NEWS AND FEATURES
Copyright © 2014, The American Academy of Pediatrics
What pediatricians need to know about new low calorie/low protein formulas
Frank R. Greer, M.D., FAAP and Steven A. Abrams, M.D., FAAP
Infant formulas with lower energy density and lower protein content than those historically sold in the United States are being introduced this spring. This change follows the recent addition of novel components such as pre- and probiotics into some formulas.
As the number of formula choices increases and the selection process becomes more complicated, families may seek their pediatrician’s advice. Pediatricians, therefore, should be on alert for new formulas and be familiar with the research on formulas with varying amounts of energy and protein.
OBESITY A CONCERN
Because the risk of overweight is higher in formula-fed infants than breastfed infants, some support lowering the protein content and energy density of infant formulas (Koetzko B, et al. Adv Exp Med Biol. 2005;569:69-79; Timby N, et al. Am J Clin Nutr. April 2014, https://ajcn.nutrition.org/content/early/2014/02/05/ajcn.113.064295.abstract).
It has been reported that the intake of both protein and total energy in formula-fed infants exceeds that of breastfed infants. Limited evidence indicates that this difference is due primarily to the increased volume of intake in formula-fed infants compared to breastfed infants (Hester SN, et al. J Nutr Metab. 2012;2012:891201).
It also has been observed that the average energy density of formula is higher than that of breast milk — 67 kilocalories (kcal) per 100 milliliters (mL) of formula vs. 65.2 kcal per 100 mL in mature human milk. The average protein content in formula also is higher than that found in mature breast milk — 1.4 grams (g) vs. 1.3 ± 0.1 g per 100 mL (range 0.8 to 2.1 g per 100 mL) (Hester SN, et al. J Nutr Metab. 2012;2012:891201).
There are two important issues here. The first is whether the historically used protein content (1.4 g per 100 mL) and energy density (67 kcal per 100 mL) in formulas can be decreased safely. The second is whether such changes will meet the objective of decreased weight gain.
The minimal amount of protein in formula permitted by the Food and Drug Administration based on the Infant Formula Act is 1.2 g/100 mL (www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/InfantFormula/ucm136118.htm.) The Infant Formula Act does not specify a minimum energy density requirement for infant formulas. However, a minimum level of 63 kcal/100 mL is recommended in a 1998 report on nutrient requirements of infant formulas from the Life Sciences Research Office of the American Society for Nutritional Sciences (https://jn.nutrition.org/content/128/11/suppl/DC1).
RESEARCH ON NEW FORMULAS
Few studies have looked at the impact of both reduced protein and energy in formulas on growth in term infants.
A recently published randomized, controlled study from Sweden with approximately 70 infants per group compared two formulas — an experimental formula containing 60 kcal and 1.2 g of protein per 100 mL and a standard formula containing 66 kcal and 1.27 g of protein per 100 mL (Timby N, et al. Am J Clin Nutr. April 2014, https://ajcn.nutrition.org/content/early/2014/02/05/ajcn.113.064295.abstract). The study also included a comparative group of breastfed infants. The infants were randomized to the formulas at 3 weeks of age, and complementary foods were introduced between 4 and 6 months of age.
Somewhat surprisingly, there were no significant differences in growth parameters during the first year of life among the three groups of infants. However, the authors documented a significantly increased volume of formula intake in the infants on the lower energy and lower protein formula between 2 and 6 months of age. The authors concluded that these infants self-regulated their intakes to compensate for the lower amounts of energy and protein in the experimental formula.
The new formula recently marketed in the United States contains 1.3 g of protein per 100 mL and 63.3 kcal per 100 mL, roughly a 5% decrease compared to infant formulas historically used in the United States. However, no studies have evaluated the risks or benefits of decreasing protein content and energy density by this amount in U.S. infants.
ADVISING PARENTS
An important concern for pediatricians is that the U.S. Department of Agriculture requires that all routine (non-exempt) formulas used for the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) to deliver 67 kcal per 100 mL of formula. Since the WIC program accounts for slightly more than half of all of the formula consumed in the United States, the majority of U.S. infants would not be able to readily obtain newly released lower protein and energy dense formulas.
Some states may allow the new formula as a WIC prescription formula meaning a pediatrician would need to recommend it to WIC in writing. How each state will handle this has not been determined and may vary between states.
When advising parents on use of formulas with lower amounts of energy and protein, pediatricians must weigh the theoretical benefits of a 5% decrease in calories and protein against limited studies with no long-term outcome data to support the changes in ingredients. Neither parents nor pediatricians should assume that newer or more expensive products have health benefits for infants.
FOOTNOTES
Dr. Greer is former chair and Dr. Abrams is a member of the AAP Committee on Nutrition.