Adolescence Flashcards
Age guidelines for adolescence
Early adolescence: 12-14 years
Mid-adolescence: 15-17 years
Late adolescence: 18-21 years
same as the periods of psychosocial development
Normal physical growth and development that occurs during adolescence
Puberty => body matures that of a child to a young adult
- early adolescence
- sexual maturation
- increases in height and weight
- accumulation of skeletal muscle
- Changes in body composition
Sequence of maturation events is consistent but a lot of variation
- this affects nutrition requirements of adolescents
- this should be used to assess growth and development and nutritional needs, not age
Describe Sexual Maturation Rating or “Tanner Stages”
Scale of secondary sexual characteristics used to assess degree of pubertal maturation
- SMR 1 = pre-pubertal growth and development
- SMR 2 -5 = occurrences of puberty
- SMR 5 = sexual maturation has concluded
Based on:
- breast development and appearance of pubic hair in females
- Testicular and penile development in males
Describe the maturation and growth of females
- Menarche (onset of first menstrual period) occurs 2-4 years after initial development of breast buds
- age of menarche ranges from 9 to 17 years
- peak linear growth occurs ~6 to 12 months prior to menarche
- Highly competitive athletes with severely restricted diets may have delay or slow growth
Describe the maturation and growth of males
- Males show great deal of variation in chronological age at which sexual maturation takes place
- Peak velocity of linear growth occurs during SMR 4 and ends with appearance of facial hair at age 14.5 years
- Linear growth continues throughout adolescence ceasing at age 21
Changes in weight, body composition, and skeletal muscle in females
As much as 50% of ideal adult body wt is gained during adolescence
- Slows down at time of menarche, but continues into late adolescence
Peak accumulation of muscle occurs around or just after onset of menses
- Gain avg of 2.5 lbs (1.14 kg) of body fat mass each year during puberty
- Body fat levels peak age 15-16 yrs
- ~17% body fat is required for menarche to occur
Changes in weight, body composition, and skeletal muscle in males
Peak wt gain at the same time as peak linear growth & peak muscle mass accumulation
Peak wt gain, ~20 lb per year
Body fat decreases to ~12%
~Half of bone mass is accrued in adolescence
- By age 18, more than 90% of skeletal mass has been formed
Energy and Nutrient Requirements of Adolescents
Increases in lean body mass, skeletal mass and body fat
Energy & nutrient needs during adolescence exceed those of any other point in life (pregnancy may be only exception)
Needs correspond to physical maturation stage
Energy needs are influenced by:
Activity level
BMR
Pubertal growth and development
Sex
DRI for adolescents for PRO
0.95 g/kg body wt (9-13 yrs)
0.85 g/kg body wt (14-18 yrs)
or 10-30% of energy
What results are linked to low protein intakes?
Reductions in linear growth
delays in sexual maturation
reduced lean body mass
DRI for adolescents for CHO and fiber
Carbohydrates:
- 130 g/day or 45-65% of calories
Dietary Fiber:
- Avg intake/d: males 16.4 g, females 12.6 g
- DRI recommends:
Female (9-18 yo) 26 g/day
Male (9-13 yo) 31 g/day
Male (14-18 yo) 38 g/day
DRI for adolescents for Fat
Required as dietary fat and essential fatty acids for growth and development
25-35% of calories from total fat
<10% calories from saturated fat
Calcium requirements during adolescence (and why it is needed)
Critical to ensure peak bone mass
DRI for ages 9-18 years is 1300 mg/d
Approx. Average intake:
937 mg for females
1311 mg for males (ie. much lower)
Weight bearing activities increase bone mineral density
~4 times more calcium retained during early adolescence compared to early adulthood
those who do not consume dairy should consume calcium fortified foods
When is calcium absorption rate the highest in females and males?
Menarche
Early adolescence
