11) Fat, Carbohydrate, Water, Mineral, Electrolyte, and Vitamin Requirements in Infancy, Childhood, and Adolescence Flashcards
What must the energy balance during childhood and adolescence balance?
- Energy expenditure
- A level of physical activity that is consistent with good health
- Must include energy associated with tissue deposition
The energy requirements for growth are (low/high) in comparison to maintenance.
low
The energy requirements for growth are low in comparison to maintenance, apart from which period? Why?
The first few months of life, in which growth is substantial
What are the two components for the energy needs for growth? (2)
1) Energy used to synthesize growing tissues
2) Energy deposited in those tissues
The energy cost of growth in children is largely derived from which children?
Pre-term infants and children recovering from malnutrition
In practicality, when is the energy cost of growth particularly an issue in infancy?
Only during the first half of infancy, in which energy deposition contributes significantly to energy requirements
What equation is used to predict the TEE for individuals aged 0 to 2 years old? How does it vary between boys and girls?
- EER = TEE + Energy Deposition
- It does not vary between sexes
The number of calories required for energy deposition (decreases/increases) as infancy progresses.
decreases
How is the energy content of tissue deposition computed?
From rates of protein and fat deposition
Why isn’t the PAL included in the calculation to determine the EER of individuals aged 0 to 2 years old?
Because there is very little physical activity
What allows for the determination of whether a child is acquiring a sufficient quantity of calories?
Growth velocity
How does the determination of energy status compare between growth velocity and growth charts?
- Growth velocity is a sensitive indicator of energy status
- Indicates whether growth faltering is occurring earlier than growth charts
What does weight velocity indicate? What does length velocity indicate?
- Weight velocity indicates acute episodes of dietary intake
- Length velocity indicates chronic factors
When are nutrient requirements on a per-weight basis highest in the life cycle? Why?
- During the first six months of life
- Characterized by the most rapid growth rates
Pre-mature infants possess an energy requirement around __% higher than term infants.
20
Why do pre-mature infants possess a greater energy requirement than term infants?
1) They have a higher basal metabolic rate
2) They have a lower coefficient of absorption of fats and carbohydrates
On a per-kilogram basis, energy expenditure is two times (smaller/greater) in infants than in adults.
greater
What are the primary organs contributing to the infant’s basal metabolism?
- Brain
- Liver
- Heart
- Kidney
What does the transition from an intrauterine to an extrauterine environment alter in the infant?
Causes an increase in oxygen consumption in the infant
Why do infants have a proportionally high BMR for their size?
Increased oxygen consumption of vital organs in proportion to their weight
How does the energy cost of growth vary throughout the first month of life?
- 35% during the first month
- 3% at 12 months
- 1% at 5 years old
What are the periods associated a greater energy cost of growth?
- Infancy (0 to 2 months)
- Adolescent growth spurt
What does the exposure of a newborn to mild cold result in? What does the exposure of a newborn to even lower temperature result in?
- Non-shivering thermogenesis (cold)
- Shivering thermogenesis (colder)
What is the most important contribution to non-shivering thermogenesis?
An increase in fatty acid oxidation in BAT
How does the quantity of BAT vary between infants and adults?
Infants possess a greater quantity of BAT than adults
How does the function of WAT compare to BAT?
- WAT is primarily used as a site for energy storage
- BAT is used to burn fat to produce heat and regulate body temperature
What are structural characteristics of BAT that contribute to its function? (4)
- Highly vascularized
- Innervated by the CNS
- Multilocular (multiple lipid droplets)
- Greater proportion of mitochondria
What structure is responsible for the production of energy dissipated as heat in BAT?
- UCP1 is responsible for the uncoupling of oxidative respiration from ATP production
- Increases proton leakage across the inner membrane of the mitochondria of BAT
Where is UCP1 contained? What is it activated by?
- Contained in the mitochondria
- Activated by free fatty acids and the sympathetic nervous system
What is UCP1 inhibited by in a thermoneutral state?
The presence of ATP in the cytoplasm
How may white adipocytes influence BAT cells?
May play an inflammatory role by producing cytokines and chemokines, which can cause a cytotoxic effect on BAT cells
As the child ages, physical activity becomes a (smaller/larger) component of the TEE.
larger
What equation is used to predict the TEE for individuals aged 3 to 8 years old? How does it vary between boys and girls?
- EER = TEE + Energy deposition
- The EER is higher in boys than in girls
Why is the EER higher in boys than in girls (aged 3 to 8 years old)? (2)
1) Weight differences
2) Fat-free mass differences
What are the three factors that contribute to the BMR? (3)
1) Mass of metabolically active tissue
2) Proportion of each tissue
3) Contribution of each tissue to energy metabolism
What is the energy cost of growth based on in children aged 3 to 8 years old?
