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
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Part 2
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Cardiovascular and cancer disease risk
Osteoporosis and bone mineralization
Overweight and obesity
Type 2 diabetes
Eating disorders
Nutritional needs of the adolescent athlete
Adolescents with chronic medical concerns
Adolescent pregnancy
Cardiovascular Disease and
Cancer Risk

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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
 Recommended: <10% of calories from sat fat
and <30% total fat
 Consumed: 1/3 of adolescents are in this range
Sodium
 Recommended: <2.5 g/d
NHANES III data; 8891, McDowell 94
 Consumed: 3-5 g/d
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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

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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)
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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
Buchard 97
heritability of BMI
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
McDowell 94; Kann 99; Troiano 00,
NHANES II to III
PE
sed act
Other Contributors to
Sedentary Lifestyles
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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)
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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 selfesteem (Gortmaker 93), particularly for
females
 Less participation in PE and sports
activities
 Lower college acceptance rates

(Canning 1966)
Health Issues in Overweigt
Adolescents
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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)
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Cardiovascular
Hyperlipidemia-- LDL and TG,  HDL
 Hypertension
 Low frequency in children
 Muscatine Study (Rames 1978)
 1% of 6600 children 5 to 18 had
persistently elevated BP
 60% with  BP were >120% of
IBW
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Type 2 Diabetes
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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 >95th%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
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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)
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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
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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 2nd
decade of life
 40% of which is during adolescence
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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
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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)
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Calcium Content of Foods
Food Item
Milk or yogurt
Cheese
Ca fort OJ
Salmon w bones
Fort. cereal
Broccoli
Orange
1300 mg =
Serving size
1 cup
1 oz
1 cup
3 oz
1 cup
½ cup
1 med
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
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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 Adolescents
Soda/d:
0 oz
.1-13 oz 13-26 oz >26 oz
Calories
1984
2149
2312
2604*
Fat
34 *
32
32
31
239
238
191*
178*
98
100
62*
52*
Calcium mg 819
804
652*
635*
Riboflavin
1.9
1.6*
1.5*
% of kcal
Folate
ug
Vit C mg
* p<.05
2.1
Harnack 99
To Review Risky Adolescent
Nutritional Issues
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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)
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
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Chapman 93
Influences cont
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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)
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 CDROMs

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, 4level team approach to weight
management for adolescents
 http://www.committed-to-kids.com/
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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
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Adolescent Nutrition JADA, March 2002
Stay Tuned for Part 2