Adolescent Nutrition: Conditions and Interventions PDF

Adolescent 15 CHAPTER Nutrition:...

Adolescent 15 CHAPTER Nutrition: Conditions and Interventions LEARNING OBJECTIVES After studying the materials in this chapter, you should be able to: Prepared by 15.1 Describe at least five chronic health issues that are Jamie Stang considered comorbid conditions of adolescent obesity, including the proposed mechanisms by which obesity raises the risk for these conditions. 15.2 Determine the unique energy, protein, and micronutrient needs of competitive adolescent athletes who have not yet 15.4 Differentiate between disordered eating behaviors and completed growth and development. eating disorders based on frequency and severity of 15.3 Compare and contrast national dietary recommendations symptoms and anticipated outcomes. to prevent and treat hypertension and hyperlipidemia in adolescents. OLJ Studio/Shutterstock.com 378 Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.  Chapter 15: Adolescent Nutrition 379 Introduction Data from the 20 09 –2010 National Health and Nutrition Examination Survey (NHANES) suggest that Multiple factors influence the nutritional needs and behavi- 34 percent of U.S. adolescents are overweight and 18 ors of adolescents. This chapter presents specific nutrition percent are obese. 3 Table 15.1 provides prevalence estim- concerns that affect significant numbers of adolescents, ates of overweight among adolescents in the United States, including overweight, participation in competitive sports, by gender and race/ethnicity. In general, the prevalence substance abuse, eating disorders, hypertension and hyper- of being overweight or obese among females is highest lipidemia. Because overweight, sports participation, and among Black teens, while among males the prevalence is eating disorders affect a larger group of adolescents than highest among Mexican American teens. Data on Amer- other conditions, they are presented in greater detail. ican Indian youth are not available through NHANES or the Youth Risk Behavioral Surveillance (YRBS) survey, but regional surveillance data suggest that 20% of urban Overweight and Obesity American Indian children are obese and 48 percent of American Indian male and 46 percent of American Indian LO 15.1 Describe at least five chronic health issues females between 5 and 17 years olds are overweight or that are considered comorbid conditions of adolescent obese. 3,4 obesity, including the proposed mechanisms by which The persistence of overweight from childhood through- obesity raises the risk for these conditions. out adulthood has not been well quantified. Research The increase in the prevalence of overweight and obesity suggests that the persistence of obesity from infancy to among adolescents has nearly doubled during the past two adulthood increases with age. As many as 90 percent of decades. Exact reasons for this increase have not been identified. Environmental factors, or interactions between genetic and environmental factors, are the most likely causes of the dramatic rise in overweight and obesity. Risk factors for the development of overweight and obesity among children and adoles- cents include having at least one overweight or obese parent; low socioeconomic status; being of African American, Hispanic, or American Indian/Native Alaskan race/ethnicity; and being diagnosed with a chronic or disabling condition that limits mobility.1 Inadequate levels of physical activity and consuming diets high in total calories and added sugars and fats are behavioral risk factors common among a signific- ant proportion of adolescents.2 These environmental factors increase the risk of developing obesity if an adolescent is genetically predisposed to obesity. Weight status among adolescents should be assessed by calculating body mass index (BMI). BMI is calculated by dividing a person’s weight (kg) by his or her height 2 (m 2). The Centers for Disease Control and Prevention has an online BMI calculator (available at http://nccd.cdc.gov /dnpabmi/Calculator.aspx) that can be used to quickly and accurately calculate BMI values for youth. BM I values are compared to age- and gender-appropriate percentiles to determine the ap- propriateness of the individual’s weight for height. Youth with BMI values greater than the 85th but lower than the 95th percentile are considered overweight; those with BMI values above the 95th percentile are considered obese. 2 Growth curves based on BMI values for children and adolescents are available from the National Center for Health ILLUSTRATION 15.1 CDC Growth Charts: United States. Statistics. An example of a BMI growth curve is Developed by the National Center for Health Statistics in collaboration with the National shown in Illustration 15.1. Center for Chronic Disease Prevention and Health Promotion, 2000. Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 380 Nutrition Through the Life Cycle TABLE 15.1 Prevalence of at-risk-for overweight and of obesity and chronic disease risk among youth suggest overweight by race and gender among an increased risk of morbidity and premature mortality 12- to 19-year-olds in NHANES 2009–2010 from coronary heart disease, stroke, diabetes, asthma, and OVERWEIGHT OBESE hypertension among adults who were overweight or obese during adolescence.7 Males White 32.2 17.5 Black 37.4 22.6 Assessment and Treatment of Adolescent Hispanic 42.9 23.9 Overweight and Obesity Male Total 34.6 19.6 Females All adolescents should be screened for appropriateness of White 27.6 14.7 weight-for-height on a yearly basis, or more frequently if Black 45.1 24.8 concerns about excessive weight gain are present. Teens Hispanic 41.9 19.8 with multiple risk factors for obesity require an in-depth Female Total 32.6 17.1 medical assessment to diagnose potential co-morbid com- plications. 2 Illustration 15.2 provides recommended !"#$%&: All data taken from Ogden, CL, Carroll MD, Kit, BK, Flegal, KM. Prevalence of Obesity and Trends in Body Mass Index in U.S. Children and screening and referral procedures for adolescents with a Adolescents, 1999–2010. JAMA 2012; 307(5): 483–490. BMI 85th percentile for age and gender. National guidelines for the treatment of child and ad- overweight adolescents can be expected to remain over- olescent overweight and obesity recommend a staged care weight into adulthood. 5 Identification of overweight at an process based on BMI, co-morbid conditions, age, and early age is important, as research data suggest that chil- progress with previous stages of treatment. 8 Adolescents dren with BMI above the 85th percentile are more than advance through the stages based on age, biological de- twice as likely as children with BMI below the 50th per- velopment, presence of co-morbid conditions, and success centile to continue to gain weight and reach overweight with previous stages of treatment (see Table 15.2). A brief status by adolescence.1,5 The risk of persistence of obesity overview of the stages is included below. from childhood into adulthood increases if at least one parent is overweight. 5 The risk of persistence of overweight Stage 1: Prevention Plus Adolescents with BMI of 85th is also higher among the most overweight individuals, but 85th but < 94th percentile, > 85th but < 94th percentile, with risk factors > 85th but < 94th percentile, with risk factors Fasting lipid levels with risk factors Fasting lipid levels AST and ALT Fasting lipid levels AST and ALT Fasting glucose level Fasting glucose level Microalbumin ILLUSTRATION 15.2 Primary care assessments based on adolescent BMI. © Cengage Learning Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.  Chapter 15: Adolescent Nutrition 381 TABLE 15.2 How BMI is calculated and interpreted for children and teens Calculating and interpreting BMI using the BMI Percentile Calculator involves the following steps: 1. Before calculating BMI, obtain accurate height and weight measurements. See Measuring Children’s Height and Weight Accurately At Home. (www.cdc.gov/healthyweight/assessing/bmi/childrens_bmi/about_childrens_bmi.html) 2. Calculate the BMI and percentile using the Child and Teen BMI Calculator (http://nccd.cdc.gov/dnpabmi/Calculator.aspx). The BMI number is calculated using standard formulas (www.cdc.gov/healthyweight/assessing/bmi/childrens_bmi/about_childrens _bmi.html). 3. Review the calculated BMI-for-age percentile and results. The BMI-for-age percentile is used to interpret the BMI number because BMI is both age-and sex-specific for children and teens. These criteria are different from those used to interpret BMI for adults— which do not take into account age or sex. Age and sex are considered for children and teens for two reasons: The amount of body fat changes with age. (BMI for children and teens is often referred to as BMI-for-age.) The amount of body fat differs between girls and boys. The CDC BMI-for-age growth charts for girls and boys (www.cdc.gov/growthcharts) take into account these differences and allow translation of a BMI number into a percentile for a child’s or teen’s sex and age. 4. Find the weight status category for the calculated BMI-for-age percentile as shown in the following chart. These categories are based on expert committee recommendations. Weight Status Category Percentile Range Underweight Less than the 5th percentile Healthy weight 5th percentile to less than the 85th percentile Overweight 85th to less than the 95th percentile Obese Equal to or greater than the 95th percentile The CDC BMI-for-age growth charts are available at: CDC Growth Charts: United States (hht://www.cdc.gov.nchs/about/major /nhanes/growthcharts/charts.htm). !"