Weight gain, protein and fat deposition
What is the energy deposition in children aged 3 to 8 years old?
20 kilocalories per day
What may the calculation of energy needs in the case of catch-up growth utilize? (2)
1) The 50th percentile of weight or height for the age
2) Energy requirement of the actual age multiplied by 1.2 to 1.5 or 1.5 to 2.0
What is the energy deposition in adolescents aged 9 to 18 years old?
25 kilocalories per day
What is the energy deposition in adolescents during the peak growth spurt?
Increase (30 kilocalories per day)
What is the energy deposition in adolescents during the peak growth spurt?
Increase (30 kilocalories per day)
What may increase energy requirements during adolescence? (2)
1) Development of reproductive organs and secondary changes during puberty
2) Occupational and recreational physical activity
What forms the bulk of active metabolic tissue?
Fat-free mass
Why is there a higher energy and nutrient requirement in adolescent boys?
Marked gender differences in terms of the intensity and duration of the growth spurt leads to disparities in terms of the fat-free mass
Growth is relatively (slow/fast) during adolescence.
- slow
- Apart from the adolescent growth spurt
There are __ grams of carbohydrates per liter of milk.
74
What volume of milk is consumed in infants from 0 to 6 months? What percentage of the milk corresponds to carbohydrates?
- 0.78 liters per day
- 37% of the total intake is derived from carbohydrates
What is the median carbohydrate intake from weaning foods?
50 grams per day
What volume of milk is consumed in infants from 6 to 12 months?
0.6 liters per day (44 grams of carbohydrates per day)
What is the carbohydrate recommendation in infants aged 0 to 6 months?
60 grams per day (AI)
What is the carbohydrate recommendation in infants aged 6 to 12 months?
95 grams per day (AI)
What is the effect of non-milk extrinsic sugars in children?
Produce a dilution effect in terms of micronutrients
What is the carbohydrate requirement for infants above the age of 1?
130 grams per day (RDA)
Why is the carbohydrate requirement for children above the age of 1 the same as for adults?
Because the brain glucose consumption after age 1 is consistent, or increases modestly
Fiber intake recommendations are set as a function of ______ intake.
energy
How does the recommendation for fiber vary across age groups?
A decreased energy requirement (lower in younger individuals) results in a lower fiber requirement
What is the consequence of an excess quantity of fiber?
May decrease the quantity of minerals absorbed (e.g. calcium and iron)
What is the recommendation for fiber in infants below the age of 1?
- There is no functional criterion for fiber status
- There is NO dietary fiber in breastmilk
What is the AI for protein based on in infants from 0 to 6 months?
The average milk volume and the average protein content
What is the average milk volume from 0 to 6 months?
0.78 liters per day
What is the average milk volume from 6 to 12 months?
0.6 liters per day
How does the protein intake vary between breastfed and formula-fed infants?
Protein intakes are higher in formula-fed infants
______-fed infants gain more weight and lean-body mass. Is it related to protein intake?
Formula
- A greater protein intake from formula is NOT associated with these effects
What does the Early Protein Hypothesis state?
A high protein consumption early in life increases plasma concentrations of insulin-releasing amino acids
What is the consequence of a high concentration of insulin-releasing amino acids early in life?
- Increase in IGF-1
- Enhances weight gain and body weight deposition
- Increases the risk of adiposity and obesity later in life
A study analyzed the effects of reducing the protein contents of formula to a level that is similar in breast milk. What were the results?
- Decreased plasma concentrations of essential amino acids, insulin and IGF-1
- Increased fat oxidation
- Reduced the prevalence of obesity
What is utilized to estimate the protein EAR for children aged 7 months to 18 years of age?
Factorial method
What are the three components of the factorial method used to estimate the protein EAR for children aged 7 months to 18 years of age?
1) Estimates of maintenance requirement
2) Measurement of rates of protein deposition
3) Estimates of the efficiency of protein utilization for growth
How does the EAR for older infants aged 7 to 12 months, determined via the factorial method, compare to the AI?
The EAR is slightly lower than the AI based on the mean protein content of human milk and complementary foods
Which nutrient requirement is used to assess protein content in infants aged 0 to 6 months, and in older infants aged 7 to 12 months?
- Young infants (0 to 6 months): AI
- Older infants (6 to 12 months): EAR determined by the factorial method
How does the protein requirement (on a body-weight basis) compare between children aged 1 to 18 years old and adults?
The protein requirement is similar
How is the fat requirement in infancy determined?
- Young infants (0 to 6 months): AI based on fat content of breast milk
- Older infants (6 to 12 months): AI based on fat content of breast milk and complementary foods
How is the fat requirement determined for children and adolescents?
