged in aesthetic or lean-build sports with pressure to maintain lean build or competitive weight – Dancers, runners, gymnasts, figure skaters • If weight loss is viewed as a way to improve performance Health Consequences of Chronic Dieting • Chronic dieting or energy restriction can lead to: – – – – Poor energy intake Poor macro and micro nutrient intake Decreased resting metabolic rate (RMR) Decreased total energy expenditure (TEE) Poor energy and macronutrient intake • Almost impossible to get adequate nutrients with energy intake less than 1800 kcal/day – Protein and carbohydrate intake below RDA – Fat intake less than 10-15% of energy intake • Low absorption of fat-soluble vitamins and essential fatty acids • Inadequate protein intake for muscle tissue repair • Inadequate to carbohydrate intake to replenish glycogen • Fatigue, irritability, decreased performance Restore Energy Balance • Increase total daily energy intake (kcal/day) • Decrease total energy expenditure or add “rest day” • Ensure in a state of positive energy balance before beginning any physical activity How Do You Know If an Active Female Is Not Eating Enough? Poor micronutrient intake • Micronutrients of concern: – Calcium and vitamin D: strong bones • More than 90% of total bone mineral density (BMD) occurs by 17 years of age, peeks between 25-30 years – Iron: hemoglobin synthesis, exercise may increase loss of this mineral – Magnesium: building and repairing tissue – Zinc: energy production during exercise – B vitamins: prevent anemia, necessary for energy production Table 15.1 Decreased RMR and TEE • Severe dieting/energy restriction reduces RMR • People who chronically diet have lower total daily energy expenditure Energy restriction + High physical activity fewer kcal required to maintain weight Strategies to maintain a healthy weight • Identify what constitutes a healthy body weight – Genetics, physiological, social, sport, psychological factors Healthy body weight: weight that can be realistically maintained, allows for involvement in physical activity, and reduces risk factors for chronic disease • Must address changes in lifestyle Female Athlete Triad Female Athlete Triad • Interrelationship between: – Energy availability – Menstrual status – Bone health • The disorder can arise through: – Eating disorder (AN, BN, EDNOS) – Disordered eating tendency – Inability to eat enough food • Consequences: – Amenorrhea & reduced bone mineral density (BMD) Figure 15.3 Sports at Risk • Sports that emphasize leanness or a thin body build may place girls/women at risk: – Subjective performance scoring: dance, skating, diving, gymnastics – Endurance sports: long-distance running, cycling, crosscountry skiing – Sports involving body-revealing clothing: gymnastics, swimming, volleyball, aerobics, track, dance, cheerleading – Weight class sports: horse racing, martial arts, wrestling, rowing – Sports emphasizing a preadolescent body build for success: gymnastics, figure skating, diving Real Athletes Real Athletes Real Athletes Real Athletes Real Athletes Low Energy Availability • Low energy availability can be caused by: – – – – Dieting Disordered eating Eating disorder Low energy intake • Low energy availability is the primary factor initiating the disorders of the triad Energy Availability • Definition: – Dietary energy intake minus exercise energy expenditure (EEE) • Need enough energy for basic physiological processes: – cellular maintenance, thermogenesis, immunity, growth, reproduction, and activities of daily living Disordered Eating & Eating Disorders • Eating behaviours form a continuum that can range from normal to clinically diagnosed abnormal behaviours – EDs are diagnosed by meeting criteria outlined by that American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) • Anorexia nervosa (AN) • Bulimia nervosa (BN) • Eating disorders not otherwise specified (EDNOS) • It all starts with a diet… Table 15.2 Anorexia Nervosa • Diagnostic symptoms: 1. Relentless pursuit of thinness and a refusal to maintain a body weight at or above a minimal level. 2. An intense fear of gaining weight or becoming fat. 3. Look at their body differently than healthy individuals and place a high value on a “thin” body type. 4. Amenorrhea is present due to hypothalamic dysfunction, which results from malnutrition. Bulimia Nervosa • Diagnostic symptoms: 1. There is an uncontrolled desire to overeat or binge on food. A “binge” is usually determined on an individual basis. 2. Binge eating must also be characterized by a subjective sense of loss of control. 3. The binge must occur within a discrete time period. • 2x/week for 3 months 4. An individual is highly influenced by body shape and weight in her self-evaluation. Eating Disorders Not Otherwise Specified • Triggering factors for EDNOS: 1. 2. 3. 4. Prolonged periods of dieting. Frequent weight fluctuations. A sudden increase in training volume & intensity. A traumatic stressful event or high levels of stress (e.g. injury, loss of a coach, stressful family event). 5. Pressure placed on the female to maintain or achieve a low body weight. • Sub-clinical eating disorders Menstrual Dysfunction • Diet and exercise can negatively effect reproductive and metabolic hormones – Amenorrhea • Starvation-induced • Exercise-induced – 3 factors contribute to inadequate energy availability in active females: • High energy expenditure • Low energy intake compared to energy expenditure • High psychological and physiological stress, which can reduce energy intake while increasing energy expenditure Common Types of Menstrual Dysfunction in Active Women • Luteal phase defects • Anovulation • Oligomenorrhea • Amenorrhea – Primary amenorrhea – Secondary amenorrhea Factors Contributing to Menstrual Dysfunction • Energy deprivation can alter the hormonal profiles and the menstrual cycle of healthy women • Degree of menstrual dysfunction depends on: – Magnitude of energy restriction – The body’s level of energy reserves – Initial hormonal status before dieting begins • Amenorrhea dietary treatment Bone Health • Loss of bone mineral density (BMD): – Increased risk for osteoporosis – Increased risk for musculoskeletal injuries (stress #) • Primary contributors for loss of BMD: – Low energy intake – Low bone-building nutrients secondary to malnutrition Bone Health • BMD depends on: – – – – – – – – – Current age, age when amenorrhea occurred Length of time an individual has been amenorrheic Current body size and composition Type of exercise engaged in Dietary intakes of bone-building micronutrients Dietary & drug factors that decrease total body Ca levels Total energy intake, level of energy availability Baseline blood cortisol concentrations Genetics Stress Fractures • BMD & stress fractures: – Positive stimulus of exercise on BMD versus – Hormonal and dietary changes associated with menstrual dysfunction = increased risk for # – Risk of stress # was much higher in athletes with menstrual dysfunction (52%) than in their eumenorrheic counterparts (28%) – Jeopardizes a woman’s athletic career and also increases her risk for bone # after menopause Figure 15.5 Warning Signs of the Female Athlete Triad Treatment • Requires a multidisciplinary approach – Sports medicine team, sport dietitian, psychologist, exercise physiologist, coach, trainer, parents, friends of the athlete, and the athlete must work together • Address level of participation in sport • Each team should have a standard procedure for preventing and treating disorders of the female athlete triad • Hormone replacement therapy Treatment: Role of a Sport Dietitian • Weight: – discuss weight hx, CBW, desired BW • Goal of treatment: – help the athlete be lean, fit, healthy, and develop a (+) relationship with food • Anthropometrics: – baseline body composition measurements • Address relationship with food • Estimated nutritional requirements: – kcal, CHO, protein, fat Final Exam Update • Date/Time: Mon. June 23, 2015 @ 1-4pm • Worth: 35% • Will be cumulative (greater emphasis on lectures taught after the midterm) • Format: multiple choice & some true/false • Read lecture notes and textbook chapters (to further your understanding if that helps you study)