Adolescent Nutrition

Kathryn Camp, MS, RD, CSP

Topics for Discussion

     Adolescent growth and development Psychosocial development Nutritional issues for adolescents  Acute and chronic disease risk Influences on adolescent eating behaviors Effective nutrition interventions

Adolescence: The Vulnerable Life Stage

 Big changes: Biological  Boys—get tall, lean, and dense (bones, that is)  Attain 15% of final adult ht during puberty  Lean body mass doubles  Large calorie needs—increase from 2,000 at 10 yr to 3,000 at 15 yr

Adolescence: The Vulnerable Life Stage

 Girls—get taller and fatter  % body fat increases from the teens into the mid-20s   Gain almost 50% of their adult ideal weight 6-9 mo before ht rate increases during puberty  Dieting can have a negative impact on linear growth during this time Calorie needs increase by only 200 from 10 yr to 15 yr

 Cognitive  Thinking style changes from concrete to hypothetical and abstract “takes the adolescent beyond the here and now into the realm of possibilities” (David Elkind, 1984)

 Identity development    Attempt to figure out who they are Success is dependent on positive interaction with the environment—home, school, and the community They will “try on” different lifestyles looking for the “right fit”  Risk taking behaviors—alcohol, drugs, tobacco, sexual behaviors, self-injury and suicide • Immediate and severe consequences

Behaviors with Less Pronounced Consequences

    Eating choices Physical activity and exercise Affect adolescents’ sense of well-being, energy and health in the short term Affect adult-onset chronic disease risk in the long term

Another form of Risk-Taking Behavior

Nutrition Issues in Adolescent Health

     Cardiovascular and cancer disease risk Osteoporosis and bone mineralization Overweight and obesity Type 2 diabetes Eating disorders Part 2    Nutritional needs of the adolescent athlete Adolescents with chronic medical concerns Adolescent pregnancy

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Cardiovascular Disease and Cancer Risk

One-third of CVD and cancer-related morbidity attributed to dietary patterns  Diets high in sat fat, total fat, and sodium and low in fiber  Diets low in fruits and vegetables Dietary fat   Sodium  Recommended: <2.5 g/d  Recommended: <10% of calories from sat fat and <30% total fat Consumed: 1/3 of adolescents are in this range Consumed: 3-5 g/d NHANES III data; 88 91, McDowell 94

  Fiber  Recommended: Age + 5  Consume: ½ this amount Fruits and vegetables  high in fiber and low in fat and sodium  the least consumed food groups for teens  1/4 eat 2 or more servings of fruit/d  <25% eat at least 5 servings of fruits and vegetables daily Munoz 97, Kennedy 95

Food Ingestion: # 1 on Mom’s ddx

Eating Away from Home    Teens directly spend more than   $5.4 billion in fast food restaurants $9.6 billion in food and snack stores  $736 million in vending machines  78% in school Fast foods tend to be low in Fe, Ca, riboflavin, vitamin C, and folic acid More meals missed at home thus the choice of foods away is more important than the time or place

Frequency of Fast Food Restaurant Use Among Adolescents (French 01)    Positively associated with  Total kcal, % kcal from fat, daily servings of soda, cheeseburgers, french fries and pizza  Student employment, TV watching, home availability of unhealthy foods Negatively associated with  Daily servings of fruit, vegs, milk  Perceived maternal and peer concerns about healthy eating Not associated with overweight status

Overweight, Obesity, and Type 2 Diabetes

Etiology of Obesity

   Heritability Homeostasis Specific syndromes

Heritability

   Survival advantage to conserve energy as fat through human evolution Humans enriched for genes that promote energy intake and storage and minimize expenditure.