There is NO AI, EAR or RDA for total fat intake in these age groups
How does the AMDR for fat vary as childhood progresses?
The AMDR for fat decreases as childhood progresses
What are the risks of consuming a low-fat diet during childhood?
Inadequate intakes of essential fatty acids and fat-soluble vitamins
How are the omega-3 and omega-6 requirements in infancy determined?
- Young infants (0 to 6 months): AI based on fatty acid content of breast milk
- Older infants (6 to 12 months): AI based on fatty acid content of breast milk and complementary foods
How are the omega-3 and omega-6 requirements determined for children and adolescents?
- The AI is based on the median intake in US and Canadian populations, demonstrating a lack of deficiency symptoms
- The IOM recommends an omega-6 to omega-3 ratio between 5:1 and 10:1
Why are the AIs for omega-6 and omega-3 fatty acids higher in boys than in girls?
- Energy expenditure increases fat oxidation
- Omega-6 and omega-3 fatty acids are readily used for energy
How is the requirement for water in infancy determined?
- Young infants (0 to 6 months): AI based on water content of breast milk
- Older infants (6 to 12 months): AI based on water content of breast milk and complementary foods
How are water requirements determined for children and adolescents?
- There is no single water intake level that can be recommended
- Normal hydration status may be achieved over a wide range of total water intakes
- The AI is based on the median total water intake of healthy populations
How are sodium and chloride requirements in infancy determined?
- Young infants (0 to 6 months): AI based on sodium and chloride content of breast milk
- Older infants (6 to 12 months): AI based on sodium and chloride content of breast milk and complementary foods
How do sodium and chloride requirements differ between children, adolescents and adults?
- There is no reason to expect that the sodium requirement of children and adolescents are different than adults
- The maturation of the kidneys is similar
How are sodium and chloride requirements determined for children and adolescents?
The AI is extrapolated from the adult AI, using the average of median energy intake levels of age groups
How is the requirement for potassium in infancy determined?
- Young infants (0 to 6 months): AI based on potassium content of breast milk
- Older infants (6 to 12 months): AI based on potassium content of breast milk and complementary foods
What are possible consequences of potassium deficiency?
- Increase in blood pressure
- Bone demineralization
- Kidney stones
How does a deficiency in potassium affect sodium?
- Increases sodium re-entry to maintain cellular volume
- Increases water retention
- Results in an increase in blood pressure (stiffness and hypertension)
How is potassium citrate related to kidney disease?
- Potassium citrate is a precursor for bicarbonate
- Acts to counteract the calcium-carbonate release, which retards kidney disease or calcium-containing kidney stones
How is the requirement for potassium determined for children and adolescents?
Extrapolated from recommended intakes of potassium from adults to children on the basis of the average of median energy intake levels
Why is the requirement for potassium in children and adolescents based on energy intake and not weight?
Because basing the requirement on weight may lead to relatively low and potentially inadequate intake of potassium
How are maintenance requirements for micronutrients extrapolated from adults to infants and children?
EARchild = EARadult (F) where F = (Weightchild/Weightadult)^0.75
Why can’t the ratio of a child over an adult be used as a method to extrapolate data?
Because it would result in a higher percentage than represented by the actual weight
How does the BMR vary based on body weight (allometric)?
As the body weight of an organism increases, the BMR decreases
How are growth requirements for micronutrients extrapolated from adults to infants and children?
EARchild = EARadult (F) where F = (Weightchild/Weightadult)^0.75 (1 + Growth Factor)
How are growth factors determined?
By a study that produced an approximate proportional increase in protein requirements for growth, which is used as an estimate for the growth factor
What is the growth factor of females beyond 13 years of age?
Assumed to represent a negligible increased requirement
Which type of infants are recommended to be given a daily 400 IU vitamin D supplement?
- Breastfed infants
- Infants consuming formula that are not fortified with vitamin D
- Infants that consume less than 1 liter of fortified milk
Which type of child is recommended to be given a daily 400 IU vitamin D supplement?
Children above a year of age, consuming an insufficient quantity of cow’s milk (below 2 cups per day)
Why is there a rapid increase in the AI of vitamin K from infancy to childhood?
Older children consume a greater quantity of fiber-rich foods, allowing for a greater intake of vitamin K
Why are infants at an increased risk of vitamin K deficiency at birth?
- Vitamin K is not efficiently transported across the placenta
- Infants lack intestinal flora
What increases the risk of hemorrhagic disease of a newborn?
The low concentration of clotting factors
Differentiate hemorrhagic disease of the newborn and late hemorrhagic disease of the newborn.
