10) Adolescence Flashcards
Define a growth spurt.
Peak height velocity (fastest rate at which we are gaining height)
What is the period of highest nutritional needs during adolescence?
During growth spurts
During the growth spurt, there is an accretion of __% of the adult height and __% of weight.
20
50
How does the timing of the growth spurt vary between individuals?
There is a high variability in terms of the timing of the growth spurt
What age determines sexual maturity?
Age alone does NOT determine the stage of maturity of the adolescent
What is the best index for determining nutrient needs in an adolescent?
Caloric requirement is based on kilocalories per centimeter of height
What are the periods post-utero in which growth velocity increases?
Puberty is the ONLY period post-utero in which growth velocity increases
How does the age of puberty vary between girls and boys?
Puberty starts earlier in girls
What are the two factors that explain the fact that adult men are taller than adult women?
1) There is a longer of pre-pubertal growth in boys because the growth spurt occurs later in boys
2) Boys have a greater peak height velocity
When does menarche occur?
12 or 13 years old
The pubertal growth spurt is characterized by twice the incorporation of which nutrients into bone?
- Calcium
- Magnesium
- Zinc
- Iron
Chronological age is a (better/worse) indicator of nutritional requirement than maturational age.
worse
Nutrient needs during adolescence are determined individually according to which three factors?
1) Intensity and extent of the pubertal growth spurt
2) Gender differences in growth and body composition changes
3) Differences among individuals in terms of the timing of the pubertal growth spurt
What are Tanner’s SMRs? What are they based on?
- Sexual Maturation Ratings
- Used clinically to describe the sexual stage of development
- Based on differences in primary and secondary sexual characteristics
How is the timing of growth related to SMRs?
- The sequence at which development occurs is predictable
- The timing of growth is predictable
How are growth charts used during puberty?
- Growth charts are less accurate during puberty
- The rates and patterns of growth vary, often producing crossing of growth channels
What are the SMR stages?
Vary from SMR 1 (pre-pubertal) to SMR 5 (adult)
What are the characteristics of SMR 1?
Rapid growth, but no discernable sexual changes
How does the timing of bone mass accretion and skeletal growth vary between boys and girls?
They DIFFER between females and males due to variability in the stage at which the growth spurt occurs
When is the peak weight accumulation in females in relation to peak height velocity?
6 to 9 months PRIOR to peak height velocity
When is the peak weight accumulation in males in relation to peak height velocity?
At the same time as peak height velocity
When does lean body mass occur in females and males? What SMR stage does that correspond to?
- Females: peaks at SMR 3-4
- Males: SMR 5 (after stature gain is complete)
When does sexual maturation takes place in females in comparison to males? How does the end of sexual maturation relate to growth in females?
- Takes place earlier in females than in males
- Growth normally stops when girls finish their sexual maturation
When does menarche occur in relation to breast development?
- One year after breast development begins
- Usually occurring at the deceleration phase of growth
Menses at a later age is associated with a (shorter/longer) period of growth.
longer
How does the end of sexual maturation relate to growth in males?
Growth can continue after sexual maturation has ended
How does the total period of growth and pre-pubertal growth vary between boys and girls?
Boys have a longer total period of growth and longer pre-pubertal growth
Which hormones are responsible for development during adolescence?
- Growth hormone
- Testosterone
- Adrenal androgens
What is the mechanism by which the final stage of skeletal growth occurs?
When the epiphyses fuse with the main portion of the bone
What is the importance of calcium during adolescence?
- Adolescence is a critical period for achieving bone mass
- Prevents osteoporosis and osteopenia
How does adolescence affect lean body mass in males and females?
- Increases LBM in males
- Decreases LBM in females
Why do males require higher amounts of nutrients and calories during growth spurts than females?
Because they possess a higher proportion of LBM, which has a higher metabolic activity than fat mass
What characteristics must be present in females to allow for the onset of menses?
