Infant Nutrition

Ala K. Shaikhkhali, MD Maria Mascarenhas, MD The Children’s Hospital of Philadelphia Reviewed by Sandeep Gupta, MD of the Professional Education Committee Infant Nutrition

Objectives • Normal growth patterns in infancy • Nutritional requirements of healthy term infants* • Macronutrients • Micronutrients • Benefits of human-milk • Practical guidelines for complementary feeding • Summary

Case Presentation • A mother brings in her 2 month old healthy term infant who is exclusively breast fed for a well visit How would you answer these nutritional questions: • Can she eat cereal now? • Mom heard that human-milk has less iron than formula, should the baby be on an iron supplement? • What about other supplements? • How fast should she be growing? • When will she double, triple her birth weight?

Growth Patterns in Infancy

Growth Patterns in Infancy Fun Fact: If a person who was born 8 lbs. and 20 in. at birth continued growing at the same rate as he does the first year, by the time he reached 20, he’d be 25 ft. tall and weigh nearly 315 lbs! • The first year of life is a period of very rapid growth - Healthy 1 month old gains~ 1 cm/week and 20-30 g/day - By 12 months of age gains 0.5 cm/week and 10 g/day • Average newborn weight is 3.5 kg, weight is doubled by 4-6 months and tripled by 12 months • Nutrition during infancy can influence risk factors for disease in adult life

Growth Charts • April 2006 WHO international growth charts** • Growth standard – describe growth of healthy children in optimal conditions (e.g. exclusive breastfeeding for 4 mo, continued to 12 mo) • Includes children 0-20 yrs • AAP recommends using WHO growth charts between 0-24 mo • May 2000 Chronic Disease Prevention and Health Promotion and Center for Disease Control* • Growth reference –how children grew in a particular place and time • Includes children 0 to 20 years of age • AAP recommend susing CDC growth charts between 2 and 20 yrs • Both growth charts include • Weight, length/height, head circumference, body mass index for age Normal growth reflects nutritional status and overall wellbeing; poor growth is always a cause for concern and should be evaluated promptly

Development of Feeding Abilities • Neonates have instinctive sucking reflexes • Things touching the infant’s palate (nipple or finger) will trigger the sucking reflex WHO recommends exclusive breast feeding for children until 6 months of age, followed by introduction of soft complementary foods with continued breast feeding At one year, infants can chew soft foods and swallow easily

Development of Renal Capacity Early in infancy, high protein load will cause renal overload and osmotic diuresis leading to dehydration The kidneys of a healthy term infant can excrete urea, sodium, and other solutes load that is present in human-milk or infant formula

Summary • The first year of life is a period of very rapid growth • Suboptimal growth is always a cause of concern • Infants have limited gastrointestinal and renal capacities • human-milk or iron-fortified formula should be the sole source of nutrition during the first 4-6 months of life • Physiological changes in the gut enable the infant to progress from digesting only milk to digesting complex foods by one year

Breast Feeding and Infant Formula

Breast Feeding • AAP recommends human-milk as the feeding of choice for infants whenever possible* • Successful breast feeding require a supportive environment for the mother • Nutrient needs of term infants from birth to 6 months of age are met with human-milk as a source of exclusive nutrition (with few exceptions)** • Success of breast feeding is demonstrated when infant has feedings 8-12 times per day, at least 6-8 wet diapers, regular stools, and growth along established growth curves • On average human-milk provides 20 calories/oz

human-milk vs. Infant Formula • Benefits of breast feeding over infant formula are well established: • Enhanced motility and maturity of the GI tract • Maternal infant bonding • Monetary saving • Facilitated fat, protein, and carbohydrate digestion and absorption • Passive immunity • Improved cognitive development • Decreased incidence of respiratory and GI disease • Further potential benefits are decreased risk of overweight, cardiovascular disease, and ? Type I DM

Infant Formula • When human-milk is not available, iron fortified infant formula is the appropriate alternative • There are continued efforts to evolve infant formula to be closer to composition of human-milk • Addition of DHA and ARA* is a recent example • Multiple studies in term and preterm infants showed significantly lower levels of DHA and ARA in RBC of infants who are formula fed • Some studies suggested short term improvement in vision and cognitive functions

Nutritional Requirements of Healthy Term Infants • Nutrient requirements for first 6 months are based on composition of human-milk • From 6 months to one year of age, RDA assume the composition of infant formula and increasing amounts of solid food

Macronutrients • Energy • Fluid • Carbohydrate • Fat • Protein

Energy Requirements • Expressed per unit of body weight, estimated energy requirements of a normal newborn is more than a normal adult • 80-110 kcal/kg/day vs. 20-35 kcal/kg/day in adults • Reflection of higher metabolic rate and energy needs for growth and development • Studies show that infants consume markedly higher energy intakes during the early months of life • Data also show that formula-fed infants consume more energy than breast-fed infants* • Gender differences are small but consistently present

Fluid Requirements • Necessary to replace losses (skin, lungs, feces, and urine) and for growth • human-milk and infant formula* provide ~ 89 ml of water in each 100 ml • Fluid needs: • 1 to 10 kg: 100 mL/kg/day

