14: Adolescence Flashcards
What are some contributors to the timing of a growth spurt?
Genetics, light exposure at night, other environmental factors. Age can be a large variation.
How is a growth spurt defined?
Peak height velocity where 20% of adult height and 50% of adult weight is achieved.
What are some sex differences between growth spurt features?
Boys tend to have the growth spurt later, it’s greater in intensity, and lasts later. Means taller, higher bone mass, and higher LBM.
What are some nutrient requirement features of growth spurts?
Highest nutritional needs. 2x greater incorporation of Ca, Zn, Fe into bones. Chronological age a poor nutrient indicator, hard to estimate needs as vary hugely.
What can lead to early onset of menarche?
High exposure to estrogen if chemicals, low vit D status, inadequate darkness at night (melatonin low levels).
What can contribute to late onset of menarche?
ED, very active lifestyle, dieting, poor bone mass, too low body fat (<16%)
When is male sexual maturity compared to the growth spurt?
Tend to be more sexually mature before the growth spurt begins, and can continue the growth spurt after secondary sexual characteristics are complete.
What is tanners sexual maturation rating (smr) used for?
Describes the stage of development. Growth charts are less accurate during liberty, so best guide for growth and development.
What hormones are involved in the growth spurt?
GH, T, and adrenal androgens.
When is peak LBM accumulation for girls?
Between SMR 3-4 (peak and right after growth spurt)
What is the peak LBM accumulation for boys?
SMR 5 and onward.
What happens to LBM in girls vs boys during puberty?
Boys LBM increases, and girls actually decreases relative to fat.
What are some internal factors that alter lifestyle and individual behaviours?
Physiological needs, body image, self concept, personal beliefs, food preferences, psychosocial development (gaining independence), health.
What are some external factors that alter lifestyle and individual food behaviour?
Family, parenting, peers, social values, media, fast food, food fads, nutritional knowledge, personal experiences.
What are some social-economic factors that effect lifestyle and individual food behaviour?
Political system, food security.
Why are personal eating habits during adolescence important?
Growing and developing. Also likely that will have a critical effect on life long health as the habits formed will often carry through to adulthood.
What is the prevalence and risk of obesity in adolescence?
10-20%. Risk of high blood pressure, impaired glucose tolerance, sleep apnea , joint problems, early stages of arteriosclerosis.
How does food physiological act as a source of comfort?
Releases serotonin, and acts as an anti anxiety when food is overeaten.
What are some concerns about weight loss during adolescence, regardless of obesity?
May not reach optimal genetic potential for growth (only 61% will under caloric deficit). Focus instead on education, modifying to a healthier diet, and intervening on a family level.
What are some factors that aggravate the risk of developing anorexia?
Substance abuse , frequent dieting
List 5 clinical features of anorexia?
1- no known medical or psychiatric illness
2- body weight 15-20% below expected weight
3- intense fear of weight gain
4- absence of 3 or more menstrual cycles
5- disturbed self image
How is fatty liver sometimes developed in anorexia?
ApoB is needed to synthesize VLDL to bring TGs out of liver, and when there is protein malnutrition will not be able to synthesize adequate ApoB.
What is the minimum amount of body fat needed to maintain menstruation usually?
20-22%
What are the two types of anorexia?
Restrictive type, and binging/purging type (vomiting, diuretics, laxatives)
