Infant nutrient needs

1. Infantnutrient needs Basis Approach Specific nutrients water energy protein fatty acids vitamin K Vitamin D Iron Fluoride

2. Basis of recommendations • Growth and development • Physiology • GI • Renal • Programming • Goals and objectives • Nutrient needs

3. Challenges • Strength of Evidence • Individual vs population • Public health approach • Individual genetics • Maternal-infant dyad • In utero endowment • Beliefs, values, choices • Relationship/nurture • Environmental factors

4. Physiology - GI Maturation

5. In utero • Fetal GI tract is exposed to constant passage of fluid that contains a range of physiologically active factors: • growth factors • hormones • enzymes • immunoglobulins • These play a role in mucosal differentiation and GI development as well as development of swallowing and intestinal motility

6. At Birth • Gut of the newborn is faced with the formidable task of passing, digesting, and absorbing large quantities of intermittent boluses of milk • Comparable feeds per body weight for adults would be 15 to 20 L

7. Limited ability to concentrate urine in first year due to immaturities of nephron and pituitary Potential Renal solute load determined by nitrogenous end products of protein metabolism, sodium, potassium, phosphorus, and chloride. Renal

8. Most normal adults are able to achieve urine concentrations of 1300 to 1400 mOsm/l Healthy newborns may be able to concentrate to 900-1100 mOsm/l, but isotonic urine of 280-310 mOsm/l is the goal In most cases this is not a concern, but may become one if infant has fever, high environmental temperatures, or diarrhea Urine Concentrations

9. Nutrient composition in early diet may have long term effects on GI function and metabolism Animal models show that glucose and amino acid transport activities are programmed by composition of early diet Animals weaned onto high CHO diet have higher rates of glucose absorption as adults compared to those weaned on high protein diet Barker Hypothesis: Association between BMI and chronic disease: HTN and cardiovascular, SGA/IUGR Programming by Early Diet

10. Goals and Objectives • Optimal growth and development • Individual health • Population Health • Prevention and Chronic Illness

11. Nutrients • Need • Guidelines • recommendations

12. Needs • Individual • Genetics • Adaptation • Environment • Behavior/activity • Choices, access, resources • other

13. Recommendations/guidelines • DRI: Dietary Reference Intakes • AI • UL • EER • AAP • Bright Futures • Start Healthy feeding guidelines

14. DRI: Dietary Reference Intakes periodically revised recommendations (or guidelines) of the National Academy of Sciences quantitative estimates of nutrient intakes for planning and assessing diets for healthy people AI: Adequate Intake UL: Tolerable Upper Intake Level EER: Estimated Energy Requirement

15. Approaches to Estimating Nutrient Requirements • Direct experimental evidence (ie protein and amino acids) • Extrapolation from experimental evidence relating to human subjects of other age groups or animal models • ie thiamin--related to energy intake .3-.5 mg/1000 kcal • Breast milk as gold standard (average [] X usual intake) • Metabolic balance studies (ie protein, minerals) • Clinical Observation (eg: manufacturing errors B6, Cl) • Factorial approach • Population studies

16. DRI: Dietary Reference Intakes expands and replaces RDA’s reference values that are quantitative estimates of nutrient intakes for planning and assessing diets for healthy people AI: Adequate Intake UL: Tolerable Upper Intake Level EER: Estimated Energy Requirement Comparison of individual intake data to a reference or estimate of nutrient needs

17. DRI’s for infants • Macronutrients based on average intake of breast milk • Protein less than earlier RDA • AAP Recommendations • Vitamin D: 200 IU supplement for breastfed infants and infants taking <500 cc infant formula • Iron: Iron fortified formula (4-12 mg/L), Breastfed Infants supplemented 1mg/kg/d by 4-6 months

18. Water

19. Water • Water requirement is determined by: • water loss • evaporation through the skin and respiratory tract (insensible water loss) • perspiration when the environmental temperature is elevated • elimination in urine and feces. • water required for growth • solutes derived from the diet

20. Water • Water lost by evaporation in infancy and early childhood accounts for more than 60% of that needed to maintain homeostasis, as compared to 40% to 50% later in life • NAS recommends 1.5 ml water per kcal in infancy.

