A new research review from The University of Texas Health Science Center at Houston (UTHealth) School of Public Health adds to the growing body of evidence showing that breastfeeding protects against childhood obesity.
[Photo: (left to right) Ms. Katie Newsome, Ms. Tasnuva Rashid, Ms. Helena Vonville and Dr. Shreela Sharma. ]
The study, which appears in the journal, Current Nutrition Reports, could help guide breastfeeding health promotion efforts.
UTHealth School of Public Health researchers systematically mapped 29 review articles looking at the relationship between breastfeeding and obesity. They found that breastfeeding was associated with a lower risk of childhood obesity, and children who were breastfed the longest had the lowest rates of obesity.
“The results show that breastfeeding does protect against obesity risk in the child, and the duration of breastfeeding also matters in reducing this obesity risk,” says senior author, Dr. Shreela Sharma, an associate professor in the department of epidemiology, human genetics and environmental sciences and assistant director of the school’s dietetic internship program.
Study co-authors include Ms. Katie Newsome, a second-year MPH student who is also in the school’s Dietetic Internship Program; Ms. Tasnuva Rashid, a fourth-year PhD student in the department of epidemiology, human genetics and environmental sciences; and Ms. Helena Vonville, director of library services for UTHealth School of Public Health.
The health benefits of breastfeeding have been well established in research literature. Breastfeeding has been shown to protect against diarrhea, respiratory infections, necrotizing enterocolitis, ear infections and diabetes, as well as decrease the risk for childhood obesity.
It is unknown how exactly breastfeeding protects against obesity in the child, but many factors could play a role. Breastmilk is easily digestible and nutritious — containing the perfect balance of nutrients and immunological factors specific to human babies. Babies who breastfeed are better able to regulate their food intake, and are less likely to overeat. And breastfeeding spurs the release of hormones that help regulate appetite and metabolism in the child.
The World Health Organization and American Academy of Pediatrics recommend that infants exclusively breastfeed for six months and receive complementary foods in addition to breastmilk for one to two years. Yet, breastfeeding rates continue to decline worldwide, while child obesity rates remain high, say the study authors. In the United States, an estimated 18.8 percent of infants were exclusively breastfed in 2011.
The researchers hope their study will help boost those rates, by informing the design of evidence-based breastfeeding initiatives.
“There is a plethora of knowledge and information on breastfeeding and obesity, but the current information had not yet been linked in a manner that would prove useful to multiple populations,” says Ms. Newsome. “Mapping gave us the opportunity to organize known research in a manner that could be utilized for health promotion efforts.”
A mapping review visually links information in published research reviews to expose gaps in knowledge and practice. The researchers compared and contrasted studies on breastfeeding and obesity published between 1946 and 2016, and scored them from one to 10 according to the validity of their study design, using the AMSTAR tool, an instrument used in assessing the methodological quality of systematic reviews. Sharma says the process allowed them to rank the reviews in order of their quality.
Looking at the study’s charts and tables, readers can easily see how the included studies are ranked, and the geographical areas covered.
“The mapping not only showed us what information was there, but what wasn’t there,” Dr. Sharma says. The study found that the duration of breastfeeding and exclusive breastfeeding were key predictors of obesity in young children, and should be key messaging targets for health promotion efforts. However, information on whether the benefits of breastfeeding continue into adulthood is lacking, as well as data on breastfeeding and obesity risk in other subgroups such as African-American and Hispanic children.
Future research focusing on more geographically and ethnically diverse populations, using experimental designs and longer duration of follow-up in the child, is warranted, say the authors.
But for now, the study creates a baseline for research on breastfeeding and obesity that will help prevent the repetition of similar studies, as well as identify research gaps and populations to target with breastfeeding initiatives, says Ms. Rashid. The study results can also be applied to current breastfeeding health promotion efforts.
“Health care professionals can use these results in their day-to-day clinical practice so as to encourage longer duration of breastfeeding, and also incorporate them into targeted nutritional interventions,” she says.