#$%&: Centers for Disease Control and Prevention, from http://www.cdc.gov/healthyweight/assessing/bmi/childrens_bmi/about_childrens_bmi.html#How%20 is%20BMI%20calculated. Stage 1 include the importance of daily breakfast consump- with significant co-morbidities. Monthly follow-up and tion, limiting take-out and restaurant meals (including fast assessment of progress is suggested. food), participating in family meals at least 5 times per week, and encouraging youth to self-regulate their intake. Stage 1 Stage 3: Comprehensive Multidisciplinary Intervention treatment can be provided by a single healthcare provider, Stage 3 targets the same behavioral goals as Stage 2, but including physicians, nurses, physician assistants, nurse does so in a more structured, multidisciplinary format practitioners, dietitians, and other allied healthcare pro- with more frequent client contact. This treatment stage is viders who have training in pediatric weight management.8 provided by a team of healthcare professionals who spe- cialize in pediatric obesity management. A detailed eating Stage 2: Structured Weight Management The second and physical activity plan that is designed to lead to negat- stage of pediatric weight management addresses the same ive caloric balance is implemented in this phase.8 A struc- behaviors as Stage 1, but does so in a more structured tured behavior-modification program is recommended, manner. Monitoring of food and nutrition behaviors by with weekly visits for at least 8–12 weeks followed by bi- the adolescent and/or their parent(s) is a key component of monthly or more frequent contact with the adolescent and this stage.8 All of the goals of Stage 1 should be reinforced, his or her family. The recommended membership of the but several are modified in Stage 2. Screen time is limited multidisciplinary team includes a physician, physician as- to < 1 hour per day in this stage, and a meal plan is intro- sistant or pediatric nurse practitioner; a behavioral health duced to emphasize nutrient-dense food choices while min- specialist, social worker, or mental health counselor; a re- imizing energy-dense foods. Journals or log books may be gistered dietitian; an exercise physiologist or physical ther- provided for monitoring target behaviors. Achievement of apist; and a nurse. goals should be rewarded with nonfood items such as new clothing or jewelry or tickets to a concert or event.8 Stage 4: Tertiary Care Intervention The use of Stage 4 Stage 2 can be offered by a health care provider with treatment is appropriate with severely obese teens or those training in behavioral pediatric weight management. Skills who have significant, chronic co-morbid conditions that required to successfully implement this stage of treatment necessitate intensive intervention. 8 Adolescents should include motivational counseling, monitoring and rein- be evaluated for their level of maturity to be sure they forcement, and family conflict resolution. 8 Referrals for are able to understand the high level of commitment re- physical therapy, mental health counseling, and medical quired as well as the potential risks associated with Stage 4 nutrition therapy may be necessary for some adolescents treatment. This level of treatment is provided through a Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 382 Nutrition Through the Life Cycle tertiary weight management center that specializes in ad- to reductions in fat soluble vitamin absorption. Results of olescent obesity; access to these programs may be limited trials with orlistat on improvements in weight status, in- outside of large metropolitan areas. In addition to diet sulin sensitivity and lipid profiles are mixed.10 While some and activity counseling and behavior modification, more trials have shown significant differences in weight loss intensive treatments such as meal replacement, a very-low- among teens who took orlistat while implementing lifestyle energy diet, medication, and surgery may be implemented. (diet and physical activity) changes, others have shown no These treatments are particularly warranted when mul- differences and have attributed weight loss primarily to tiple co-morbid conditions or potentially life-threatening the lifestyle changes.10 Long-term follow-up data on the conditions such as pseudotumor cerebri occur. effectiveness of orlistat on weight status is lacking. Few data on the effectiveness of very-low-energy diets Metformin, a drug commonly used to address insulin or meal replacements are available; however, these meas- resistance and diabetes, is often used as an off-label ures appear to be safely used for short periods of time. 8 (non-FDA approved) treatment for obesity in youth over The use of very-low-calorie diets or protein-sparing mod- 10' years of age.10 Metformin reduces hepatic glucose ified fasts should only be done under continuous medical production, reduces glucose absorption by the intestines, supervision, as these diets have been associated with many increases insulin sensitivity, inhibits fat cell formation and health risks, including orthostatic hypotension, diarrhea, may reduce food intake.10 