Carbohydrates Comprise 35 to 65% of total energy intake of term infants Usually as disaccharides or glucose polymers Glucose is the principal nutrient the neonatal brain utilizes Inadequate carbohydrate intake can lead to hypoglycemia, ketosis, and excessive protein catabolism

Fat • American Academy of Pediatrics recommends 30-55% of total energy be from fat and 2.7% be of linoleic acid • Adults should consume ~20-35% of energy from fat • Fat serves many roles: • A concentrated source of energy • Carries fat- soluble vitamins • Provides essential fatty acids • Important for brain and organ growth • Essential fatty acids are precursors for synthesis of prostaglandins and have other essential functions

Protein • AAP recommends that 7-16% of total energy be from protein or 1.6-2.2 g/kg/day • Protein provides nitrogen and amino acids • Synthesis of tissues, enzymes, hormones, and antibodies that regulate and perform physiologic and metabolic functions • Excess dietary proteins are metabolized for energy • Producing urea that increases the renal solute load, water requirements, and the risk of dehydration • Healthy term infants may grow well with a protein intake (from human-milk) slightly below 1.6 g/kg/day

Protein • Protein in most commercial infant formulas typically comes from cow milk • Cow’s milk based infant formula whey/casein ration of 20:80 • human-milk whey/casein ration is ~70:30 • Some recently developed formulas have a ratio 60:40 • The curd formed from whey in an acidic stomach is soft, easily digestible, and emptied quickly

Protein • Other protein sources in infant formula include • Soy protein • Protein hydrolysates • Free amino acid formulas are also available for infants with cow’s milk protein allergy who are unable to tolerate protein hydrolysates

Micronutrients In this section, we will discuss select vitamins and minerals that are pertinent to infant nutrition in board review related conditions Others are beyond the scope of this talk

Iron Unless mother has iron deficiency, term infants are usually born with iron stores enough for the first 6 months human-milk contains less iron than formula, but that iron is more bioavailable- so breast fed infants should not need iron supplementation routinely After the age of six months, iron content in human-milk is no longer enough and complementary foods should include iron (fortified cereal, meat)

Vitamin D Human-milk vitamin D content is low, breast fed infants should receive vitamin D supplementation at 400 IU daily Formula fed infants who receive a minimum of 1000 ml daily do not need vitamin D supplementation Risk factors for vitamin D deficiency: dark skin color, maternal vitamin D deficiency, and recommended lack of direct sun exposure <6 months of age Vitamin D deficiency can result in metabolic abnormalities and rickets

Fluoride • From birth to 6 months, infants need very little fluoride and are at risk of fluorosis with excessive intake • Human-milk contains very little fluoride and there is no risk of fluorosis • In formula fed infants, it is recommended to use ready to feed formula or water with low mineral content (purified, distilled, etc) • Infants above 6 months of age should receive fluoride supplementation only if they live in areas with non-fluoridated water

Folate/Vitamin B12 & Vitamin K • Infants of vegan mothers who are breast fed should be monitored for vitamin B12 deficiency • Folate deficiency is a risk in infants receiving large amounts of goat milk or powdered milk • The sterile digestive tract of newborn infants does not contain vitamin K-producing bacteria and they require a dose of vitamin K at birth • A newborn has a limited capacity for nutrient interconversion, which makes some nutrients conditionally essential

Complementary Feeding • Complementary food provides micronutrients that infants beyond 6 months of age need • Assess physical and psychological readiness for adding food • Introduce one new food every three days • Rice cereal is often introduced as the first feeding • Introducing meat early provides a rich source of iron and zinc • Repeated exposure may be necessary before acceptance

Complementary Feeding • By 9 months can add finely chopped and finger foods • 12 months infants can chew and progress to table food • Avoid choking hazards* • Frequency of meals • 6-8 months: two-three daily • 9-12 months: three-four daily • One or two snacks be added • Juice is not a necessary component of diet and should be limited

Summary • Breastfeeding is the normal and by far the preferred method of feeding infants • Exclusive breastfeeding is recommended for the first 6 months of life • Supplemental vitamin D is recommended for breastfed infants (400 IU daily) • When a mother is unable to breastfeed, iron fortified infant formula is the only acceptable alternative • First complementary foods should be iron-rich. • Routine growth monitoring is important to assess infant health and nutrition

Back to Our Case A mother brings in her 2 month old healthy term infant who is being exclusively breast fed for a well visit How would you answer these nutritional questions: • Can she eat cereal now? • Mom heard that human-milk has less iron than formula, should the baby be on an iron supplement? • What about other supplements? • How fast should she be growing? • When will she double, triple her birth weight?

References AAP Pediatric Nutrition Handbook Conn’s Current Therapy Nutrition in Medicine http://www.nutritioninmedicine.net/portal/ Heinberger Handbook of Clinical Nutrition Use of World Health Organization and CDC Growth Charts for Children Aged 0--59 Months in the United States FROM THE AMERICAN ACADEMY OF PEDIATRICS Prevention of Rickets and Vitamin D Deficiency in Infants, Children, and Adolescents Nutrition for Healthy Term Infants: Recommendations from Birth to Six Months A joint statement of Health Canada, Canadian Pediatric Society

Infant Nutrition