Adolescence Flashcards
Age of adolescence
Begins at puberty and ends at adulthood; no consensus in age definition
* Early adolescents: 10 to 14 years
* Late adolescents: 15 to 19 years
* Early adulthood: 20 to 24 years
WHO life course model
- Fetal life
- Infancy and childhood
- Adolescence
- Adulthood
Physiological Development of adolescents
Puberty: physical transformation from child to adult and includes
* sexual maturation
* increased rate of gains in height and weight
* completion of skeletal growth
* changes in body composition
Classifications WHO Growth Charts
When does sexual maturation for females begin?
Starts 8 to 12 years of age and process is ~5 years in length
* big height spurt happens first
* menarche usually develops in the middle
* breast usually develops before pubic hair
primary driver of sexual maturation in females
Estrogen
* reproductive organ maturation
* secondary sex characteristics
* menarche (close to middle of puberty)
What are the female tanner stages
sexual maturation rating (SMR)
* breast development
* pubic hair growth
When does sexual maturation for males begin?
Starts 9.5 to 13.5 years of age and process is ~4 years in length
primary driver of sexual maturation in males
Testosterone
* increases testicular volume
* changes to external genitalia
* sperm production
* secondary sex characteristics
Tanner stages for males
Sexual Maturation Rating (SMR)
* genital development
* pubic hair growth
How do the stages of development occur?
Stages of development are consistent,
but duration and timing varies
* nutritional needs based on stage
What mediates increases in weight and height?
Sex hormones and growth hormones mediate increases in weight and height
* gains in bone mass, muscle, organs, blood volume, fat mass (females)
Normal Body Composition Changes in females
peak weight gain after peak height velocity and before menarche of both FM and LM but proportionatly more FM
* gain in fat mass (120%) > lean mass (44%)
* Increased proportion FM and decreased proportion LM
Normal Body Composition Changes in Males
peak weight gain coincides with peak
height velocity (occur together) with increased LM and decreased FM
* decreased proportion FM and increased proportion LM
Why has the age of menarche decreased?
Trend in age of menarche has gone down where it used to be ~13 year but now it is 9-10 year most significantly due to increased BMI associated with earlier puberty in girls
* Leptin is made in adipose tissue and play a role in regulating hormones driving female reproductive cycle which signals that energy stores are adequate for puberty to start
* Permissive signal: removes suppression of GnRH (hypothalamic-pituitary gonadal
axis) iniating menarche`
Role of Leptin in females
related to glutofemoral fat
* increase in leptin precede menarche by about 6 months and remains elevated
leptin in males
increases in leptin precede initiation of puberty, but leptin concentrations then decline
Consequences of very early age of first menses
- social and behavioral impact
- increased risk of: metabolic syndrome/PCOS & breast cancer
Cognitive Development
Switch from concrete to abstract thinking
* Early adolescence: concrete, egocentrism, impulsive behavior
* Middle adolescence: still concrete but starting abstract thinking
* Late adolescence: abstract thinking
Social Development
Starts ~12 years of age and continues until ~24 years of age with development of:
* independence (Getting a vehicle)
* self-identity
* body image
* relationships
* individual beliefs and behaviours related to lifestyle choices
Stages of social development
Early adolescence
* body image and awareness of sexuality
* peer influence strong
Middle Adolescence
* emotional and social independence from family; making decisions for self
* peer influence strongest
Later Adolescence
* personal identity and beliefs
* social confidence, less influence of peers
Early Adulthood
* completion of independence
* adult roles and responsibilities
Nutrition Knowledge
more advanced concepts
* types of nutrients, food sources, recommendations
* link between food choices and health including long term health
food skills
* shopping for food, planning meals, meal prep and cooking, budgeting
What might advanced health knowledge look like?
Able to understand more complex concepts about health behaviours and determinants of health
* advertising and marketing
* socioeconomic
* Empowerment for themselves and others
Role of adults for adolesence nutrition
allow them to have autonomy over their own health and know the consequences
Promotion of Health Behaviours
Messages about health in general directed at adolescents need to take into consideration:
* development: cognitive and social
* behavioural characteristics
* youth culture and trends (coffee, fast food etc.)
Main factors affecting eating behavior
Individual
* biological changes, attitudes, beliefs, preferences, self efficacy
Environment
* Family/home, school, extra-curricular activities, peers, norms
Macrosystems
* Availability, production, distribution, media/advertising, policy
Common eating behaviours
- Eating more meals away from home (schedule, independance)
- snacking (ranges 1-7/d; usually higher in fats, sodium and sugar)
- Meal Skipping (typically breakfast; decreased nutrient dense meal)
Diet Quality
mostly requires improvement or poor quality
* non good quality
Based on recommendations in Eating Well with Canada’s Food Guide
Grain intake
large percentage below minimum serving of grains in females, not so much males
vegetables and fruits intake
Large percentage of both below reccomendations
* females more than males
milk intake
large percent below for milk intake
* females more than males
* Calcium lacking!!
