Infancy, childhood and adolescence

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Infancy, childhood and adolescence
2013-03-26 17:49:36
NUTR 337 16

Infancy, childhood and adolescence
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  1. What is a good indicator of whether energy needs are being met?
    Satisfactory growth
  2. When is the energy cost of growth an issue in infants?
    Only during the 1st half of infancy
  3. How is energy content of tissue deposition computed for infants?
    • Computed from rates of protein and fat deposition (longitudinal studies)
    • ~175 kcal/d for 0 – 3 months -> 20 kcal/d for 13 – 35 months
  4. Why is there a single equation for EER for 0-2 years?
    Lack of gender differences
  5. Why is PAL not included in EER equation for infants?
    Limited range of physical activity?
  6. Why is growth velocity important in infants?
    • Sensitive indicator of energy status
    • Will detect growth faltering earlier than growth charts
  7. What is weight velocity in infants affected by?
    Acute episodes of dietary intake
  8. What is length velocity in infants affected by?
    Affected by chronic factors
  9. How does energy expenditure/kg compare from infants to adults?
    Energy expenditure/kg is 2x greater in infants than adults
  10. What is the energy cost of growth?
    • Energy content of newly synthesized tissue
    • Estimated from cost of protein and fat deposition
  11. Where do infants basal metabolism come from?
    Primarily brain, liver, heart and kidney
  12. Why does O2 consumption increase in infants?
    • Increase during the transition to extrauterine life
    • After birth, O2 consumption of these vital organis increases in proportion to increase in organ weight
    • Brain contribution exceptionally high (70%) in newborn, and in 1st years of life (60-65%)
  13. How does energy cost of growth vary throughout infancy?
    • Decreases from 35% at 1 month to 3% at 12 months
    • Remains low until pubertal growth spurt where it increases to 40%
  14. What happens when a neonate is exposed to milk cold?
    • Increase in non-shivering thermogenesis --> increase in metabolic rate
    • Most important contribution by increase oxidation of A in brown adipose tissue
  15. How does PA vary as a child grows?
    Increasingly larger component of TEE as child grows
  16. What is the purpose of energy requirements for adolescents?
    Defined to maintain health, promote optimal growth and maturation, support a desirable level of PA
  17. What is growth defined as?
    Increase in stature and weight, changes in body composition and organ systems
  18. What is adolescence defined as?
    Developmental changes in reproductive organs, development of secondary gender characteristics, changes in cardiorespiratory and muscular systems (increase strength and endurance)
  19. What is the bulk of the active metabolic tissue?
    Fat-free mass
  20. Why are there higher energy and nutrient requirement in boys during adolescence?
    Marked gender differences in intensity and duration of growth spurt in FFM
  21. What is the carbohydrate intake required during the first 6 months of life?
    ~60g CHO=37% of total food energy (amount in milk is assumed to be optimal)
  22. How much milk is consumed in the first 6 months of life?
  23. How much CHO is needed during 7-12 months?
    median CHO intake from weaning foods =50g/day
  24. How much milk is secreted at 7-12 months?
  25. Why is solid food needed at 7-12 months?
    • CHO from human milk=44g
    • CHO from foods = 50g
    • Total needed=94g
  26. What is the impact of added sugar on micronutrient intakes in infants?
    • Nutrient dilution effect by nonmilk extrinsic sugars
    • High [sugar] intake (>24% of energy)--> most micronutrient intakes between 6-20% below average
  27. Describe the rate of brain glucose consumption after age 1.
    • Constant of increases modestly
    • In the range reported for adults
    • EAR and RDA for CHO based n information used for adults
    • Same for both genders
  28. What is the AI for fiber for each age group?
    14g/1000kcal x median  energy intake
  29. Why are fiber recommendations a function of energy intake?
    • Individuals consuming less than median energy intake need less fiber
    • 1 year olds not meeting this energy consumption level will not require as much fiber and their intake should be scaled back accordingly
