Obesity is reaching epidemic proportions in the United States, with 31 percent of adults and around 15 percent of teens now obese by medical definition.
Obesity is a serious health concern, being linked with problems such as diabetes and heart disease, and with a shorter life expectancy.
This obesity epidemic has occurred along with low levels of breastfeeding, but links between the two have been hard to study. This is mainly because mothers who breastfeed tend to have higher education levels and higher incomes, both linked to less weight problems in their offspring.
Dr. Matthew Gilman surveyed over 5,000 children aged between 9 and 14 and was able to compare siblings who had been breastfed for different durations.
He found that, even within a single family, children who were breastfed for a longer period were less likely to become obese in the teen years, and that this advantage increased with the duration of nursing.
Gilman and colleagues estimate that, for every 4 months of extra breastfeeding, the risk of teen obesity was reduced by 6 percent. For example, an infant breastfed to age 1 has a 24 percent lower chance of teen weight problems than a baby weaned soon after birth.
Dr. Gilman suggests that breastfeeding may have lasting positive effects on body metabolism and may also allow children to self-regulate their intake: a skill that may help them to keep a normal weight life-long.
Guest Commentary by Sarah J. Buckley MD:
Breastfeeding rates are rising in the United States, but few infants are nursed beyond the early months. This trend is unusual: most of our foremothers nursed their babies for at least a year, and in many places, breastfeeding to age 2 or beyond is still the norm.
With our increasing understanding of the many benefits of nursing, many are now recommending a longer duration of breastfeeding. Both the American Academy of Pediatrics and the American Academy of Family Physicians advocate at least 12 months of nursing, and the World Health Organization recommends at least two years for optimal growth, development, and health.
Babies who are breastfed through the first year of life have fewer illnesses, both minor and major, and a lower chance of death, which extends to at least 3 years of age.
Breastfeeding gives young children protection from deaths due to SIDS and injuries, as well as infections. The American Academy of Family Physicians states, "If the child is younger than two years of age, the child is at increased risk of illness if weaned."
The benefits of breastfeeding increase with duration, and the disease-protective effects actually increase as weaning approaches. Some have called this increased concentration of antibodies, as breastfeeding declines, the "parting gift" to the baby, ensuring on-going good health and strong immunity.
Breastfeeding into the second year also gives a strong benefit in terms of nutrition. Research from Kenya, where the nursing mothers had poor diets, has estimated that breastmilk can supply up to one-third of a toddler's daily energy needs, as well as two-thirds of fat requirements, 58 percent of vitamin A requirements, and almost a third of calcium needs.
A U.S. study shows that children who are breastfed through the first year have a better food intake, and need less persuasion to eat well, in the second year.
All references for this information are available in Sarah's essay "Extended Breastfeeding: the gift of a lifetime" in Gentle Birth, Gentle Mothering: The wisdom and science of gentle choices in pregnancy, birth, and parenting, which can be found at her Web site. More information also available at ProMoM and the La Leche League.
Sarah J. Buckley, MD, is a writer on pregnancy, birth, and parenting.