Enhance female fertility and ability to breastfeed offspring

  In modern industrial environment  easy access to calorically dense foods  encourages sedentary lifestyle Metabolic consequences of these genes are maladaptive

Genetic Factors account for 20-40% of heritability of BMI Buchard 97 Rankinen 02  34 single gene mutations in 83 individuals reported by 2001  > 250 susceptibility genes linked with human obesity phenotypes Familial Risk: 2-3 fold for moderate obesity 5-8 fold for severe obesity Bouchard 01

Obesity Associated Syndromes and Conditions

Overweight Prevalence Increasing

Overweight tracks into Adulthood

 Overweight teenagers are 4-5 times as likely to be obese adults ( Guo and Chumlea 99)

35 4 3 36 37 BMIs of the University of Miami Blocking Machine 39 38

Causes of Marked Increase in Overweight

 Reflects a shift towards positive energy balance

energy intake

= energy expenditure 100-300 kcal/d PE sed act McDowell 94; Kann 99; Troiano 00, NHANES II to III

Other Contributors to Sedentary Lifestyles

    Video and computer games Parental work schedules Unsafe neighborhoods • discourage parents from allowing children to play outdoors • force parents to drive children to school Lack of recreational facilities in low-income neighborhoods

Prevalence of Overeating Among 4,746 Adolescents (Ackard 03)   17.3% of girls and 7.8% of boys reported overeating and were more likely to:  be overweight or obese  have dieted in the past year  be currently trying to lose wt Those who met the criteria for binge eating syndrome (3% of girls and 1% of boys) had higher suicide risk (28% for girls and boys)

Psychological and Economic Consequences of Adolescent Obesity    Discrimination, rejection and low self esteem (Gortmaker 93), particularly for females Less participation in PE and sports activities Lower college acceptance rates (Canning 1966)

Health Issues in Overweigt Adolescents

 Growth  Taller, advanced bone age, mature earlier  Early maturation is associated with  increased fatness and truncal fat distribution in adulthood

   Hepatic Steatosis Orthopedic Problems Sleep Apnea  Occurs in 17% of obese children and teens (Marcus 1996)  Deficits in learning, memory, and vocabulary (Rhodes 1995)  Obesity hypoventilation syndrome (rare, potentially fatal disorder)

Cardiovascular

  Hyperlipidemia-  Hypertension   LDL and TG,  Low frequency in children Muscatine Study (Rames 1978) HDL   1% of 6600 children 5 to 18 had persistently elevated BP 60% with  IBW BP were >120% of

Type 2 Diabetes

     3-10 fold increase in prevalence in adolescents Mean age is 13.5 yrs 95% of teens with Type 2 diabetes have a BMI >85%ile  increased insulin resistance 21% of adolescents with BMI’s >95 th %ile had impaired glucose tolerance (Rocchini 02) Tremendous public health implications  Longer duration of disease, > risks of complications Dabelea 99; Vinicor 00; Richards 85

How Do Teens Attempt to Lose Weight?

 1999 Youth Risk Behavior Surveillance  58% exercised  40% ate less food or lower fat foods  13% fasted  8% took diet pills  5% vomited or took laxatives Kann 1999

Weight-Related Eating Disorders

 Anorexia nervosa  Self-starvation, weight loss, intense fear of weight gain, body image distortion

 Bulimia nervosa  Binge eating and purging  Binge eating disorder  Binge eating without purging resulting in weight gain

Anorexic and Bulemic Behaviors

   Expressed in 10-20% of adolescent girls Mimic behaviors in AN and BN but are not done with the frequency or severity to classify as mental illness Half of teen girls and 15% of boys report dieting behaviors  Ranging from eating less fat to fasting (Neumark-Sztainer 00)

Osteoporosis and Bone Mineralization

  Osteoporosis affects 25-30 million adults in the US, women > men  15-25% with hip fractures require long-term institutional care  Treatment of osteoporosis costs $14 billion/yr Etiology complex—genetic, hormonal, physical activity, dietary factors

  Maximum peak bone mass (PBM) at skeletal maturity is protective PBM is achieved during the late stage of pubertal development  90-95% of PBM is attained by the 2 nd decade of life  40% of which is during adolescence

  Low bone mineral density is associated with fractures late in life Adequate nutrition, including energy, protein, vitamins and minerals are associated with good bone health

Calcium

    Milk and dairy products are primary source of calcium in the US Only 49% of boys and 20% of girls consume the recommended number of servings from the dairy group.

