Can breastfeeding help reduce obesity?
The relationship between breastfeeding and childhood obesity, as well as obesity later in life, has a bit of controversy attached to it with regard to research and scientific evidence. Before looking at that, however, let's look at two points that are entirely factual: the first concerns breastfeeding itself and the associated fact is that infant feeding decisions are entirely up to the family involved. In other words, the decision to breastfeed or use formula is a completely personal one. The second fact is that America is in the midst of what the Centers for Disease Control and Prevention consider to be an epidemic of obesity, and one that is striking young children and adolescents particularly hard.
What is also irrefutably true is that obesity has serious implications for our health, increasing the risk of many diseases and conditions, including: coronary heart disease, type 2 diabetes, certain types of cancers, high blood pressure, stroke, liver and gallbladder disease, sleep apnea and respiratory problems, osteoarthritis and gynecological problems.
Now that we've got the facts in place, back to the original idea.
A number of studies, including one carried out by the Agency for Health Care Research and Quality (AHCRQ) and endorsed by the U.S. Department of Health & Human Services, indicate that a history of breastfeeding decreases the risk of being overweight or obese in childhood and adolescence. Adolescent obesity often persists into adult life. The AHCRQ study stated that "breastfeeding plays an important role in obesity prevention and improving overall health outcomes, and therefore is vitally important to public health." The study conclusion also stated, "both duration of breastfeeding and its exclusivity should be considered when investigating the relationships between breastfeeding and obesity. The duration of breastfeeding has been shown to be inversely related to overweight -- meaning that the longer the duration of breastfeeding, the lower the odds of overweight. And although further research is needed, exclusive breastfeeding appears to have a stronger protective effect than breastfeeding combined with formula feeding."
Although this research has its proponents and a strong evidence base, a recent study published in the Journal of the American Medical Association (JAMA) takes a different perspective. The JAMA report found no changes in weight and body fat between children (at the age of 11) who were breastfed and those who weren't. Comparisons of body mass index (BMI) or measurements of waist circumference yielded, according to the JAMA study," nothing that was statistically different."
The case for breastfeeding and obesity reduction
The studies that establish a positive relationship vary somewhat but tend to focus on the following points:
- Breastfed infants are better able to control the amount of breast milk they consume, which means that they can respond to internal cues for when they are hungry and when they are full. Bottle-fed infants, on the other hand, may be encouraged to finish a bottle, which can override an infant's self-regulation of energy intake.
- Formula feeding and breastfeeding have different effects on an infant's metabolism and hormones, including insulin, which encourages the storage of fat. Formula-fed infants have higher concentrations of insulin and a longer insulin response than breastfed infants, which can result in increased weight gain and obesity. The higher protein content of formula also may increase insulin levels. In addition, studies suggest that children who were breastfed have superior concentrations of leptin in their blood. Leptin is a hormone thought to control hunger as well as body fatness.
- Breastfed babies may be more likely to try and accept new foods. Eating a wide variety of nutritious foods, including fruits and vegetables, can play a vital role in maintaining a healthy body weight.
- Breast milk includes flavors from the foods the mother eats, so a mother who eats a wide variety of healthy foods can influence her child's tastes. The taste of formula, unlike breast milk, never varies, which means a formula-fed infant does not get exposed to the variety of tastes that a breastfed baby experiences.
JAMA offers a different explanation
These results of the recent JAMA study contradict previous studies that found breastfeeding cuts the rates of overweight or obesity among children. Experts believed the practice helped to lower obesity rates because it encourages babies to eat until they're full as opposed to forcibly finishing bottles, even if they feel full. However, the JAMA researchers found that the earlier studies may have been documenting the effect of other factors on children's weight. Mothers feed babies based on how much weight the infants gain, as well as the toddlers' eating habits, so it's possible that some of the breastfed babies happened to be heavier to begin with, and that in turn prompted their mothers to feed them less. There are also a variety of cultural and educational biases that impact infant feeding. To avoid these biases the JAMA research studied babies who were randomly assigned to be breastfed or bottle-fed. The result, once the sample was truly random, is the lack of a statistical difference as described above.
At the end of the day, the JAMA results suggest that breastfeeding may not be the answer to the obesity epidemic, but the lead researcher adds that the outcomes of the JAMA study shouldn't alter existing recommendations. For proper health and nutrition, the World Health Organization advises that babies be exclusively breastfed for the first six months, and for up to two years if needed. The American Academy of Pediatrics suggests that moms breastfeed exclusively for about six months and continue breastfeeding to some extent for at least a year. The Academy goes on to say that despite the controversy related to weight and obesity, the evidence for the value of breastfeeding to children's and women's health is "scientific, solid, and continually being reaffirmed by new research."
So what does it all mean?
What we're left with regarding the role of breastfeeding in reducing obesity or the role of bottle-feeding in increasing the potential for childhood and even lifelong weight gain is no clear cut decision. It still comes down to getting all the evidence, weighing it through your own powers of evaluation, reading and listening to what the researchers, nutritionists and physicians have to say and then… making a personal decision for yourself that focuses on you and your family's best interests.
For more on childhood and adolescent obesity, see the "Guest Speaker" article in this month's newsletter.
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