lecture 7: adolescence Flashcards
what are the key messages from adolescent Nutrition 1 - Nutrition on adolescence growth and development - Lancet series
- Time of transformative growth, both undernutrition and obesity affect multiple
physiological systems - A time of unprecedented change in food environments (e.g., with both micronutrient
deficiencies/food insecurity and obesity) - Intergenerational impacts – a period of growth and development with profound
consequence on individual’s health in later life (and health of any potential children) - Adolescent nutrition affect timing and form of puberty
- Nutrition sensitive window to promote healthy growth and reduce risk of obesity later in
life - Scaling up research is needed as is underinvested
describe adolescent physiological development in terms of height and weight
- Over 1.5 – 3-year time span
- Females – 16cm and 16kg
- Males – 20cm and 20kg
- Average height is increasing (nutrition and health, environments and health of the mother)
- Weight is disproportionally increasing
- Growth charts important in monitoring growth
describe adolescent physiological development in terms of sexual maturation
- Five stages of development (Tanner Stages)
- Useful in further understanding nutrition requirements as peak-velocity growth occurs:
- Stages 2 and 3 for females
- Stage 4 for males
describe adolescent physiological development in terms of body composition
- Males – greater muscle development, and proportionately less fat at ~16-18% (testosterone)
- Females – muscle mass continues to develop, though greater fat deposition at ~ 22-26% (oestrogen)
- Link between overweight and obesity in girls and earlier menstruation
describe adolescent physiological development in terms of body skeletal growth
- Period of rapid bone growth due to impact of sex, thyroid and growth hormones
- Full adult statue reached ~17 years for females and ~21 years for males
- Bones are set and are at their longest (and will not change)
- Bones widen and become denser (and continue to increase in density until up to 30years)
- Over half of adult bone mass is laid down in adolescents
describe early adolescence development
- Adjusting to
developing body - Beginning of the
development of
moral concepts - Friends are a
strong influence,
and family are less
influential - Approach to
improving nutrition
should focus on
the now
describe middle adolescence development
- Increased
emotional
independence
from family - Increase in health
risk behaviors - More comfortable
with developing
body - Some financial
independence
describe late adolescence development
- Physical
development near
completion and
cognitive
development close
to adult-level - Better
understanding of
self, beliefs, values - Employed or
tertiary studies - Approach to
improving nutrition
can focus on link
between present
and future
what are the key messages from Adolescent Nutrition 2 – Food choice in transition
(adolescent autonomy, agency, and the food environment) - lancet series
- Dietary intakes during adolescence – foundation for healthy life
- But adolescents are diverse in their dietary patterns/factors that influence food choice
- Unique contextual features that drive dietary intake and food choice
- More evidence and research needed
- Adolescents must be active partners (autonomy and agency) in shaping action
- Food environments are not conducive to healthy food choice
- Need:
- regulation/policy to improve the food environment
- empowering with knowledge/skills and motivation to navigate to a healthy/socially appealing diet.
individual factors influencing adolescent nutrition and diet
- Adolescent brings significant changes in lifestyle, eating behaviours, exposure to environmental
influences - Impact of:
- personal factors (e.g., body image, level of autonomy, preferences…)
- psychosocial factors (e.g., attitudes, beliefs, self-efficacy, mood, mental health…)
- biological factors (e.g., appetite, hunger, taste..)