- Must possess a critical body mass of 47.8 kg (105 pounds)
- Must possess a body fat composition of at least 17%
How does testosterone affect development in boys during adolescence?
- Significant increase in bone and muscle growth
- Loss of fat
How does the quantity of LBM and number of muscle cells differ between adult males and females?
Adult males possess 150% the LBM of females and twice the number of muscle cells
When do skeletal minerals accumulate in females? How much?
1/3 of total skeletal minerals accumulated in the 3 to 4 years after the onset of puberty
What is delayed puberty and secondary amenorrhea associated with in adult females?
Decreased bone mineral density
What occurs in females as height velocity decreases?
Fat accumulation resumes
What corresponds to the time of peak height velocity?
Maximum fat loss and muscle mass increase in upper arms
Which hormones promote the deposition of bone minerals?
Both androgens and estrogens
What characteristics govern external and internal factors that influence eating behaviours in adolescents?
- Socio-economic and political system
- Food availability, production, and distribution system
What are external factors that influence eating behaviour?
- Family unit and family characteristics
- Parenting practices
- Peers
- Social and cultural norms
- Mass media
- Fast foods
- Food fads
- Nutrition knowledge
- Personal experiences
What are internal factors that influence eating behaviour?
- Physiological needs and characteristics
- Body image
- Self-concept
- Personal values and beliefs
- Food preferences and meanings
- Psychosocial development
- Health
What types of parenting practices adversely affect eating behaviour? How?
- Extreme rigidity and extreme permissiveness
- Rebellion, purging, binging, food faddism, and fasting
What are the risks of food fads in adolescents?
- Food fads are popular among adolescents (used to exert their independence)
- If they do not possess the proper knowledge, they may suffer from nutritional deficiencies
How is smoking related to eating behaviours in adolescents?
- Nicotine decreases food intake and increases weight loss
- Smoking eases hunger signals
- Quitting smoking is associated with weight gain
What are the risks of dieting during adolescence?
- Increases the risk of nutrient deficiencies
- Increases the risk of life-long weight cycling
How does dieting lead to weight cycling?
1) A drop in body weight causes a drop in BMR
2) Changing back to the regular diet causes a greater weight gain
3) The weight gain is associated with a greater gain of adipose tissue, further decreases the BMR, making it harder to lose weight
What may allow teenagers to exert more independent food choices?
Developing conceptual problem-solving skills
Obesity is caused by a complex mix of environmental (__%) and genetic factors (__%).
20
80
How many genes are associated with obesity? Give examples of their roles.
- 130 genes
- Genes may regulate the speed at which the gut informs the brain that the individual is full, or how effectively the body converts extra calories into fat
What are possible aerobic adaptations of exercise? How do they vary among individuals? What does that indicate?
- Stronger heart and muscles, increased maximal oxygen uptake by lungs, and increased heart circulation
- Certain individuals do not respond to exercise in the same way (indicating a genetic component)
How does obesity affect teenagers as opposed to younger children?
- Obesity affects the psyche of teenagers much more than younger children
- Obesity in children does not impair socialization nor cause long-term psychological harm
What may a sense of poor self-worth lead to?
Greater passivity and dependency, as well as an increased risk of teasing and discrimination
What may drive a teenager to use food as a comfort source? What does it result in?
- A teenager withdrawing from social contact and physical activity
- Results in greater obesity, bullying and discrimination
What percentage of obese teenagers remain obese as adults?
80%
Why must a teenager be conscious of the pubertal growth spurt?
To prevent them from restricting their calories in hopes to avoid weight gain
What are the consequences of a restriction in calories during the pubertal growth spurt? (2)
Linear growth restriction and nutritional dwarfism (growth failure, short stature, and delayed puberty)
Which socio-economic populations are susceptible to eating disorders?
