(RxWiki News) It's often said that "breast is best" when it comes to feeding infants. However, a recent study found that it's possible the benefits of breastfeeding are not as dramatic as past studies may have shown.
Breastfeeding children for at least their first six months of life is recommended by US and world medical authorities.
Yet, when a team of researchers recently compared siblings within the same families, those who were breastfed did not necessarily do any better in a number of areas than those who were formula fed.
These areas included health outcomes, such as obesity, and behavioral or intellectual outcomes, such as math and vocabulary skills.
"Try to breastfeed your baby for at least six months."
This study, led by Cynthia G. Colen, PhD, MPH, of the Department of Sociology at Ohio State University, sought to learn more about the benefits of breastfeeding compared to formula feeding.
The researchers used two data sets. One came from a long-term study of men and women who were between the ages of 14 and 22 in 1979. Then, the researchers gathered data from the children born to the women in that 1979 group between 1986 and 2010.
These children were aged 4 to 14 at the time the second set of data was collected.
This study included 8,237 children from the two studies combined and their siblings. Among their siblings were 7,319 brothers and sisters who had been fed the same way as the original participants. Then 1,773 siblings were included who had been fed differently than the original participants.
In other words, if the original participants had been breastfed, then their siblings in the group of 1,773 had been formula fed, or vice versa.
The researchers considered 11 different characteristics among the children:
- weight (measured by body mass index, or BMI)
- parental attachment (having a secure emotional relationship between the parent and the child)
- appropriate behavior
- reading recognition skills
- math skills
- intelligence (IQ)
- school performance
When the researchers looked at the data as a whole, comparing children who were breastfed to children who were formula-fed, they found that the breastfed children did better in a number of areas.
These areas included a healthier BMI, lower hyperactivity, lower obesity rates, better performance in school and better skills in math, reading recognition, identifying vocabulary and remembering numbers.
Then, the researchers looked only at the differences among the pairs of siblings in which one child had been breastfed and one child had been formula-fed.
In this analysis, there were no statistically identifiable differences between the children in terms of the outcomes studied except that breastfed babies appeared to have a higher likelihood of asthma.
However, it's not clear if the breastfed babies actually had more diagnoses of asthma or if this was a finding based on the mothers' reports that may not be reliable.
By comparing breastfed children with their formula-fed siblings, the researchers were able to better account for differences that might have resulted from different family structures or behaviors, different levels of parent education or household income and different races/ethnicities.
Past studies have already found that many of these factors influence which mothers breastfeed in the first place. Therefore, it has often been challenging to determine whether differences between breastfed and formula-fed children were a result of how they were fed or the other circumstances that were related to their mothers' feeding decisions.
This study's findings appeared to show that the effects of breastfeeding on a child's long-term outcomes were not much different than those for formula-fed children.
However, there are other potential benefits to breastfeeding, such as passing along disease immunity and benefits for the mother, which this study did not investigate.
This study's conclusion also differed from the conclusions of many other studies that did attempt to take into account differences such as family income, race/ethnicity and parental education.
Therefore, the question of long-term effects from breastfeeding, rather than formula feeding, need to continue to be studied.
"Science has shown the value of many of the compounds found in breast milk and over the last years manufacturers have added many of these compounds to the formulas," said Thomas Seman, MD, a pediatrician at North Shore Pediatrics in Danvers, Mass.
"The study seems fairly strong although the discussion does point out some weaknesses," he said. "However, it proves the fact that good nutrition from an early age is key to maximum development."
Dr. Seman noted that persisting with unsuccessful breastfeeding instead of using formula may actually lead to other concerns.
"In my experience, when a mom tries to breastfeed and cannot, either because she is stressed with her other obligations or she is unable to produce sufficient supply, the stress can be felt by the child," he said. "This can change the bonding and the child's experience with eating, satiety and comfort."
What is most important, he stressed, is that infants receive healthy nutrition.
"Once a mom realizes that the benefit of a relaxed meal is important for both her and her child, then the child becomes more relaxed and active, typically starts to gain weight better and are often more comfortable," he said. "The studies show the benefit of this good nutrition no matter what the source."
This study was published January 29 in the journal Social Science & Medicine. The research was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
No information regarding conflicts of interest was reported.