Infant Feeding: Human Milk and Formula Joan C Zerzan MS RD CD

1. Infant Feeding: Human Milk and Formula Joan C Zerzan MS RD CD

2. Feeding Recommendations • Considerations • Growth in infancy • Physiology of infancy • GI • Renal • Infant Development • Nutrient requirements • Programming • Health and prevention

3. Feeding Recommendations • Nutrient needs • Programming • Health, development, and prevention

4. Considerations • Coordinated sucking and swallowing • Gastric emptying • Intestinal motility • Secretions: salivary, gastric, pancreatic, hepatobiliary • Enterocyte function in terms of enzyme synthesis, absorption, mucosal protection • Metabolism of products of digestion and absorption • Expulsion of undigested waste products

5. Physiology - GI Maturation

6. 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

7. 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

8. Gut Hormones • Gastrointestinal peptides are found in venous cord blood at birth in levels similar to those of fasting adults • In fetal distress a number of gut peptides are elevated which might account for passage of meconium • With enteral feeding levels of gut hormones (motilin, neurotensin, GIP (gastric inhibitory peptide), gastrin, enteroglucagon, PP - pancreatic polypeptide, rise rapidly

9. Choice of breast or formula feeds Enteric intake (induces epithelia hyperplasia and stimulates production of microvillous enzymes) Early enteral feeding (enteral feeding is strongly encouraged to promote GI function and differentiation) Gut Hormones Influenced By:

10. Possible Roles for Gut Hormones in Early Infancy

11. Pancreatic function is relatively deficient at birth and mature levels of pancreatic enzymes are not achieved until late infancy Pancreatic amylase activity increases after 4 to 6 monthsLipase levels do not approach adult efficiency until about 6 months Pancreas

12. Protein Digestion

13. Carbohydrate Digestion

14. Fat Digestion

15. Motility - Upper GI • Esophageal motility is decreased in the newborn • LES is primarily above the diaphragm • LES pressure is less for first months • Gastric Emptying may be delayed

16. Motility - Intestinal • Intestinal motility is more disorganized • Prolonged transit time in upper intestines may improve absorption of nutrients • Rapid emptying of ileum and colon may reduce time for water and electrolyte absorption and increase risk of dehydration

17. LES tone increases after 6 months and is associated with less reflux in most infants Gastric acid and pepsin activity do not reach adult levels until 2 years Pancreatic amylase increases by 6 months Retention of lactase activity is typical until 3 to 5 years. Fat absorption does not approach adult efficiency until about 6 months Lipase reaches adult levels by 2 years. Maturation in First Year

18. 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

19. Potential Renal Solute Load

20. 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

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

22. 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

23. 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 Programming by Early Diet

24. Allergies: Areas of Recent Interest • Early introduction of dietary allergens and atopic response • atopy is allergic reaction/especially associated with IgE antibody • examples: atopic dermatitis (eczema), recurrent wheezing, food allergy, urticaria (hives) , rhinitis • Prevention of adverse reactions in high risk children

25. Allergies: Infancy • Increased risk of sensitization as antigens penetrate mucosa, react with antibodies or cells, provoking cellular response and release of mediators • Immaturities that increase risk: • gastric acid, enzymes • microvillus membranes • lysosomal functions of mucosal cells • immune system, less sIgA in lumen

26. Allergies: IDDM • Theory: sensitization and development of immune memory to food allergens may contribute to pathogenesis of IDDM in genetically susceptible individuals. • Milk, wheat, soy have been implicated. • Breastfeeding and delay in non-milk feedings may be beneficial. • “There is little firm evidence of the significance of nutritional factors in the etiology of type 1 diabetes.” (Virtanen SM, Knip M. Am J Clin Nutr , 2003)

27. Feeding the Infant • Choices: • Human Milk • Standard Infant Formula (Cow, Soy) • Hypoallergenic (hydrolysates vs amino acid based • Other specialty formulas • Preterm • Post discharge formulas for preterm infants

28. Infant Feeding: Historical Perspective • Breast feeding • Human Milk Substitutes • Science, Medicine and Industry

29. “No two hemispheres of any learned professor’s brain are equal to two healthy mammary glands in the production of a satisfactory food for infants” - Oliver Wendell Holmes

30. Human Milk • Complements Immaturities of these systems • Promotes maturation • Epithelial growth factors and hormones • Digestive enzymes - lipases and amylase

31. Characteristics and Advantages of Human Milk • Low renal solute load • Immunologic, growth and trophic factors • Decrease illness, infection, allergy • Improved digestion and absorption • Nutrient Composition: CHO, Protein, Fatty Acid, etc • Cost • Other

32. Breast milk • Nutrient composition of breastmilk is remarkable for its variability, as the content of some of the nutrients change during lactation, throughout the bay, or differ among women, while the content of some nutrients remain relatively constant throughout lactation.

