- A new study found that formula-fed babies were three times more likely to be overweight than exclusively breastfed babies.
- The study also found that, when it came to healthy infant weight gain, pumped breast milk in bottles was not as beneficial as direct breastfeeding.
- This may be because refrigerating or freezing changes components of breast milk, or because feeding at the breast helps babies self-regulate their intake, a study author told INSIDER.
A new study shows that breast milk in a bottle doesn’t have the same benefits as breast milk directly from the breast – at least when it comes to healthy infant weight gain.
The findings were published Monday in the journal Pediatrics, CNN reported.
Researchers analysed 2,553 mother-and-infant pairs enrolled in the long-term CHILD Study to see how feeding practices affected the babies‘ weight gain during the first year of life. Babies need to gain weight as they grow, of course, but excessive or rapid weight gain in infancy may increase the odds of obesity later in life, the study authors wrote.
“One in three children are overweight or obese, and most of them have reached that state before they even enter preschool,” study author Dr. Meghan Azad, a research scientist at the Children’s Hospital Research Institute of Manitoba, told INSIDER. “We know that it starts really early. So [studying] infant feeding is a good place to start.”
In the new study, breastfeeding was associated with lower BMI and a lower risk of rapid weight gain – and this benefit got stronger with longer and more exclusive breastfeeding. At 12 months old, formula-fed babies were three times more likely to be overweight than exclusively breastfed babies, Azad explained.
There’s already some existing evidence to support this result. One previous analysis found that breastfed infants had a 26% reduced risk of obesity later in life, according to the American Academy of Pediatrics (AAP).
But there was another interesting finding: This benefit of breast milk diminished when babies were fed pumped milk from bottles. Bottled breast milk was still better than formula, but the study suggests feeding at the breast offers the best protection against unhealthy weight gain in babies, the authors concluded.
Here’s a closer look at the results – and what they mean for mothers.
The study found a difference between direct breastfeeding and bottle feeding with pumped breast milk
“Not many studies have made the distinction between breast milk in a bottle and breast milk at the breast, so we haven’t really known there was a difference until now,” Azad said.
There are a few possible explanations for this difference, she added.
“Breast milk has all kinds of really fascinating components, like enzymes and hormones, growth factors, antibodies, even stem cells and live bacteria,” Azad said. “All of these things are normally freshly provided directly to the baby but in the case of pumping, [breast milk] may be frozen or refrigerated and some of these components might not be active anymore.”
The second possibility is that bottle feeding could affect a baby’s weight regardless of what’s inside the bottle.
But even partial breastfeeding had benefits
The authors wrote that more research is needed to learn what’s driving the observed links between different feeding practices and weight gain during infancy.
But there’s an important takeaway for mothers right now: The study found a dose-responsive benefit to breastfeeding, Azad said, meaning that any amount of breastfeeding is worthwhile.
“It’s not that you must exclusively breastfeed for six months to achieve any benefit,” she said. “Our results support this recommendation from the World Health Organisation, but they also show that if you can only do three months exclusive breastfeeding, or if you can do six months but only partially breastfeeding, it will still be beneficial. I think the message that ‘every feed counts’ is helpful for mums.”
Breastfeeding is good for mums and babies
Although breastfeeding isn’t recommended in some situations (for example, when a mum is actively using illicit drugs or has certain health issues), and while some mothers may need to use formula for a variety of reasons, a wealth of scientific evidence shows that breastfeeding benefits both babies and mothers in ways beyond healthy infant weight gain.
Breast milk has the right composition of nutrients to support a baby’s growth and contains antibodies that protect babies from some infections and health problems, according to the American College of Obstetricians and Gynecologists (ACOG). Breastfed babies also have a lower risk of sudden infant death syndrome (SIDS), the organisation adds.
In mothers, breastfeeding prompts the release of hormones that help the uterus shrink back to its normal size and can decrease post-childbirth bleeding. It may also make it easier to lose pregnancy weight and reduce the risk of breast and ovarian cancer, according to the ACOG.
But there are external factors that can hamper a mother’s ability to breastfeed. Some mums may need to pump because of their work schedules, especially in the US, which is the only developed country in the world that doesn’t require employers to offer paid leave for new mothers.
Breastfeeding’s benefits are clear. But new mothers in some parts of the world may need more support to actually reap those benefits.
“Putting all the onus on individual mothers is not how we’re going to make progress,” Azad told CNN. “It’s making this a bigger society issue. It’s about providing support, whether that’s at the family or community or policy level.”
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