White, middle/upper class females with depression and/or family dysfunction
What are the four diagnostic criteria for anorexia nervosa? (4)
1) Absence of known medical or psychiatric illness
2) Body weight is 15 to 20% below expected body weight
3) Intense fear of gaining weight
4) Absence of at least three menstrual cycles
What personality traits do individuals with anorexia tend to possess?
Anxious, fearful, or dependent personality
What type of family do individuals with anorexia tend to arise from?
- Achievement-oriented families
- Psychopathology or dysfunction within the family is a common characteristic
What are the two types of anorexia nervosa?
1) Restrictive anorexia nervosa
2) Binging-purging anorexia nervosa
What are characteristics of restrictive anorexia nervosa?
Restriction of caloric intake, in which there is a lack of purging behavior
What are characteristics of binging-purging anorexia nervosa?
Food binging, followed by purging through vomiting, diuretics, laxatives, or intense exercise
What is the usual cause of mortality in anorexia nervosa?
Multiple organ failure
How does anorexia nervosa cause cardiovascular abnormalities?
- Electrolyte imbalance may lead to arrhythmia
- Inefficient heart pumping due to weakened heart muscles
What are GI issues that may be observed in anorexia nervosa?
- Diarrhea, cramping, fever
- Common symptoms, similar to Crohn’s disease and ulcerative colitis
Which eating disorder is Wernicke’s encephalopathy related to?
Anorexia nervosa (may result in death)
What is Wernicke’s encephalopathy?
Irreversible brain damage due to a deficiency in thiamine
What are other physiological effects of anorexia nervosa?
- Decrease in blood pressure
- Kidney dysfunction
- Muscle wasting
- Decreased BMR
- Defective thermoregulation
How may the restriction of food intake lead to the cessation of menstruation?
- The body progressively reaches a starvation stage
- Decreased estrogen levels
What are symptoms characteristic of changes in body function in response to starvation?
- Dry skin
- Hirsutism
- Thin, brittle, dry hair
- Hair loss
- Dehydration
- Edema
What is the diagnostic criterion for osteopenia?
- Decrease in bone density greater than 1 standard deviation, but less than 2.5 standard deviations, below the adult mean
- Increases the risk for osteoporosis
What is the diagnostic criterion for osteoporosis?
Decrease in bone density greater than 2.5 standard deviations below the adult mean
What does the recovery from bone loss in response to anorexia nervosa require?
A gradual infusion of calories, either by nasogastric feeding or total parenteral nutrition
Why is bone loss particularly critical in individuals with anorexia nervosa?
- Anorexia nervosa normally develops during adolescence, a period in which bones are still growing
- Malnutrition, or low-weight, may slow down or halt bone development
How does a decrease in nutrient and energy intake cause hormonal changes? What are their effects?
- Increase in cortisol
- Decrease in IGF-1 and leptin
- Slow down bone formation and increase bone loss
What is the ONLY effective treatment of osteoporosis due to anorexia nervosa?
- Weight gain
- Bone mass will increase after weight gain, particularly if periods have returned
What exercise regime should be recommended in individuals with anorexia nervosa, experiencing osteoporosis?
Exercise should be AVOIDED in these individuals (as opposed to the elderly)
Why should exercise be avoided in individuals with anorexia nervosa?
- Abnormal bone metabolism and osteoporosis are developing as a direct consequence to negative energy balance
- Exercise would be counter-productive to restoring energy balance
What condition may lead to low bone mineral density despite adequate weight-bearing exercise?
Hypoestrogenism due to pubertal delay or secondary amenorrhea
What are the characteristics of the psychological profile of individuals with anorexia nervosa?
- Distorted perception of their body proportions
- Psychological stress
- Disturbed family interactions
When does bulimia typically occur?
- Late adolescence or early adulthood
- After a series of unsuccessful weight-reducing diets
What personality traits do individuals with bulimia tend to possess?
- Outwardly successful
- Busy
- Frustrated
- Delay in psychosocial development
How is bulimia primarily distinct from anorexia nervosa?