Data from clinical trials suggests hyperuricemia, cholelithiasis, electrolyte imbalance, and that metformin improves weight loss and glucose control reduced serum protein levels.9 The use of these diets should over lifestyle changes alone, however results varied among not exceed 12 weeks in duration. studies based on initial degree of insulin sensitivity and racial/ethnic background. Weight Loss Medication There is currently only one medication that have been FDA-approved for use by ad- Surgical Weight Loss Gastric bypass has been used for olescents: orlistat, an pancreatic lipase inhibitor that several decades to treat severely obese adolescents who causes fat malabsorption.10 Approved for use by youth were not successful with behavior modification and life- 12'years and older, side effects include steatorrhea, flat- style changes. Guidelines for the use of bariatric surgery ulence, fecal incontinence, and fat-soluble vitamin defi- among adolescents have been published (Table 15.3).11,12 ciencies.10 The gastrointestinal side effects may be reduced In order to be considered as a candidate for bariatric among adolescents who successfully follow a low-fat diet. surgery, adolescents must have a BMI of >35 with med- The use of a multivitamin supplement is recommended due ical major complications or a BMI of >40 with minor TABLE 15.3 Recommendations for consideration of bariatric surgery in adolescents Failure to obtain adequate weight loss after minimum of 6 months of intensive weight loss program participation. SMR/Tanner is at stage IV or higher or 95% of adult physical maturity. BMI 35 with major medical co-morbidities or 40 with mild comorbidities. Strong indications for bariatric surgery in adolescents include major comorbidities, including: type 2 diabetes moderate to severe obstructive sleep apnea Nonalcoholic fatty liver disease Pseudotumor cerebri Mild comorbid conditions that may indicate a need for bariatric surgery include: mild obstructive sleep apnea mild nonalcoholic fatty liver disease hypertension dyslipidemia significantly impaired quality of life Candidate participates in psychological and medical counseling before surgery with agreement to continue counseling after surgery. Candidate must have adequate support of family and a home environment conducive to long-term dietary change. Candidate has the capability to follow medical nutrition therapy protocol after surgery. Candidate agrees to prevent pregnancy for at least 1 year after surgery. Roux-en-Y gastric bypass should be considered safe and effective. Adjustable gastric banding and laparoscopic sleeve gastrectomy should be considered investigative and are not currently approved for use among adolescents in the United States by the FDA. Biliopancreatic diversion and duodenal switch surgical procedures are not recommended in adolescents due to the risk of malnutrition and potential effects on growth, development, and reproductive outcomes. !"#$%&!: Based on American Pediatric Surgical Association Clinical Task Force on Bariatric Surgery 2004; Pratt, J. S. A., Lenders, C. M., Dionne, E. A., et al. 2009. Best practice updates for pediatric/adolescent weight loss surgery. Obesity 17: 901–910; Ibele, A. R., Mattar, S. G. 2011. Adolescent bariatric surgery. Surg Clin N Am 91: 1339–1351. Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.  Chapter 15: Adolescent Nutrition 383 co-morbidities. In addition, teens should have completed deficiency, increasing energy, building muscle, and losing the majority of their adolescent growth spurt before un- weight. National data suggest that more than 28% of dergoing bariatric surgery in order to minimize poten- adolescents consume vitamin/mineral supplements, while tial side effects such as stunting of growth. Once the studies in Canada show a prevalence of vitamin/mineral adolescent growth spurt is completed, nutrient needs are use of 43 percent.16,17 More than half of adolescents who reduced, so it is less likely that nutrient deficiencies will report using vitamin/mineral supplements take them occur among adolescents who have limited food intakes occasionally, with slightly less than half using them daily. following bariatric surgery. The two most commonly per- Approximately half of vitamin /mineral supplements formed procedures for adolescents in the United States consumed by adolescents are multivitamins without are the adjustable gastric band and the Roux-en-Y gast- minerals, 34 percent are individual vitamins or minerals, ric bypass procedures, though the adjustable gastric band 18' percent a re mu lt iv it a m i ns w it h m i nera ls , a nd has not been approved by the FDA for use in individuals 17' percent are iron with vitamin C tablets.17–19 Among under 18 years of age.12 Sleeve gastrectomy is a surgical the individual nutrient supplements used, vitamin C is the option that some bariatric surgery centers are offering to most common, followed by