Understanding Breastfeeding at the Cellular Level

Breastfeeding provides many health benefits to both mother and child. These benefits occur in a dose-response relationship. That is, the longer a child is breastfed, the lower his or her risk for a variety of illnesses including severe diarrhea, pneumonia, asthma, ear infections. While most mothers hope to breast-feed according to current recommen-dations (6 months of exclusive breast-feeding and breast-feeding combined with solid foods until 12 months or longer), the majority do not achieve their goals. Health care providers and lactation consultants advise mothers that extra breastfeeding or pumping will increase their milk pro-duction and prolong lactation. Neither they nor the scientific com-munity really understand why this does not always work.

Dr. Darryl Hadsell, a research scientist at the USDA/ARS Children’s Nutrition Research Center, is working to understand how milk production is regulated at the cellular level using mice mammary cells. Ultimately, this research will provide medical professionals with more information on which to base advice to breastfeeding mothers who need to increase their milk production or reverse an unexplained decreased in milk volume.

Changes occur when mouse lactation is “rescued”-—that is when lactation is extended past the time when those cells tend to stop producing milk. In mice, as in people, lactation can be extended or “rescued” by continuing to remove milk from the gland after the baby is weaned. Even under these conditions, there is an eventual decrease in milk production—and Dr. Hadsell has shown that this decrease is associated with a corres-ponding decrease in the number of milk producing cells in the mammary gland. Some of the cells just slowly die—even though the milk is still being removed.

Whatever the control mechanisms, Dr. Hadsell is particularly struck by the fact that the cellular processes of early rapid growth, aging, and death that occur slowly throughout the body seem to be occurring in fast forward during each cycle of early and prolonged lactation. This makes it even more important to understand the mechan-isms involved and suggests that these results may have implications not just for lactating women, but for other aspects of human health such as aging.

More about Dr. Hadsell’s research can be found in the April 2006 issue of Experimental Gerontology or on the CNRC website www.kidsnutrition.org/faculty/hadsell.htm.