33. Human Milk • Colostrum • Higher concentration of protein and antibodies • Transitions around days 3-5 • Mature by day 10

34. Breastmilk and establishment of core microbiome • Definition: Full collection of microbes that naturally exist within the body. • Alterations or disruptions in core microbiome associated with chronic illness: Crohns disease, increased susceptability to infection, allergy, NEC, etc

35. Microbiome • Beneficial effect for the host: • Nutrient metabolism • Tissue development • Resistance to colonization with pathogens • Maintenance of intestinal homeostasis • Immunological activation and protection of GI integrity

36. Human milk and microbiome • Core microbiome established soon after birth • Core microbiome of breastfeeding infant similar to core microbiome of lactating mother • Components of breastmilk supporting establishment of microbiome • Prebiotics,probiotics

37. AAP: Breast milk and allergy • 1.Breast milk is an optimal source of nutrition for infants through the first year of life or longer. Those breastfeeding infants who develop symptoms of food allergy may benefit from: • a.maternal restriction of cow's milk, egg, fish, peanuts and tree nuts and if this is unsuccessful, • b.use of a hypoallergenic (extensively hydrolyzed or if allergic symptoms persist, a free amino acid-based formula) as an alternative to breastfeeding.

38. Protein: Predominant protein of human milk is whey & predominant protein in cow’s milk is casein • Casein: proteins of the curd (low solubility at pH 4.6) • Whey: soluble proteins (remain soluble at pH 4.6) • Ratio of casein to whey is between 40:60 and 30:70 in human milk and 82:18 in cow’s milk • some formulas provide more whey proteins than others

39. Distribution of Kcals

40. Allergies: Breastmilk • May be protective due to sIgA and mucosal growth factors • Maternal avoidance diets in lactation remain speculative. May be useful for some highly motivated families with attention to maternal nutrient adequacy.

41. AAP: Breastfeeding and the Use of Human Milk, 1997 • “Exclusive breastfeeding is ideal nutrition and sufficient to support optimal growth and development for approximately the first 6 months after birth….It is recommended that breastfeeding continue for at least 12 months, and thereafter for as long as mutually desired.”

42. AAP: Breastfeeding and the Use of Human Milk, 1997 • Human milk is the preferred feeding for all infants • Breastfeeding should begin as soon as possible after birth • Newborns should be nursed 8 to 12 times every 24 hours until satiety, usually 10 to 15 minutes per breast. (Crying is a late indicator of hunger.)

43. AAP: Breastfeeding and the Use of Human Milk, 1997 • Formal evaluation of breastfeeding by trained observers at 24-48 hours and again at 48 to 72 hours. • No supplements should be given unless a medical indication exists. • When discharged at <48 hours, should have FU visit at 2 to 4 days of age, assessment at 5 to 7 days, and be seen at one month.

44. AAP: Breastfeeding and the Use of Human Milk, 1997 • “Should hospitalization of the breastfeeding mother or infant be necessary, every effort should be made to maintain breastfeeding preferably directly or by pumping the breasts.”

45. AAP statement on breastfeeding (continued) • Supplements (water, glucose, formula) should be avoided (unless medically necessary). Pacifiers should also be avoided. • Exclusive breastfeeding is ideal for the first 6 months. Breastfeeding should continue for at least 12 months.

46. AAP statement on breastfeeding (continued) • In the first 6 months, water, juice and other foods are generally unnecessary. Vitamin D and iron may be needed. Fluoride should not be given during the first 6 months.

47. a.Breastfeeding mothers should continue breastfeeding for the first year of life or longer. During this time, for infants at risk, hypoallergenic formulas can be used to supplement breastfeeding. Mothers should eliminate peanuts and tree nuts (eg, almonds, walnuts, etc) and consider eliminating eggs, cow's milk, fish, and perhaps other foods from their diets while nursing. Solid foods should not be introduced into the diet of high-risk infants until 6 months of age, with dairy products delayed until 1 year, eggs until 2 years, and peanuts, nuts, and fish until 3 years of age.

48. Formula • Human Milk Substitutes • History • Regulation • Composition and indications

49. Formula Composition • Breast Milk as “gold standard” • Attempt to duplicate composition of breast milk • ? Bioactivity, relationship, function of all factors present in breast milk • ? Measure outcome: growth, composition, functional indices • Examples: DHA/ARA, Prebiotics and Probiotics • Evaluation: growth, composition, functional indices, other measures of safety and efficacy

50. Formulas containing hydrolysed protein for prevention of allergy and food intolerance in infants (2006) • There is no evidence to support feeding with a hydrolysed formula for the prevention of allergy compared to exclusive breast feeding. In high risk infants who are unable to be completely breast fed, there is limited evidence that prolonged feeding with a hydrolysed formula compared to a cow's milk formula reduces infant and childhood allergy and infant cow’s milk allergy. In view of methodological concerns and inconsistency of findings, further large, well designed trials comparing formulas containing partially hydrolysed whey, or extensively hydrolysed casein to cow's milk formulas are needed.