calcium, iron, vitamin E, and extremely obese adolescents. B-vitamin complex.18,19 T he long-term success rate of bariatric surger y Data on demographic differences in adolescent sup- among teens is not well established. Research suggests plement use are apparent; supplement use is directly that adolescents had an mean estimated weight loss of correlated with household income, high food- security 15' percent to 87 percent following bariatric surgery.11 status, having some form of health insurance, and Complications occur in up to 27 percent or more of parental education.16 –19 Adolescents who take vitamin/ patients; however, mortality is rare.11 A meta-analysis of mineral supplements tend to consume a more nutrition- adjustable gastric banding outcomes among adolescents ally adequate diet than those who don’t.16,18-19 Supple- suggests that 8'percent of teens experience complica- ment use is also directly correlated with health behaviors tions requiring further surgery, with the most common such as meeting physical activity goals, consuming more issue being band slippage.13 Iron deficiency was noted in fruits and vegetables, and spending less than 2 hours per 2 percent of adolescents following gastric banding.13 A day watching television, playing video games, or using a study of one-year outcomes following bariatric surgery computer. BMI status and intakes of total and saturated among adolescents found that two of the 30 patients fat and cholesterol are negatively correlated with supple- began regaining weight within the first year follow- ment use. ing surgery, with one adolescent regaining more than Few data are available to quantify the use of non- 50'percent of lost body weight.14 nutritional supplements such as herbs (including herbal Detailed recommendations for pre- and post- operative weight-loss products) among adolescents. Data suggest nutrition recommendations specific to adolescents have that as many as 29 percent of U.S. teens may use herbal been published.15 The post-operative diet is high in protein products.19,20 A study of 353 teens from Canada found and modest in fat content to preserve lean body mass. that 4 percent of adolescents used herbal weight-control Sugars and simple carbohydrates should be avoided or products, 6 percent used energizers (e.g., bee pollen), severely limited to reduce the risk of diarrhea secondary 2'percent used L-carnitine, and 5 percent used creatine.17 to high osmolarity.15 Supplementation with multivit- Adolescents who use herbal supplements have been found amin/mineral preparations following bariatric surgery is to be more likely to engage in health-compromising beha- imperative for adolescents. While all nutrients may require viors, such as the use of cigarettes, marijuana, alcohol, and supplementation when food intake is severely limited other street drugs. 20 following surgery, nutrients that are particularly import- The use of herbs and supplements by youth is highly ant to assess and monitor include: protein; iron; calcium; controversial. Adolescents may take herbal supplements vitamins D, B 6 , B12; thiamin; and folic acid.13–15 The risk for several reasons, including weight loss, treatment of of dehydration is elevated following bariatric surgery due attention deficit disorder, and to increase energy and to the restricted stomach capacity as well as nausea and stamina. Youth with special health care needs, such as vomiting, thus fluid intake should be closely monitored. autism spectrum disorders, attention deficit disorder, and cystic fibrosis, may use supplements more frequently than other adolescents. Teens may also use herbal sup- Supplement Use Among plements to help them lose weight, build muscle, or Adolescents improve athletic performance. Studies are needed to de- termine exactly what types of herbal products are used by adolescents, because many herbs are known to have Vitamin/Mineral Supplements potentially dangerous side effects, and few recommend- Supplements may be used by adolescents for a variety ations are available to guide the use of herbs by children of reasons, including improving health, treating iron or adolescents. Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 384 Nutrition Through the Life Cycle Ergogenic Supplements Used by Teens by prescription for the treatment of growth disorders in youth. The extent of illegal use of GH among adolescents Youth Risk Behavior Surveillance (YRBS) system data is unknown. Given the possibility of significant side effects suggest that 3 percent of adolescents report having used in pubescent adolescents undergoing hormonal changes, steroids without medical supervision. 21 Steroid use is steroids or their precursors and GH should not be used by reported more frequently among male (4 percent) than adolescents. female (2 percent) adolescents, and appears to decrease Creatine is sold as a nutritional supplement to increase with age, peaking during ninth grade. 