News Flash: Breastfeeding and Later Solid Food Introduction are Protective against Obesity in Young Children

A 2007 report from the CDC showed that 3 out of every 4 new mothers in the United States initiate breastfeeding. However, only 33% are exclusively breastfeeding at 3 months. That means 64% of babies nationally are at least partially formula-fed. (1) A 2011 study, that received widespread news coverage, now shows that formula-fed babies are at higher risk of obesity at age 3. Among those that are formula-fed and started on solid foods before 4 months of age, the risk of obesity at age 3 is even greater. (2)

Recommendations vs. Reality
Currently, 26% of infants in the US are introduced to solid foods before 4 months-of-age and, while the World Health Organization (WHO) and the American Academy of Pediatrics (AAP) Breastfeeding Section recommend introduction of solid foods at 6 months of age, many pediatricians (and even the AAP Committee on Nutrition) continue to endorse starting solids between 4-6 months of age. However, a recent study may provide more proof that starting solid foods before 4 months of age could have negative effects lasting into early childhood. (2)

Pediatrics recently published the results from a large study conducted at Harvard that compared age of solid food introduction (less than 4 months, 4-5 months or ≥6 months) and risk of later obesity in preschoolers. (2) Sixty seven percent of infants in the study were “breastfed” (defined as at least partly breastfeeding) at 4 months-of-age and 33% were “formula-fed” (defined as never breastfed or breastfed less than 4 months). Two factors were linked to increased obesity risk at age 3:

1. Early solid food introduction among babies who were never breastfed or were breastfed for less than 4 months - Those introduced to solids before 4 months-of-age had a 6-fold increase in odds of obesity at 3 years-of-age. Interestingly, early introduction of solid foods in babies who were at least partly breastfed for more than 4 months had no effect on later obesity, and moms who “breastfed” for longer than 4 months were less likely (8% compared to 33%) to start solid foods early compared to “formula-fed” babies and babies who breastfed less than 4 months. (2)

2. Breastfeeding Status - Breastfeeding status was also connected to obesity at age 3 years, with almost double the percentage of “formula-fed” babies obese compared to babies breastfed at least 4 months. (2)

What does all of this mean?
With 1/4 of babies in the US never breastfed and 1/2 breastfed for less than 4 months, delaying solid food introduction until after 4 months-of-age may be an important step towards decreasing obesity in young children. (2) Other studies also indicate that introduction of solid foods before 4 months of age is associated with rapid weight gain in infancy and higher body fat or weight in childhood. (3,4) Also, breastfeeding, even partly, for at least 4 months may be protective against early childhood obesity. (2) This is not to say that babies don’t reap added benefits when exclusively breastfed (such as reduced risk of gastrointestinal and respiratory illness, Sudden Infant Death Syndrome (SIDS) and allergies, to name a few)! (5) However, this particular study only compared breastfed (at least partly breastfed for at least 4 months) to formula-fed (breastfed less than 4 months or fed only formula) infants.

It’s also important to note that while it is recommended to delay solids until close to 6months-of-age, developmental signs of readiness for solid foods must still be observed in the infant before solid foods are introduced. For more information about what developmental signs to look for and which foods to feed first, click here.

Next time: Baby Behavior during illness

References:
1. CDC Breastfeeding Report Card –– United States, 2010. Web. 28 Mar. 2011.
2. Huh SY, Rifas-Shiman SL, Taveras EM, Oken E, Gillman MW. Timing of Solid Food Introduction and Risk of Obesity in Preschool-Aged Children. Pediatrics. 2011 Mar;127 (3):e544-51.
3. Baker JL, Michaelsen KF, Rasmussen KM, Sørensen TI. Maternal prepregnant body mass index, duration of breastfeeding, and timing of complementary food introduction are associated with infant weight gain. Am J Clin Nutr. 2004;80(6):1579-88.
4. Kim J, Peterson KE. Association of infant child care with infant feeding practices and weight gain among US infants. Arch Pediatr Adolesc Med. 2008;162(7):627-33.
5. Kramer MS, Kakuma R. The Optimal Duration of Exclusive Breastfeeding: A Systematic Review. WHO, 2002.