  30. Why do infants not need fiber?
    • No functional criteria for fiber status reflecting response to dietary intake
    • Human milk is the optimal source of nourishment and it contains no fiber
  31. Why are weight and lean body mass gains higher in formula-fed infants?
    Formula is higher in protein than milk
  32. Even though it is higher in protein, why is formula not as good?
    Despite lower protein intakes, breast-fed intants have better imune function and behavioural development
  33. How does protein intake change from 0-6 months to 7-12 months?
    • Stays about the same 1.52g/kg/day
    • May be a bit of an overestimate since growth slows down towards the end
  34. What method is used to estimate protein requirements?
    • Factorial method
    • Relationship between protein intake and nitrogen balance were utilized to estimate protein requirements by the factorial method
  35. What does the factorial method include?
    • Estimates of maintenance requirement
    • Measurement of rates of protein deposition
    • Estimates of the efficiency of protein utilization for growth
  36. What is the factor used in the factorial method?
    1.72 the efficiency of protein utilization for growth
  37. How much fat do infants need?
    • 0-6 months: 31g/day
    • 7-12 months: 30g/day
  38. Does human milk contain the correct amount of fat?
  39. For older infants, what is the fat AI based on?
    Based on average intake of fat from human milk and complementary foods
  40. How much fat do older infants get form complementary foods?
  41. What is the n-6 PUFA requirement for 0-6 months based on?
    • Amount of n-6 PUFAs in human milk
    • 4.4g/day
  42. How much PUFAs do 7-12 month olds get from complementary foods?
  43. What is the average energy intake from human milk and complementary foods for 7-12 month olds?
    • Milk: 390kcal/day
    • Foods:281kcal/ay
  44. What percentage of energy consumed is PUFAs in 7-12 month olds?
  45. Why is n-3 more important than n-6 for infants?
    Provide DHA which is important for the developing of the brain and retina
  46. What is the AI for n-3 for 0-6 month olds?
    • 0.5g/day
    • 1% of energy intake
  47. How much water is needed for 0-6 month olds and where does this number come from?
    • 0.68L/day
    • Because 0.78L of milk is consumed and milk s 87% water
    • Round to 0.7L/day
  48. How much water do 7-12 month olds need?
    Need 0.8L/day- comes from milk (0.52L) and complementary foods (0.32)
  49. What are water requirements in children based on?
    • Normal hydration status can be achieved with a wide range of total water intakes
    • AI for total water is based on median total water intake of children and adolescents
  50. What is the sodium and chloride AI in infancy based on?
    • 0-6 months: based on mean intake of milk-fed infants
    • 7-12 months: based on human milk and complementary foods
  51. Why are AI requirements of sodium and chloride  for 1-18 years similar to adults?
    Maturation of kidneys is similar im normal children by 12 months of age
  52. How is AI of sodium determined for children?
    • Extrapolated down from the adult AI of 1.5g/day
    • Using the average of median energy intake levels of the age groups for adults and for children
  53. What is the AI for potassium based on for 0-6 months?
    • Based on average amount of potassium in human milk
    • Mean intake: 0.39g/day (round to 0.4g/day)
  54. What is the AI for potassium for 7-12 months?
  55. What are some conditions resulting from potassium deficiency in children and adolescents?
    • Increased blood pressure, bone demineralization, kidney stones
    • Result from inadequate intake over an extended period of time, including childhood
  56. How are potassium intakes for children calculated?
    • Extrapolated from adult intakes
    • Adjusted based on energy intake
  57. Why is potassium AI not adjusted based on weight?
    • Adjusted based on energy intake
    • Concern that adjustment based on weight might lead to a relatively low and potentially inadequate intake of potassium
    • A greater intake of dietary K would be appropriate to mitigate adverse effects of Na
  58. How is the AI for Chloride set?
    • Set at a level equivalent on a molar basis to that of Na
    • Almost all dietary Cl comes with the Na added during processing or consumption of foods
  59. What is AI of vitamins and minerals for 0-6 months based on?
    • Mean intake data from infants fed human milk exclusively
    • Ad the [vitamin and mineral] of milk produced by well-nourished mothers
  60. How is the AI for vitamins and minerals for 7-12 months determined?
    Extrapolated from estimates of nutrient intake from human milk PLUS nutrients provided by usual intakes of complementary weaning foods
  61. How are maintenance needs for vitamins and minerals extrapolated from adults to infants and children?
    • Maintenance needs for vitamins and minerals expressed with respect to body weight (kgbody weight)^0.75
    • Set to power of 0.75 to adjust for mertabolic differences related to body weight
