Bottle Delivery, Not Milk Type, Linked to Infant Weight Gain

Joanna Broder

May 07, 2012

May 7, 2012 — Babies fed by bottle are likely to gain more weight than babies fed at the breast, according to results from a new study published in the May issue of the Archives of Pediatric & Adolescent Medicine.

Ruowei Li, MD, PhD, from the National Center for Chronic Disease Prevention and Health Promotion; Division of Nutrition, Physical Activity, and Obesity, Centers for Disease Control and Prevention, Atlanta, Georgia, and colleagues analyzed early growth patterns of babies fed breast milk by breast compared with by bottle and also looked at infants who drank formula by bottle.

The researchers note that there are various hypotheses for why breast-feeding could be protective against childhood obesity. "In contrast to infants fed at the breast who may need to actively suckle, formula-fed infants are more likely to be passive in the feeding process, and caregivers' control might undermine infants' capability for self-regulation to balance energy intake against internal cues of hunger and satiety," the authors write. "Theoretically, feeding babies with expressed breastmilk could increase infant weight gain because it is fed by bottle."

Using a consumer mail panel to recruit pregnant women between May 2005 and June 2007, 1899 mother–infant pairs were recruited. The mothers completed surveys on their infants' weight gain from birth to age 1 year. Each participant reported at least 3 weight measurements during their baby's first year.

The 3 main exposure variables for this study were milk feeding category, percentage of milk feedings given as breast milk, and percentage of milk feedings given by bottle. From these feedings, "[s]ix mutually exclusive feeding categories and proportions of milk feedings given as breast-milk or by bottle," were established.

Compared with strictly breast-fed infants, babies who exclusively bottle-fed gained 71 or 89 g more per month when fed either nonhuman milk only (P < .001) or expressed human milk only (P < .02), respectively. But, "they gained only 37 g more per month when fed both expressed human milk and nonhuman milk (P = .08)."

The researchers also determined that babies who breast-fed and drank expressed human milk from bottles gained weight in a similar manner to infants who exclusively breast-fed, whereas infants who both breast-fed and drank from bottles of nonhuman milk gained 45 g more per month (P < .001), suggesting that "supplementing breastfeeding with expressed breastmilk would be preferable to supplementing breastfeeding with nonhuman milk."

The authors conclude that there really is no debate on the healthiest feeding mode for infants: "Feeding at the breast needs to be the first feeding choice for babies," they write. When it is not feasible to breast-feed, a good compromise is to pump and supplement the baby's diet with expressed breast milk, they say, but add that "special attention is needed for infants' internal feeding cues while bottle-feeding."

Counseling About Bottle vs Breast Feeding: Must Weigh All Factors

"This finding suggests that infants fed breast milk from the bottle consume more breast milk than they would if they were fed from the breast," note Robert Whitaker, MD, and Jeffrey Wright, MD, in an accompanying editorial. "However, in this nonexperimental study, milk intake was not measured."

Dr. Whitaker is a professor of public health and pediatrics at Temple University in Philadelphia, Pennsylvania, and Dr. Wright is an associate professor of pediatrics at the University of Washington School of Medicine in Seattle.

Breast-feeding might protect against obesity by preventing overfeeding, "suggesting that breastfeeding, rather than breast milk, protects against later obesity," the editorialists write.

Dr. Whitaker and Dr. Wright suggest that breast-feeding can be challenging and that some women will turn to bottle feeding at least in part to meet the challenges.

"Using a bottle can help mothers meet multiple work demands, paid and unpaid, by allowing others to help feed the infant," they write.

The editorialists encourage pediatricians to be sensitive to mothers: "Pediatricians should deliver their expert advice with empathy, being mindful of the gap that always exists for parents between doing what is ideal for their children and doing what is possible."

The Infant Feeding Practices Study II was supported by the US Food and Drug Administration, US Centers for Disease Control and Prevention, Office of Women's Health, National Institutes of Health, and Maternal and Child Health Bureau in the US Department of Health and Human Services. Dr. Whittaker's research is supported by the National Institutes of Health. The authors and the editorialists have disclosed no relevant financial relationships.

Arch Pediatr Adolesc Med. 2012;166:431-436.


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