21 Other U.S. data lean body mass. Creatine, formed in the liver and kidney suggest that the use of muscle-enhancing supplements of the human body, can be obtained in more than ad- may be higher, with 6 percent of males and 5 percent of equate amounts from the consumption of meat. Eleven females using them. 22-24 International data suggest that percent or more of adolescent athletes report the use of up to 91' percent of elite adolescent athletes use dietary creatine; however, the prevalence among male athletes has supplements to enhance athletic performance. 23,24 Steroids been found to be as high as 51 percent. 25 Creatine use has and other ergogenic supplements are taken orally, injected, been found to be most prevalent in athletes who are in- or absorbed through transdermal patches. 21, 2 2 The volved with football, gymnastics, hockey, wrestling, and most common sources of ergogenic aids are parents and baseball. Studies of creatine use in adults show mixed coaches. 23 Supplements used by adolescent athletes include results; data on adolescent performance are sparse. 26 It creatine; individual amino acids or protein powders; appears to be of minimal benefit to endurance athletes, dextrose; caffeine; carnitine; anabolic- androgenic ster- and marginal benefit to those involved in short-duration, oids; anabolic steroid precursors, including dehyd- anaerobic, strength-related sports. 26 Side effects of creat- roepia nd rosterone (DH E A) a nd a nd rostened ione; ine use, which seem to be dose-related, include abdominal beta-hydroxy-beta-methylbutyrate; growth hormone; pain and cramping, nausea, diarrhea, headache, dehydra- Xenadrine; and ephedra. 21–23 They are most often used tion, reduced renal function, increased tendency toward outside of the direct sport season to avoid detection of use muscle strains, and muscle soreness. 24,25 No available data in situations where urine testing may be used. document the long-term health effects related to creatine Anabolic-androgenic steroids are controlled substances use; however, chronic use may be associated with renal used to increase lean body mass and improve strength. 24 damage. 24–26 Steroids and ergogenic supplements are often taken in 1- to Ephedrine was sold as an over-the-counter supplement 3-month periods and are “stacked” so that the peak dose until 2004, when the FDA banned its sale. While it of one substance may overlap the introduction of another has been proven to increase metabolic rate, no known substance. 24 While the use of steroids and ergogenic aids benefits on athletic performance have been documented. 24 is forbidden by national and NCAA regulations, few Ephedrine was removed from the market due to side effects high school athletic programs test athletes for their use. including cardiac arrhythmia, hypertension, increased risk The use of these steroids has been linked to infertility, of myocardial infarction and cerebral vascular accidents, hypertension, physeal closure, depression, aggression, and and, in extreme cases, death. Ephedrine use has been increased risk of atherosclerosis. 24 reported to be at high as 26 percent among female and DHEA and androstenedione are precursors of testoster- 12'percent among male adolescents. 25 one and estrogen. Androstenedione is also a controlled sub- stance, while DHEA is widely available as a supplement. 24 Naturally produced in the human body by the adrenal glands, DHEA levels fall in humans as age increases. Its re- Nutrition for Adolescent puted effects include reducing body fat, decreasing insulin resistance, increasing immune system function, increasing Athletes LO 15.2 Determine the unique energy, protein, and lean body mass, and decreasing risk of osteoporosis; how- ever, no scientific evidence backs such claims. 24 As steroid micronutrient needs of competitive adolescent athletes precursors, androstenedione and DHEA may induce many who have not yet completed growth and development. of the same side effects as steroids, such as irreversible More than half (54 percent) of U.S. adolescents report gynecomastia (breast enlargement) and prostate enlargement playing on one or more organized sports teams through among males and hirsutism (facial hair) among females.24,25 their school or a community organization. 21 Participation As many as 4 percent of adolescents take androstenedione.25 is higher among male adolescents than female adolescents Growth hormone (GH) has been shown to decrease (60 percent versus 49 percent) and reduces with age. White subcutaneous body fat and may strengthen ligaments and and Black adolescents report participation in organized tendons, resulting in fewer injuires. 24 Side effects of its use sports more often than do Hispanic students. include physeal closure, hyperlipidemia, glucose intoler- High levels of physical activity, combined with growth ance, and myopathy. 