By Megan Rauscher
New York - Breast-feeding in infancy appears to be associated with a reduced risk of type 2 diabetes later in life, according to a quantitative analysis of published evidence conducted by investigators in the United Kingdom.
"Whether this effect is attributed to a difference in the content of breast milk compared to formula milk, or whether the family environment and nurture of infants breast-fed differs from those formula fed remains to be established," Dr. Christopher Owen who led the study told Reuters Health.
In either case, breast-milk is "the food of choice in infancy, based on numerous short- and long-term health benefits," added Owen, of St George's, University of London.
Because evidence from individual studies that examined the relationship between breast-feeding and the risk of type 2 diabetes has been inconsistent, Owen's team conducted a systematic review and pooled analysis of relevant studies published in the medical literature on the topic.
In seven studies involving 76 744 subjects, those who were breast-fed as infants had a 39 percent lower risk of developing type 2 diabetes in adulthood. The findings of these seven studies were "broadly consistent, despite widely differing nature of the populations," the authors note in the American Journal of Clinical Nutrition.
In six studies involving 4 800 subjects, levels of insulin - the body's key blood sugar-regulating hormone - were marginally lower in breast-fed non-diabetic children and adults compared with formula-fed non-diabetic children and adults.
In these studies, fasting blood sugar concentrations were no different in breast-fed and formula fed children and adults. However, in infancy, breast-feeding was consistently related to lower concentrations of blood sugar and insulin than was formula feeding. Chronically high levels of insulin raise the risk of heart disease and exacerbate the effect of diabetes.
"On the basis of the published evidence, breast-feeding may provide a degree of long-term protection against the development of type 2 diabetes, which could be of public health importance," Owen and colleagues conclude.
SOURCE: American Journal of Clinical Nutrition, November 2006.