ENTERAL NUTRITION MANAGEMENT NEWBORNS

ENTERAL NUTRITION MANAGEMENT
Energy
• With enteral nutrition, human milk and standard infant formulas (20 cal/oz) provide 67 cal/100 mL. In general, human milk is the preferred source of enteral nutrition because of its trophic and immunologic properties. Evidence is substantial that necrotizing enterocolitis is lower in preterm infants fed with breast milk.

• Higher caloric densities include 22 cal/oz and 24 cal/oz formulas. Formulas with caloric densities higher than 24 cal/oz should be used with caution, as they often have a very high renal solute load and can lead to dehydration.

Carbohydrate
• Lactose is the carbohydrate source in human milk and in most standard formulas given to term infants. Lactose provides 40-45% of the energy.

• In preterm infant formulas, lactose provides 50% of the carbohydrates and glucose polymers provide 50%. This is because of the lower intestinal lactase levels and relatively higher intestinal glycosidase levels in premature infants. The use of glucose polymers (rather than monosaccharides or disaccharides) also helps maintain a lower osmolality.

• Soy and lactose-free formulas use sucrose, maltodextrins, and glucose polymers as the carbohydrate sources.

Fat
• With enteral nutrition, approximately 50% of the energy is derived from fat. If more than 60% of the energy is derived from fat, risk of ketosis is increased.

• Medium-chain triglycerides can be absorbed without pancreatic lipase or bile salt emulsification. As a result, preterm infant formulas have a higher percentage of fat supplied as medium-chain triglycerides.

Protein
• Protein requirements of 1.8-2.2 g/kg/d are readily provided to term infants by human milk and standard infant formulas.

• Preterm infant formulas have a higher protein content to allow delivery of the necessary 3-3.5 g/kg/d.

Minerals, vitamins, and trace elements
• Calcium, phosphorous, and magnesium
o During the third trimester, accretion rates for calcium (120-150 mg/kg/d) and phosphorous (75-85 mg/kg/d) are higher than rates that can be provided in premature infants receiving human milk. As a result, a human milk fortifier is essential, and premature infants fed human milk must receive supplementation to minimize the risk of osteopenia of prematurity.
o Premature infant formulas have a much higher concentration of these minerals, which helps approximate the third trimester accretion rates in infants receiving these formulas.
o Human milk and term and premature infant formulas all provide amounts of magnesium adequate to meeting an infant's nutritional requirements if the infant is receiving at least 100 cal/kg/d.

• Iron
o To minimize the risk of iron deficiency anemia, all formula-fed term infants should receive iron fortified formulas. Breastfed term infants should receive supplemental iron beginning at age several months.
o Premature infants should be started on supplemental iron once they are receiving full enteral feedings regardless of whether they are fed human milk or premature infant formula.

• Vitamins and trace elements
o Full-term infants fed standard infant formula do not routinely require vitamin supplements, since adequate quantities of all of the vitamins are present in the formula.
o Full-term infants fed human milk should receive supplemental vitamin D to minimize the risk of osteopenia and rickets.
o Premature infants fed human milk without human milk fortifier should be started on a multivitamin supplement as soon as they are receiving full enteral nutrition.
o Premature infants receiving human milk with human milk fortifier or standard premature infant formulas should not routinely require additional vitamin supplements.

Special formulas
A number of special infant formulas are available to meet the very specific dietary needs of small groups of patients who cannot be maintained on standard term or premature infant formulas. These formulas include soy-based formulas, elemental formulas, and formulas with unique protein, fat, and carbohydrate content. As a result of the low calcium and phosphorous contents of soy-based formulas, they are not appropriate for premature infants. Specialty formulas are available for infants with galactosemia, phenylketonuria, short gut syndrome, and protein allergy, as well as many other conditions.