  62. How is the variability in requirements due to growth rate accounted for?
    A 10% CV for the requirement is assumed unless data are available to support another value
  63. How are AIs for vitamin K set?
    Set on the basis of the highest median intake for each age group
  64. Why is there a significant increase in AI for vitamin K from infancy to early childhood?
    Most likely due to the method used to set the AI for older infants and the increased portion of the diet containing vitamin K-rich fruits and vegetables as the diet becomes more diversified
  65. Why are newborn infants at risk for vitamin K deficiency?
    Vitamin K is poorly transported across the placenta
  66. What can happen as a result of low [plasma clotting factors] at birth?
    • Increased risk of bleeding during the first weeks of life
    • Hemorrhagic disease of the newborn
  67. What is late HDNB?
    • Between 3-8 weeks
    • Usually associated with breast-feeding
  68. How can HDNB be prevented?
    • Can be effectively prevented by administration of vitamin K
    • Infants born in North America routinely receive 0.5-1mg of phylloquinone i.m.
    • OR 2mg orally within 6 h of birth (less effective)
  69. How is AI for vitamin K determined?
    Reflects a calculated mean vitamin K intake of infants principally fed human milk and provided vitamin K prophylaxis
  70. How is older infant vitamin K AI obtained?
    By extrapolating up from young infants
  71. What is clinically significant vitamin K deficiency?
    • Extremely rare in the general population
    • Limited to individuals with malabsorption syndromes or those treated with drugs known to interfere with vitamin K metabolism
  72. What is the net Ca accretion and RDA for 1-3 years of age?
    • 100mg/day
    • Using an estimate of 20% net Ca retention
    • RDA is set for Ca at 700mg/day
  73. What is the RDA for Calcium for males and females aged 4-8 years?
    • Ca accretion=200mg/day
    • Require a Ca intake of 800 to 900 mg
    • RDA for calcium is 1000mg/day
  74. What are the 3 major lines of evidence for Ca needs for the 9-18 age group?
    • The factorial approach
    • Ca retention to meet peak bone mineral accretion
    • Clinical trials: bone mineral content measured in response to variable Ca intake
  75. What is the RDA for Ca for boys ages 9-18?
    1300mg/day: slightly above the 75th percentile of Ca intake
  76. What is the RDA for Ca for girls ages 9-18?
    • 1300mg/day
    • Slightly below the 90th percentile of Ca intake
  77. Why are calcium supplements needed in adolescents?
    • Current levels of Ca intake among adolescents not adequate to support development of optimal bone mass
    • Supplements may be necessary
  78. How is the AI for Fe determined for 0-6 month olds?
    • Reflects mean Fe intake of infants principally fed human milk
    • Assumed that the Fe provided by human milk si adequate to meet the Fe needs of infants exclusively fed human milk from 0-6 months
  79. What are the major components of Fe need for older infants?
    • Obligatory: fecal, urinary, and dermal losses (basal losses)
    • Increased hemoglobin mass (increased blood volume and increase in [hemoglobin])
    • Increase in tissue (non-storage) Fe
    • Increase in storage Fe
  80. What bioavailability is used to set Fe for 7-12 month olds and why?
    Use 10% bioavailability because they mostly eat cereals and fruits and not many eat meat or meat mixutres
  81. What bioavailability is used to sed Fe EAR for 1-8 years?
    Use 18% bioavailability
  82. What are the major components of Fe needs for children 9-18?
    • Basal Fe losses
    • Increase in hemoglobin mass
    • Increase in tissue (non-storage Fe)
    • Menstrual Fe losses in adolescent girls
    • No provision for the development of Fe stores after early childhood
  83. What is the EAR for iodine for children 1-8 years?
  84. What is the AI for fluoride?
    • 0.05mg/kg/day
    • Recommended for all ages >6 months
    • Protection against dental carries
  85. What is enamel fluorosis?
    • Caused by Fe ingestion during the pre-eruptive development of the teeth
    • After enamel has completed its pre-eruptive maturation--> no longer susceptible (by 8 years of age)
    • Milder forms of fluorosis: white opaque patches, often most apparent on the edges of teeth (snow capping)
    • Preeruptive maturation of the crowns of the anterior permanent teeth