21. Water Needs

22. Water • Individual needs • Renal concentrating ability • Solute in diet • Health • environment

23. Water • Water balance • RSL in diet • Water in • Water out • Renal concentrating ability

24. Renal solute load • Samuel Foman J Pediatrics Jan 1999 134 # 1 (11-14) • RSL is important consideration in maintaining water balance: • In acute febrile illness • Feeding energy dense formulas • Altered renal concentrating ability • Limited fluid intake

25. Water vs fluid • Concentrating formula decreases free water and increases RSL • What is the % water in 20 kcal/oz infant formula? • 90% • To achieve 100 ml/kg/d needs to consume at least 110 cc/kg/d

26. Energy

27. Energy Requirements • Higher than at any other time per unit of body weight • Highest in first month and then declines • High variability - SD in first months is about 15 kcal/kg/d • Breastfed infants many have slighly lower energy needs • RDA represents average for each half of first year

28. Energy Requirements, cont. • RDA represents additional 5% over actual needs and is likely to be above what most infants need. • Energy expended for growth declines from approximately 32.8% of intake during the first 4 months to 7.4% of intake from 4 to 12 months

29. Energy Partition in Infancy (kcal/kg/d)

30. Energy Intakes by Breastfed and Formula Fed Boys (kcal/kg)

31. EER • 0-3 months (89 x wt -100) + 175 • 4-6 months (89 x wt -100) + 56 • 7-12 months (89 x wt -100) + 22 • 13-35 months (89 x wt -100) + 20 • Equations for older children factor in weight, height and physical activity level (PAL)

32. 2002 Energy DRI

33. Protein • Increases in body protein are estimated to average about 3.5 g/day for the first 4 months, and 3.1 g/day for the next 8 months. • The body content of protein increases from about 11.0% to 15.0% over the first year

34. 2002 Protein DRI

35. 2002 Carbohydrate DRI

36. 2002 Fat DRI

39. Essential Fatty Acids • The American Academy of Pediatrics and the Food and Drug Administration specify that infant formula should contain at least 300 mg of linoleate per 100 kilocalories or 2.7% of total kilocalories as linoleate.

40. Essential Fatty Acids • The American Academy of Pediatrics and the Food and Drug Administration specify that infant formula should contain at least 300 mg of linoleate per 100 kilocalories or 2.7% of total kilocalories as linoleate.

41. LCPUFA DHA and ARA

42. LCPUFA: Background

43. LCPUFA: Background • Ability to synthesize 20 C FA from 18 C FA is limited. • n-3 and n-6 fatty acids compete for enzymes required for elongation and desaturation • Human milk reflects maternal diet, provides AA, EPA and DHA • n-3 important for neurodevelopment, high levels of DHA in neurological tissues • n-6 associated with growth & skin integrity

44. Formula supplementation with long-chain polyunsaturated fatty acids: are there developmental benefits? Scott et al. Pediatrics, Nov. 1998. • RCT, 274 healthy full term infants • Three groups: • standard formula • standard formula with DHA (from fish oil) • formula with DHA and AA (from egg) • Comparison group of BF

45. Outcomes at 12 and 14 months • No significant differences in Bayley, Mental or Psychomotor Development Index • Differences in vocabulary comprehension across all categories and between formula groups for vocabulary production.

46. Bayley Scales at 12 months

47. MacArthur Communicative Development Inventories at 14 Months of Age

48. Conclusion “We believe that additional research should be undertaken before the introduction of these supplements into standard infant formulas.”

49. PUFA Status and Neurodevelopment: A summary and critical analysis of the literature(Carlson and Neuringer, Lipids, 1999) • In animal studies use deficient diets through generations - effects on newborn development may be through mothering abilities. • Behaviors of n-3 fatty acid deficient monkeys: higher frequency of stereotyped behavior, locomotor activity and behavioral reactivity

50. Efficacy and safety of docosahexaenoic acid and arachidonic acid addition to infant formulas: can one buy better vision and intelligence?(Koo. J Am Coll Nutr. 2003 Apr;22(2):101-7) • “Functional benefits in particular visual or neural development from IF containing LCPUFA remains controversial.” • “Potential for excessive and/or imbalanced intake of n-6 and n-3 fatty acids exists with increasing fortification of LCPUFA to infant foods other than IF.”