- Increased susceptibility to food fads, and restrictive diets can lead to habits of skipping and substituting
meals
social factors influencing adolescent nutrition and diet
- Enhance social interaction can lead to influence of others on their decision making
- Social and emotional importance of peers increases
- Adolescents eat ~ 1/3* of meals away from home, hence nutrition influenced by choices made (*Aust source:
Whitney et al., 2022) - Peer influence occurs both in person and online
environmental factors influencing adolescent nutrition and diet
- Physical, economic, social, cultural, political environments influences on adolescent dietary
behaviour - External environmental factors very influential – hence targeted health promotion messages
may aid in improving adolescent food choices - Consumption of discretionary foods (high sugar, high fat) is higher outside of the home e.g.,
school vending machines, retail food outlets, online food delivery apps and services - Adolescent exposure to food messaging and marketing e.g., both physical food environment
and online space (e.g., peer posting, online food advertising…)
what are the key messages from Adolescent Nutrition 3 – Strategies and intervention for healthy adolescent
growth, nutrition and development - Lancet series
Key messages:
* Double burden – despite micronutrient deficiencies/food insecurities, overweight and
obesity rapidly increasing
* A lack of targets/standardised data to inform action, and nutritional action (but this life
stage sets foundation for a healthy start to life for the next generation)
* Multifaceted/multisectoral action great promise, to date only focused on single
micronutrient
* Greater government fiscal and policy action to restrict availability of highly processed
foods and enhance healthy/diverse adolescent diets – urgency needed
* Greater retention in education means schools can provide healthy food environments,
skills/knowledge and motivation to adopt and sustain healthy diets
* Advocacy in partnership with young people
lancet series 3 recommendations
✓ Build commitment to adolescent nutrition through evidence-based and
accountable systems *
✓ Enhance policy and programmatic actions that favour healthy adolescent
nutrition **
✓ Place adolescent nutrition advocacy within a broader ecological
context…“partner with young people in advocacy”
why is research and development in adolescence a missed opportunity?
- Inadequate focus, funding and intervention on adolescent health
- Interventions and investments are needed in adolescence
- Greater visibility and understanding of adolescent food choices and their consequences
- Benefits later adult life and optimal growth of next generation
- Opportunity to interrupt intergenerational cycles of malnutrition
energy requirements in adolescence and impact of deficits
- Adolescent requirements can be as high as that for adulthood
- Provided by carbohydrate, protein and fat
- Deficits may result in poor growth and failure to reach height potential (stunting)
carbohydrate requirements in adolescence and impact of deficits
- Primary energy source for optimal brain function and to preserve protein for other functions
- AMDR: 45-65% total energy
- Preferred source: wholegrain products which contain more fibre and micronutrient
fat requirements in adolescence and impact of deficits
- AMDR: 20-35% total energy, with <10% from saturated fat
- Replacement of saturated fat with unsaturated fats is beneficial, however some saturated fats in some food
sources may be protective for chronic disease (e.g., in dairy products). - Consume omega-3 fatty acids regularly (oily fish, seafood, soy, seeds, nuts, dark green veg, canola, eggs)
importance of fibre during adolescence
- Associated with healthier bowel, improved blood cholesterol, blood glucose, blood pressure, lower weight
- Concern with the rise of processed foods
key micronutrients for adolescence and why
Zinc
* High to meet requirement of growth and sexual development
Folate
* B-group vitamins required to assist in releasing energy for use for rapid growth
* Particularly important for pregnant adolescents
Calcium
* More than 50% of bone mass is developed during adolescence!
* Adequate calcium essential to achieving peak bone mass and reduce risk of osteoporosis
Vitamin D
* Sun exposure to be balanced with risk of skin cancer
* Where there is minimal outdoor time, food sources of Vitamin D (fortified milk, margarine and
eggs) or supplement should be considered if serum levels are low
Iron
* Increases to meet demands of rapid growth (increase blood volume & muscle mass) and for females the beginning of menstruation
importance of iron in adolescence and deficiency impacts
- Increases to meet demands of rapid growth (increase blood volume & muscle mass) and for females the beginning of menstruation
- Inadequate iron leads to
→ compromised growth
→ decreased cognitive function
→ physical performance and fatigue
→ depressed immune function - Little reduction over three decades in iron deficiency anemia
- Third most important cause of lost disability-adjusted life-years in adolescents
- Teenage pregnancy (link back to week 3 lecture and see adolescence nutrition and health)
are australian adolescence meeting recommended dietary intake
no under-eating fruit, veg, grain foods, meat and alternatives and, dairy and alternatives. overeating discretionary foods
concern between weekdays and weekends
- Increased choice of discretionary food
- Added sugar intake significantly higher on weekends
- Fibre intake lower
adolescent nutrition and health concerns
- Added free sugars
- Energy drinks
- Alcohol
- Overweight and obesity
- Academic performance
- Vegetarianism
- Eating disorders
- Adolescent pregnancy
- Physical activity