- Individuals with bulimia normally possess a normal body weight
- They may undergo significant weight fluctuations in a short period of time
What are the four diagnostic criteria for bulimia? (4)
1) Individual is binging and purging over once per week for at least three months
2) Involves compensatory behaviours to prevent weight gain
3) Possess a distorted or ill-informed attitude regarding food and nutrition
4) Often self-evaluate according to body shape and weight, possessing a fear of gaining too much weight
Define binging.
Eating an excessive amount of food in a discrete period of time, characterized by a lack of control while eating
Define purging.
Regular self-induced vomiting or use of laxatives and diuretics to prevent weight gain
What is the non-purging type of bulimia called? What does it involve?
- Bulimarexia
- Involves the use of exercise or fasting, followed by binging
What are the characteristics of the psychological profile of individuals with bulimia?
- Anticipation, anxiety, and urgency to begin binging
- Rapid and uncontrollable intake of food
- Relief and relaxation followed by disappointment and shame
What are three consequences of the vomiting behaviour of bulimia? (3)
1) Irritation and infection of the esophagus and salivary glands
2) Erosion of teeth and dental caries
3) Electrolyte imbalances
How does excessive vomiting alter pH?
- Results in the loss of acidic hydrogen particles via stomach acid
- Excess bicarbonate, resulting in an alkaline pH
How does an excess of bicarbonate affect respiration?
May slow breathing rate
How does vomiting affect sodium and potassium?
- The body aims to restore water and pH balance by retaining sodium
- Results in hypokalemia (muscle weakness, twitching, and cramping)
What are other physiological effects of bulimia?
- Abnormal heart rhythms
- Kidney issues due to UTIs
- Dizziness
- Low blood pressure
- Decreased urine, dry mouth
What are emetics?
Drugs that induce vomiting
What are the effects of the overuse of emetics?
Heart failure due to fluid and electrolyte imbalances
Why do certain bulimics complain of heaviness and puffiness in their body?
- They think that it is due to fluid retention
- This is NOT true
- It is a perceptual problem dubbed broken eye syndrome
What is broken eye syndrome?
An individual perceives that they are bigger than they are
What are characteristics of non-specified eating disorders?
- Fear of obesity
- Hypercholesterolemia
- Decrease in food intake
What type of eating disorders do non-specific eating disorders include?
- Binge eaters who consume less during a binge, rarely purge, and show less restraint in dieting
- Atypical eating disorders (e.g. pica and rumination disorders)
What emotions do binge eaters share with other eating disorders?
- Lack of control
- Guilt
- Self-disgust
- Anxiety
What may reduced food intake and years of inadequate weight gain in non-specific eating disorders lead to?
Delayed sexual maturation and deteriorating linear growth
What are the four diagnostic criteria for binge-eating disorder? (4)
1) Loss of control over the amount of eating
2) Marked distress over the binge episode
3) Occurs at least once per week for three months
4) Three or more of typical characteristics
What are the five characteristics that may be present in binge-eating disorder? (5)
1) Eating more rapidly than normal
2) Eating until feeling uncomfortably full
3) Eating large amounts of food when not feeling physically hungry
4) Eating alone because of embarrassment over how much one is eating
5) Feeling disgusted with one-self, depressed, or very guilty after over-eating
What must healthcare professionals treated individuals with eating disorders keep in mind?
- Must appeal to the need for social acceptance
- Must instruct that a severe energy restriction results in a stronger trigger for binging
What pharmacological substances may be prescribed for individuals with eating disorders?
Anti-depressants (e.g. fluoxetine, Prozac, naloxone)
What is diet counselling used for in eating disorder treatment?
To allow individuals to incorporate nutritious eating habits in terms of quantity and quality to replace the distorted beliefs
What is the importance of eating breakfast?
Eating breakfast restricts greater energy intake at later meals, decreases the risk of binging, and is associated with an overall lower fat intake
