Nutrition

The short answer is “Yes” and “No”! Infant formulas are in groups, and there may be a big difference between the groups. But within each group, each company has one, or several, products and these may not be that much different from one another. Think about soft drinks: Cola products are quite different from orange drinks, but among colas, Coke® vs. Pepsi® are not that different (although the companies will say they are!!) Infant formulas can be grouped into major categories:

Preterm: These formulas are intended for babies <200gm, 2000gm or >35 weeks, preparing for discharge. Late preterm infants (34 – 36 weeks) may also benefit. Recommendations for how long to keep your baby on a transitional formula vary. Some physicians recommend until almost a year of chronologic age, whereas others think they are of no benefit.

Transitional: The same companies that make premie formulas make “transitional” formulas. Typically 22 cal/oz, they have a bit less calcium and phosphorus than the preterm formulas, but more than regular term infant formula. They are marketed for the ex-premie that is now >2000gm or >35 weeks, preparing for discharge. Late preterm infants (34 – 36 weeks) may also benefit. Recommendations for how long to keep your baby on a transitional formula vary. Some physicians recommend until almost a year of chronologic age, whereas others think they are of no benefit.

Term: The typical term formula is 20 cal/oz, and tries very hard to replicate human milk with its micro and macro-nutrient composition, casein:whey protein ratio, and other obscure components like "prebiotics" or "DHA-ARA." In the United States, any term formula that is not soy-based uses cows-milk proteins as its protein source, and cannot approach the benefits conferred by feeding human milk. Term formulas, now, are appearing in many subtle forms. Similac® for example, offers Similac Sensitive for Spit Ups, Similac Sensitive for gas, Similac Total for multiple feeding problems. Then there's Similac for Supplementation, for the breastfeeding mother who wishes to supplement. The Enfamil® product line has a similar assortment. While each of these products is slightly different, none of them approximate human milk, so should not be considered equivalent feeding choices. For the mother who chooses not to provide breast milk, however, they provide the most suitable alternative available.

Specialty formulas: Babies with true nutritional medical issues benefit from formulas especially formulated to address the particular issue. One example are the “elemental” formulas – products that contain proteins already broken down into their most basic (aka “elemental”) form so that the baby’s digestive processes don’t have to do the work. Infant born with gastroschisis, omphalocoele, atresias that required major resection, or post-surgical NEC babies, may tolerate elemental formulas when human milk isn’t available. Many pediatricians use these formulas as a panacea for colic – and it works! Truth is, it doesn’t. Colic is self-limited, and by the time the pediatrician has marched through the chain of formulas, over a period of weeks, the colic self resolves. Because the elemental formula was the last in the progression, it is declared “the cure!” Elemental formulas smell TERRIBLE and taste worse. They are very expensive and do not contain the necessary components to adequately nourish a growing premature infant.

A Word about Lactose and Soy: Lactose is the form of sugar found in milk – ALL milk. In fact, human milk contains MORE lactose than cow’s milk!! Lactose is split by the enzyme lactase into two components: glucose and galactose. True lactose intolerance – congenital absence of lactase – is extremely rare – about 1:65,000. Many mothers complain that their babies are “lactose intolerant” and the formula companies oblige by manufacturing lactose-free formulas. These formulas derive their carbohydrate from corn sugar or table sugar, which do not yield galactose when digested. The full effects of galactose on the developing brain are unknown, but the myth regarding “lactose intolerance” in babies is mostly unfounded. Formulas vary in many ways from human milk which can contribute to feeding intolerance, and removing as the culprit a substance that appears less than in human milk lacks common sense. Soy formulas are similar. Human milk is high in whey and low in casein, whereas cow’s milk is the opposite. Casein is used to make white glue, and it may be the proteins rather than the sugars that contribute to feeding intolerance. Soy protein comes entirely from soybeans, so has neither whey nor casein. (It also has no lactose. The inborn error of metabolism, galactosemia, is the only true indication for a soy protein formula.) Soy protein is an “incomplete protein” for a preterm infant, as it lacks taurine, an essential amino acid for the growing infant. Absence of lactose also negatively affects calcium/phosphorus absorption as well as other speculative effects. Soy formulas are not recommended routinely for the preterm infant.

TPN stands for Total Parenteral Nutrition, and refers to the solution infused into your baby’s veins that provides nourishment when s/he is not feeding into his/her tummy. TPN is life-saving in the short term, and can provide all of the protein, carbohydrate, and fat, along with vitamins and minerals, needed to grow and develop. Technically, two solutions comprise TPN: 1) a yellow-colored liquid that has the protein, sugar, vitamins and minerals needed; 2) and a milky white liquid that is the fat. To be precise, the yellow liquid is actually called “Hyperalimentation” and the milky white stuff is called “IntraLipid.” Because the two solutions together provide the full spectrum of nutrition, the combination is called TPN.

Your care team specifies everyday what recipe is used to mix the TPN – and what goes into the solution is what your baby has to grow. If not enough of the substrates are provided, then your baby will either use up precious body stores, or will not develop optimally. If too much of something is provided, it may overstress your baby’s delicate metabolism or organ function, sometimes as to be life-threatening. Hospitals have elaborate mechanisms in place to prevent compounding and administration errors, but sometimes mistakes happen despite everyone’s best efforts.

The best measure of your baby’s normal development is a growth rate that matches fetal growth rates at your baby’s gestational age. Your baby should be weighed frequently, usually every day, and weight gain plotted on a standardized growth chart. While this measures overall body weight, it does not measure body composition, and there is new discussion among neonatologists that our babies may not be developing lean body tissue – muscle and bone – even though they are gaining weight. Some people call this “skinny-fat.”

Every day, from birth, your baby should be receiving at least 4gm/kg/day of protein, 17 gm/kg/day of carbohydrate, and 3gm/kg/day of fat. Total calories, from all sources, should be at least 120kcal/kg/day for older babies, and >135kcal/kg/day for tiny premies or those with increased needs such as lung or heart disease. Weight and head circumference should be charted weekly on the most recent standardized chart, using fetal growth curves as a reference.