Adolescents – Why Don’t They Eat Healthy Foods?
- Habits of parents modelling
- Marketing/ advertising
- Not cool
- Want to do things havent been able to do
- Lack of availability and not enough variety at the home or school
- Defiance
- Dont realize consequences
Young Adults – Barriers to Healthy Eating
- unhealthy diet of friends and family
- Cheapness and availability of unhealthy foods
- Preference of unhealthy foods
- Lack of time
- Lack of knowledge
- Lack of self-regulation; emotional response
- Lack of motivation
- Risk taking behaviour
Energy Intake Recommendations
Energy needs are higher than that of adults (per kg and absolute) for maintenance, growth and activity and is determined by tanner stage
* Estimated energy expenditure: height, weight, age, physical activity level
* Low intake: impaired growth and delayed sexual maturation
* Excess intake: overweight/obesity
Macronutrient Recommendations
fibre intake stats
Median intake fibre: below AI boys and girls 14-18yrs
Canadian Community Health Survey (CCHS) 2.2 (2004):
AMDRs
What are the micronutrients of concern?
- Vitamin D and vitamin A prominently lacking
- Ca and Mg lacking
- Sodium above upper limit
Why is Ca so important?
Peak Ca accretion rate is highest in adolescence
* females = 12.5 years
* males = 14.0 years
40% of total lifetime bone mass is accumulated during 3-4 years of adolescence
* if calcium intake from foods is inadequate, supplementation (Ca + D) during adolescence can increase bone mineral content
* the more here, the longer it will take to get to fracture zone in later life
Importance of Muscle Mass Accretion
Prevents reaching the disability threshold in later life
Importance of iron
Increased demand for rapid rate of growth which includes increased blood volume
Highest requirement:
* Males: Peak growth rate
* Females: After first menses
Iron DRIs
DRI: accounts for basal loss, maintenance of stores and growth; blood loss in females
* Changers with tanner stage so DRI might depend where you are at in terms of puberty
Reasons why more female adolescents do not meet nutrient recommendations?
- Body image play a huge role
- not eating at home as often
- Skipping breakfast
- Advertised diets of restrictions giving misleading information
- SEM factors
What is poor body image associated with?
dieting behavior, disordered eating and clinical eating disorders. Body satisfaction in Canadian Youth
* over half didn’t like something about body
* Start to go down with age but only slightly
* True for both males and females
Continuum of body image dysmorphia
Body Dissatisfaction
↓
Dieting Behaviors (restrictive behaviours)
↓
Disordered Eating
↓
Clinical Eating Disorders
Clinical Eating Disorders
- Anorexia nervosa (~0.2% to 1% of adolescents)
- Bulimia Nervosa (~1% to 2% of adolescents)
- Binge-Eating Disorder
How to deal with clinical eating disorders
Causes multi-factorial, but prevention has to include the promotion of positive body image and self-esteem
* Thank about all aspects of food eating behaviour
What does Substance Use in Adolescence typically include
- includes tobacco, alcohol, recreational drugs
- for most, experimentation only
Concerns with substance use
nutritional concerns are with chronic or excessive use
* appetite suppression and low intake (alcohol replacing nutrition)
* decreased nutrient absorption and increased losses
* higher requirement of some nutrients
* decreased financial resources for foods
* Smoking would need more vitamin C
Prevalence of Adolescent Pregnancy
Globally, adolescents 15 to 19 years of age give birth to 16 million babies a year (10% of births)
* Canada: 10,600 in 2014 (2.8% of births)
* Rate 3x’s higher in low and middle income
countries: marriage practices, absence of rights, poverty, low education
What are some concerns with adolescence pregnancy?
Increased risk of poor maternal and fetal/infant outcomes since the female is still growing and still has high demand for nutrients for herself, and then requirement during pregnancy creates compounding situation
* mom: maternal mortality, anemia, postpartum weight retention
* baby: stillbirth, neonatal mortality, low birthweight, prematurity
* low rates of breastfeeding
* poor dietary intake (quality, quantity)
Main nutritional issues with adolescent pregnancy
Competition between maternal and fetal growth
* demands for maternal growth (increased height and weight associated with normal development
* demands for pregnancy (maternal and fetal tissues) and lactation
In adolescent the calcium coming from her bone does not not go back on
Nutritional recommendations for adolescent pregnancy
- Same as for pregnancy and lactation in
adulthood but higher energy and some minerals (calcium, phosphorus, magnesium, zinc, iron)
greater need for nutrition support (consult with dietitian, resources)
