Formula choices and composition

The ideal food for the term neonate is breast milk. Although not fully nutritionally adequate for the extremely premature infant, preterm breast milk offers advantages over any synthetic formula and should be fed to premature infants whenever possible. Premature infants who have reached full feeds on breast milk should receive a human-milk fortifier to increase their caloric, protein, and mineral intake.

All postpartum mothers whose infants are in the NICU should be asked about providing breast milk for their infants. Although it is important not to add undue stress to new mothers with sick babies, mothers of VLBW infants should be made aware of the advantages of breast milk. Even if they were not planning on breastfeeding, many mothers are willing to pump breast milk for their sick premies; and they should be encouraged to do so.

If mothers are unable to provide breast milk for their infants, the following should serve as a guide for choosing an infant formula:

            Standard cow’s milk-based term formulas include Enfamil Lipil with iron, Similac with iron, and Similac Advantage.  These formulas all provide 20 kcal/oz.  Enfamil Lipil and Similac Advantage contain added DHA and ARA, very-long chain polyunsaturated fatty acids which are abundant in breast milk. LCPUFAs are thought to be important for early neural and retinal development.  Mead Johnson research suggested that Enfamil Lipil offered developmental advantages over Enfamil (no longer available), while Ross research did not find significant benefit to adding DHA/ARA to Similac.

References:

Auested N, et al. Growth and Development in Term Infants Fed Long-Chain Polyunsaturated Acids: A double-masked, randomized, parallel, prospective, multivariate study. Pediatrics 2001; 108:372-381.

Birch EE, et al. A randomized controlled trail of long-chain polyunsaturated fatty acid supplementation of formula in term infants after weaning at 6 weeks of age, American Journal of Clinical Nutrition 2002; 75: 570-80.

American Academy of Pediatrics. “Formula Feeding of Term Infants.” Pediatric Nutrition Handbook, 4^th ed. 1998. pgs. 29-42.

Aiges H. Formulae Odds and Ends. Pediatrics in Review 1997; 18: 84-5.

Enfamil Premature Formula (EPF) and Similac Special Care (SSC) are both 24 kcal/oz formulas designed to nourish infants < 1800g birthweight. These formulas provide an increased caloric density, more protein, and more calcium and phosphorus to meet a growing premature baby’s needs. The quality of the nutrients in these formulas differs from term formulas as well. Preterm formulas include glucose polymers or corn syrup as the source of carbohydrate for premies who have developmental lactase deficiency, and use MCT oil as a fat source since premies have immature digestive processes for long-chain triglycerides.

Both EPF and SSC now contain added DHA and ARA, long-chain PUFAs found in breast milk and thought to be important in neural and retinal development.  Research suggests that the addition of DHA/ARA to these formulas may improve infant visual acuity and cognitive outcomes.

Feed EPF or SSC to premature infants < 1800g and < 34 weeks postconceptual age.

References:

O’Connor D, et al. Growth and Development in Preterm Infants Fed Long-Chain Poyunsaturated Fatty Acids: A prospective, randomized controlled trial. Pediatrics 2001; 108: 359-371.

Innis SM, et al. Docosahexaenoic acid and arachidonic acid enhance growth with no adverse effects in preterm infants fed formula. J Pediatr 2002; 140: 547-54.

Transitional formulas

Enfacare 22 and Similac NeoSure are 22 kcal/oz transitional formulas designed for the premature infant > 32 - 34 weeks PCA or the SGA/LBW term infant. Growing former micropremies continue to need additional calories, protein, and calcium for optimal nutrition for several months after their NICU discharge. However, long term feeding of premature formulas can lead to the ingestion of excessive vitamins and minerals. Therefore, the transitional formulas are designed as post-discharge nutrition to provide these infants with appropriately increased amounts of calories, protein, and calcium for the first 6 to 12 months of life outside the NICU.

Both Enfacare 22 and Similac NeoSure now contain added DHA and ARA, long- chain PUFAs found in breast milk and thought to be important in neural and retinal development.

Start some preterm infants (>32 - 34 weeks EGA and >1800g ) on a transitional formula.

References:

Lucas A, et al. Randomized trial of nutrient-enriched formula versus standard formula for postdischarge preterm infants. Pediatrics 2001; 108: 703-11.

Carver JD, et al. Growth of preterm infants fed nutrient-enriched or term formula after hospital discharge. Pediatrics 2001; 107: 683-9.

O’Connor D, et al. Growth and Development in Preterm Infants Fed Long-Chain Poyunsaturated Fatty Acids: A prospective, randomized controlled trial. Pediatrics 2001; 108: 359-371

The elemental formulas include: Pregestimil, Alimentum, Nutramigen, and Neocate. The carbohydrate, protein, and fat components of these formulas are broken down into simplified forms to ease digestion and absorption. Elemental formulas are often used in post-GI surgical patients to initiate feeds. They are also used in patients with formula intolerances, particularly cow’s milk protein intolerance, and in patients with malaborption.