AI for calcium for 9-18 yr is 1300 mg/d Girls 14-18 yrs consume 55% of this goal at 713 mg  42 mg/d (Grove 98)

Calcium Content of Foods

Food Item

Milk or yogurt Broccoli Orange

Serving size

1 cup Cheese Ca fort OJ 1 oz 1 cup Salmon w bones 3 oz Fort. cereal 1 cup ½ cup 1 med 1300 mg =

Mg calcium

300 175-275 200-300 180 100 47 40 3 cups milk; 1 oz cheese, ½ c broccoli, 1 orange, 1 c cereal

Soda Consumption: Effects on body weight, dental health and nutritional status    No association with dental caries (Heller 01) 25% of adolescents drink >26 oz of soda/d Inverse relationship between intake of nutrients found in milk and fruit juice with soda consumption  Riboflavin, vitamin A, calcium, phosphorus, and vitamin C ( Harnack 99)

Mean Nutrient Intake by Level of Soft Drink Consumption in

A

dolescents Soda/d: Calories Fat % of kcal 0 oz 1984 34 * Folate ug Vit C mg Calcium mg 239 98 819 Riboflavin 2.1

* p<.05

.1-13 oz 13-26 oz >26 oz 2149 32 2312 32 2604 31 * 238 100 804 1.9

191 * 62 * 652 1.6

* * 178 * 52 * 635 1.5

* * Harnack 99

To Review Risky Adolescent Nutritional Issues

    Weight gain leading to obesity and type 2 diabetes Calcium intake and soft drink consumption leading to inadequate bone mineralization Eating habits that result in disordered eating practices Low consumption of fruit and vegetables and high consumption of fat and sodium are related to adult-onset disease risk

“The relationship between the adolescent diet and chronic disease risk is predicated on the assumption that eating behaviors are learned and solidified during childhood and adolescence and are maintained into adulthood” (Lytle 02)

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What Influences Adolescents Food Choices?

Psychosocial   Strong Influences  Food preferences • Early childhood experiences, exposure, genetics  Taste and appearance Weak influence  Health and nutrition • Only 26% of college students were motivated by health when making dietary choices (Horacek 98)

The Meaning of Food

   Study of 93 Canadian adolescent girls Eating “Junk food” was associated with pleasure, being with friends, weight gain, independence, guilt, affordability, and convenience.

Eating “healthful food” was associated with family, meals, and being at home Chapman 93

Influences cont

  Biological  “I was hungry” is often the first response when asked why a specific food was eaten Lifestyle  Time and convenience   Teens would rather sleep than eat breakfast (Neumark 99) Cost  In a study of 12 high schools, consumption of fresh fruits and vegs  when cost was  by 50% (French 01)

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More Influences

Family—major influence   Food provider Influences food attitudes, preferences and values   Despite increased eating outside the home, teens still obtain 65% of their total energy from home.

Dinner at home is the most important meal   80% of parents and teens place high importance on this meal 1/3 of teens eat dinner q night at home

Effective Nutrition Interventions for Adolescents

     Behaviorally based Use developmentally appropriate strategies Include an environmental component Sufficient amount of contact Use technological advances such as CD ROMs Hoelscher, JADA 2002;102:S52

Nutrition Intervention Programs for Adolescents

  Clueless in the Mall: An interactive web site on calcium for teens  Texas Cooperative Extension Service  http://calcium.tamu.edu/ Committed to Kids: An integrated, 4 level team approach to weight management for adolescents  http://www.committed-to-kids.com/

  Great Beginnings: Nutrition curriculum for pregnant adolescents   University of New Hampshire http://ceinfo.unh.edu/Common/Docu ments/grtbegin.htm

Gimme 5: A school-based nutrition intervention for high school students  Baylor College of Medicine Adolescent Nutrition JADA, March 2002

Stay Tuned for Part 2