24 Few data are available on the use and development, increase adolescents’ needs for energy, of GH by adolescents, as it is a substance available only protein, and select vitamins and minerals. Participation in Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.  Chapter 15: Adolescent Nutrition 385 competitive sports often means an adolescent will particip- calories per day to meet their energy needs. Athletes and ate in intense training and competition during an athletic their parents should be encouraged to monitor weight season. If the athlete competes in several sports, energy stability throughout the sports season. During the sea- and nutrient needs will remain relatively stable throughout son, particularly during intense training phases or at the the year. If an athlete participates in only one sport and beginning of a season, athletes should weigh themselves does not maintain a training routine off-season, energy before and after practice and sporting events. Any change and nutrient needs may fluctuate based on the timing of in body weight during the activity signals a loss of body the sports season. Therefore, adolescents must be assessed water, which could lead to dehydration. Any weight loss for seasonal and yearly physical activity when energy and that is not transient (transient losses are often due to de- nutrient needs are determined. hydration) signifies that the caloric intake is inadequate to The energy and nutrient needs of adolescent athletes support growth and development. A thorough assessment vary widely. Many of the recommendations available are of energy and protein intakes, accompanied by measure- based on needs of young adult athletes or are extrapolated ments of body composition, should be taken when unex- from usual nutrient needs of adolescents. The best method pected weight loss occurs. Protein should supply no more of assessing the nutrient needs of athletes is to begin with than 30 percent of calories in the diet. Groups at risk for general dietary needs based on Sexual Maturation Rating inadequate intake would include athletes who follow ve- (SMR, see Chapter 14), adding additional allowances based gan diets or restrict caloric intake to maintain a particular on the unique needs of the individual and the intensity of weight. When the main sources of protein are plant-based, physical activity he or she engages in. In order to assess additional protein intake may be needed because plant- individual nutrient needs, health care professionals must based sources of protein may be less bioavailable. gather information such as the following: Dietary intakes of athletes should follow the MyPlate What sport(s) does the adolescent engage in, and what recommendations, with the realization that the increased is the duration of the competition season? energy needs of athletes may require them to consume the upper limit of food-group recommendations. Athletes What is the level of competition of the adolescent? should be encouraged to eat a pre-event meal at least two Is'participation recreational, competitive, or elite? to three hours prior to exercise; eating too close to exer- What kind of training does the adolescent engage in? cise may lead to indigestion and physical discomfort. 27,28 The method(s), intensity, and duration of training Table 15.4 provides an overview of meal and snack recom- activities should be noted. mendations for adolescent athletes. Foods that are high in Does the athlete typically sweat profusely or lose body fat, protein, and/or dietary fiber should be avoided for at weight during competition? Weighing before and after least four hours prior to exercise, because they take longer practice and competition is a good idea, especially to digest and may cause physical discomfort during exer- during outdoor activities in hot and humid weather or cise. Protein and fat also displace complex carbohydrates, in cases where gear may cause sweating (e.g., hockey which are the most readily available source of energy goalies). during athletic events. Post-event meals should contain Does the athlete follow a special diet or take supple- approximately 400 – 600 calories and should comprise ments to improve athletic performance? The type, high-carbohydrate foods and adequate amounts of noncaf- amount, and frequency of supplement use should be feinated fluids. 27 noted and counseling provided as necessary. General energy and protein needs are discussed in Calcium Calcium intakes have been shown to be below the Chapter'14. These guidelines should provide the founda- DRIs in a significant proportion of adolescents, especially tion for calculating protein and energy needs for athletes. females. Athletes’ increased risk for bone fractures makes Competitive athletes may require 500–1500 additional adequate calcium intake extremely important. 27 Although TABLE 15.4 Recommendations for food and beverage prior to sports events MEAL/SNACK COMPOSITION TIMING EXAMPLES OF RECOMMENDED FOODS AND BEVERAGES Snack with 15–20 g CHO and