by Jeanmarie Burigo Connor
March 05, 2009

“A pair of substantial mammary glands have the advantage over the two hemispheres of the most learned professor’s brain in the art of compounding a nutritive fluid for infants.”

This statement by Chief Justice Oliver Wendell Holmes in the late 19th century still holds true today. Breastfeeding offers countless advantages. Breast milk is composed primarily of whey proteins, which consist of secretory IgA antibodies, lactoferrin, lysozyme, and a plethora of other nutrients that are involved in host defense. Whey proteins are digested more easily by infants, promote gastric emptying, and also provide local gastrointestinal immunity against organisms entering the body via this route. Studies suggest that children who are breastfed have a decreased incidence of gastrointestinal infections, including necrotizing enterocolitis, as well as respiratory tract infections and otitis media. Breast milk also contains arachidonic acid (AA) and docohexaenoic acid (DHA) that are important in the formation of neuronal and retinal tissues in infants. In addition to all these important advantages, breast milk has recently been identified as having a protective effect on infants against sudden infant death syndrome (SIDS).

What is SIDS?
As the name implies, SIDS is the sudden and unexplained death of an infant less than one year of age. Most SIDS deaths are associated with sleep which is why the American Academy of Pediatrics recommended in 1992 and reaffirmed in 2009 that all infants be placed on their backs to sleep. Since that recommendation, the frequency of prone (face down) sleeping has decreased from 70 percent to 20 percent among United States (U.S.) infants and the SIDS rate has decreased by over 40 percent during that time period. Nevertheless, SIDS remains the leading cause of infant death beyond the neonatal period. Why? Although the answer is unknown, there are several other risk factors that may be involved. These factors include, but are not limited to tobacco exposure in the home, maternal smoking during pregnancy, excess bedding and clothing on the infant, and “co-sleeping” practices in which an infant shares a sleep surface with an adult.

Although an association between breastfeeding and SIDS has long been suggested, a recent study in the journal Pediatrics revealed that breastfeeding reduced the risk of sudden infant death syndrome by nearly 50 percent at all ages throughout infancy.

Research
Conducted in Germany from 1998 to 2001, the study included 333 infants who died from SIDS and 998 age-matched “control” subjects who were not affected by SIDS. Of the infants who died from SIDS, 59 percent were between the ages of 2 and 5 months demonstrating that the incidence is greatest in children less than 6 months of age.

Parents were asked to describe their infant’s feeding pattern as “breastfeeding only,” “partial breastfeeding” (defined as any formula or solids given in addition to breast milk), and “no breastfeeding.”  The infant’s feeding regimen was examined at 2 weeks of age, 1 month of age, and in the last month of life or in the month prior to the interview for the “control group” of infants. Researchers controlled for variables that are thought to contribute to an infant’s SIDS risk including maternal smoking in pregnancy, maternal family status, maternal age at delivery, socioeconomic status of the family, previous live births, birth weight of the infant, co-sleeping practices, pillow in the infant’s bed, temperature of the child’s room, pacifier use, and sleep position.

Results
Study results revealed that 83 percent of the controls and 53 percent of the SIDS infants were breastfed at 2 weeks of age. The corresponding percentages at one month of age were 72 percent and 40 percent. In the last month of life or for those in the control group, at one month prior to the interview, 40 percent of infants in the control group were breastfed compared to only 10 percent of the SIDS infants. Partial breastfeeding was associated with a reduced risk of SIDS as well. However, this result was not statistically significant which suggests that this finding could have been due to chance.

Recommendations
Breastfeeding reduced the risk of SIDS by at least 50 percent at all ages. Fifty-nine percent of the infants who died were 2 to 5 months of age; 73 percent of those who died were less than 6 months of age. These results suggest that the benefit of breastfeeding, especially exclusive breastfeeding for infants is significant at an early age and that every effort should be made to encourage breastfeeding at least until the infant reaches 6 months of age when the risk of SIDS becomes substantially lower.

It is not fully understood why breastfeeding decreases the risk of SIDS. Some data suggest that the immunologic components in breast milk prevent infection and inhibit the release of pro-inflammatory cytokines, proteins that cause respiratory and cardiac dysfunction.

We may not have all the answers, but we can be sure of one thing: breast milk is the best nutrition for babies, and this study highlights one more reason why breast milk is the way to go.