The Breast Is Best: More Then 700 Species of Bacteria in Breast Milk
Spanish researchers have identified more than 700 species of bacteria living in breast milk that’s produced in the first few days of baby’s life. The discovery surprised researchers, who did not expect to find such a wide diversity of bacteria thriving in human breast milk. Scientists believe bacteria from breast milk help colonize a baby’s gut, and they suspect that some of these bacteria play an important, and beneficial, role in baby’s developing immune system.
Investigators used a sophisticated DNA sequencing technique to determine the identities of different bacteria species living in colostrum. Colostrum, or “first milk” is especially rich in antibodies, enzymes and protein, among other nutrients. It’s the first milk most babies receive, and it’s usually followed by ordinary breast milk after the first few days of breastfeeding.
The makeup of bacteria in breast milk also changes over time, researchers found. While it’s still not clear what role the many types of bacteria may play in baby’s health, this diversity of microbes appears to be healthy and natural. Investigators also found less bacterial diversity in the milk of obese and overweight mothers. Similarly, women who underwent unplanned caesarean section deliveries also produced milk with less bacterial diversity. These findings suggest that a greater diversity of bacteria in breast milk is both natural and beneficial.
Cabrera-Rubio R, Collado MC, Laitinen K, Salminen S, Isolauri E, Mira A. The human milk microbiome changes over lactation and is shaped by maternal weight and mode of delivery. Am J Clin Nutr. 2012 Sep;96(3):544-51. doi: 10.3945/ajcn.112.037382. Epub 2012 Jul 25.