Pregestimil, Alimentum, and Nutramigen all contain a casein hydrolysate as the protein constituent. These formulas also use glucose polymers, sucrose, starch, and/or corn syrup as the carbohydrate source rather than lactose.

Neocate contains an even more elemental protein source in the form of L-amino acids for the rare infant who is unable to tolerate the small peptides in casein hydrolysate. Neocate’s nitrogen supply includes free glutamine, which is the preferred fuel of proliferating enterocytes and has been shown to improve mucosal integrity in adult and animal models.

Whereas these formulas provide adequate nutrition for term infants, they provide inadequate amounts of calcium to nourish premature infants long term.

Portagen is a formula whose fat source consists mostly (85%) of medium-chain triglycerides which can be absorbed directly in the small intestine and causes minimal burden to the lacteals, lymphatics, and thoracic duct. This formula is chiefly used in patients with lymphatic leakage, for ex. chylothorax.

In April 2002, an outbreak of Enterobacter sakazakii infection, including a fatal case of meningitis in a preterm neonate, was reported in association with a batch of contaminated Portagen powder.  This event added to several other similar occurrences worldwide led the CDC to advise clinicians to be aware of the potential risk for infection from use of non-sterile powdered formula in premature and debilitated neonates. The FDA and ADA both issued a statement that “powdered infant formulas should not be used in neonatal intensive care settings unless there is no alternative available.”  The potential risks and benefits of prescribing Portagen or any other formula that is available only in non-sterile powdered form must be carefully weighed by the clinician for each individual patient.

Reference:

CDC. Enterobacter sakazakii infections associated with the use of powdered infant formula-Tennessee, 2001. MMWR 2002; 51(14): 298-300.

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5114a1.htm

Tubman TRJ, Thompson SW. Glutamine supplementation for prevention of morbidity in preterm infants. Cochrane Database of Systematic Reveiws.

http://www.nichd.nih.gov/cochraneneonatal/tubman/tubman.HTM

Prosobee and Isomil are formulas designed for term infants that use soy protein rather than cow’s milk protein. They also replace the carbohydrate lactose with sucrose and corn syrup solids. These formulas may be tried in patients with a family history or symptoms of cow’s milk protein intolerance, but 40% of babies with true cow’s milk sensitivity will also be sensitive to soy and should be placed on an elemental formula. Soy formulas may be used in patients with galactosemia or with transient lactase insufficiency (often secondary to gastroenteritis.)   These formulas do not provide adequate calories or protein for premature infants.  They also contain phytates which decrease calcium and phosphorus absorption; and they do not contain carnitine.

Highly specialized formulas are available for infants with inborn errors of metabolism who require unusual amino acid intakes. These formulas will be recommended by the Pediatric Genetic/Metabolic specialist. The Pediatric Metabolic nutritionist can help obtain these formulas.

Similac PM 60/40 is also a specialized formula used almost exclusively in infants with renal failure to minimize their renal phosphate load. It may also be used in rare infants with pathologic late neonatal hypocalcemia.

Pedialyte is an electrolyte-containing dextrose solution originally designed as oral rehydration therapy for infants and children with diarrhea and dehydration. Pedialyte may be used in the nursery as an initial fluid to test GI tolerance in post-op patients or babies recovering from NEC or ileus.

Pedialyte is essentially D2.5W with 45 meq/L Na and 20 meq/L K. (The anions are chloride (35 meq/L) and citrate (30 meq/L).) It has an osmolarity of 250 mOsm/L and provides 10 kcal/oz.

FORMULA COMPOSITIONS

Nutrient

Energy

(kcal/oz)

Protein

(g/dL)

Carbohydrates

(g/dL)

Calcium

 (mg/dL)

Phosphorus

 (mg/dL)

Sodium

 (meq/dL)

Potassium

 (meq/dL)

Iron

 (mg/dL)

Osmolarity

 (mOsm/L)

References:

American Academy of Pediatrics. "Formula Feeding of Term Infants." Pediatric Nutrition Handbook, 4^th ed. 1998. pgs. 29-42.

Aiges H. Formulae Odds and Ends. Pediatrics in Review 1997; 18: 84-5.

Tubman TRJ, Thompson SW. Glutamine supplementation for prevention of morbidity in preterm infants. Cochrane Database of Systematic Reveiws.   http://www.nichd.nih.gov/cochraneneonatal/tubman/tubman.HTM

Young TE, Mangrum OB. Neofax 2001: A Manual of Drugs Used in Neonatal Care, 14^th ed. Acorn Publishing. Pgs. 209-244.