- Hemorrhagic disease of the newborn has an early onset (birth to 3 weeks)
- Late hemorrhagic disease of the newborn has a late onset (3 to 8 weeks)
What is late hemorrhagic disease of the newborn associated with?
Breastfeeding, as there is a low quantity of vitamin K in breastmilk, compared to cow’s milk and formula
How may hemorrhagic disease of the newborn be effectively prevented?
By the administration of vitamin K
How is the requirement for vitamin K determined infants (0 to 6 months)?
Based on the vitamin K intake of infants principally fed breast milk and provided vitamin K prophylaxis
From 6 to 12 months, the vitamin K intake is expected to be (above/below) the AI based on human milk consumption. Why?
above
- Due to the increase in consumption of complementary foods
How is the AI of vitamin K for infants aged 6 to 12 months determined?
It is extrapolated up from the AI of infants aged 0 to 6 months
Why is the AI of vitamin K for infants aged 6 to 12 months not extrapolated down from adults?
The AI produced would be too high, which would be impossible to reach without a supplement
How is the requirement for vitamin K determined for children and adolescents?
Based on the highest median intake for an age group for which there are no signs of deficiency
Clinically significant vitamin K deficiencies are extremely rare in children and adolescents. In which scenarios would they be observed?
- Individuals with malabsorption syndromes (e.g. Celiac’s disease)
- Individuals consuming drugs interfering with vitamin K metabolism
What is reduced vitamin K a cofactor for?
y-glutamylcarboxylase
What is the mechanism of action of y-glutamylcarboxylase?
Catalyzes post-translational modifications of certain glutamic acid residues in vitamin K-dependent proteins
What is y-glutamylcarboxylase required for? (2)
1) Activity of coagulation
2) Binding of osteocalcin to hydroxyapatite in bone (bone deposition)
Describe the vitamin K cycle.
- The reduced form of vitamin K is oxidized to an epoxide after it is utilized as a cofactor
- The epoxide is reduced by vitamin K epoxide reductase to regenerate the active reduced form of vitamin K
How does Warfarin interfere with the vitamin K cycle?
- Inhibits vitamin K epoxide reductase
- The reduced form of vitamin K is utilized and may not be regenerated, causing anti-coagulant effects
What is the calcium recommendation based on for children aged 1 to 8 years old?
Calcium accretion
What are the three major lines of evidence concerning calcium requirements for children and adolescents aged 9 to 18 years old?
1) Factorial approach
2) Calcium retention to meet peak bone mineral accretion
3) Clinical trials, where bone mineral content is measured in response to variable calcium intake
What functional criteria is used for the determination of iron status in infants aged 0 to 6 months?
- There is no functional criteria
- The AI is based on the intake from breast milk
What are the major components of iron requirements for infants aged 6 to 12 months? (4)
1) Obligatory basal losses
2) Increased hemoglobin mass
3) Increased tissue (non-storage) iron
4) Increased storage iron
How does the bioavailability of iron differ in infants aged 6 to 12 months? Why?
- Bioavailability is lower (10%, as opposed to 18%)
- Because the diet is low in meat
What is the most common nutritional disorder in the world?
Iron deficiency
What are the major components of iron requirements for children aged 1 to 8 years of age?
1) Basal losses
2) Median total iron deposition
What are the major components of iron requirements for adolescents aged 9 to 18 years of age?
1) Obligatory basal losses
2) increased hemoglobin mass
3) Increased tissue (non-storage) iron
4) Menstrual iron losses in adolescent girls
When are iron stores assumed to be filled, and are no longer a component of iron requirements?
By 9 years of age
What are the needs for absorbed iron associated with in adolescence?
- Growth
- Increase in body weight
- For example, 0.035 mg of iron is required for every gram of weight gained in boys
How is the additional weight gain during the peak growth spurt determined?
The difference between the maximum and average growth rate
By the age of __, girls are assumed to almost all have started to menstruate.
14
What is the iodine requirement for children aged 1 to 8 years old based on?
A study concerning children that were previously malnourished and subsequently rehabilitated
How does the AI for fluoride vary with age?
- There is no AI associated with infants aged 0 to 6 months
- The AI is 0.05 mg/kg/day in all age groups, and varies based on body weight
Why is the AI intake range of fluoride recommended for all ages? (2)
1) It confers a high level of protection against dental caries
2) It is associated with no known unwanted health effects
What is the cause of enamel fluorosis?
Fluoride ingested during the pre-eruptive development of teeth
At what point are children no longer susceptible to enamel fluorosis? Why?
- 8 years of age
- Because the enamel has completed pre-eruptive maturation
What is the UL for fluoride in children aged 0 to 8 years old based on?
The threshold beyond which moderate enamel fluorosis appears
What is associated with the development and severity of enamel fluorosis?
The level and duration of exposure
