5 latest discoveries regarding the microbiome in breast milk

In the last 2 decades there was an accumulation of  scientific evidence regarding the crucial role of microbiome, or as a simple term, gut flora” for our general health. Babies microbiome is built after birth. Disturbances in the establishment of the indigenous intestinal microbiome in early life have been linked to the risk of immune-mediated and inflammatory conditions such as atopic disorders, inflammatory bowel disease, type 1 diabetes, asthma and obesity later in life. 

It is known that breast milk modulates immune and metabolic programming. But lately scientists have identified breast milk as a major contributor to the infant microbiome. Here is what you need to know about it:

  1. 700 types of bacteria in one ounce of breast milk. Breast milk contains a lot of ‘good’ bacteria when it comes directly from the mother’s breast — ‘good’ bacteria content is decreased in the same milk when it is pumped and delivered later by bottle. Nevertheless, pumped milk still carries most other riches of breast milk and even a smaller number of bacteria is better than none (formula doesn’t give your baby any of the much-needed microbiome components). Studies suggest that a single ounce of breast milk can contain over 700 species of ‘good’ bacteria that contribute to the development of the infant's gut microbiome. It’s hypothesized that specialized immune cells, called dendritic cells, transport bacteria from the mother’s gut to the mammary glands, where they are then passed on to your baby in breast milk. 
  2. Breastfeeding directly from the breast increases microbiome diversity. Diverse microbiome is considered to be a marker of good This comes from the consumption of the breastmilk itself as well as from the exchange of microbes from the surface of the mother’s skin during the act of breastfeeding. Multiple studies have consistently demonstrated that exclusively breastfed infants differ from and have more healthful microbiome profiles compared to their non-exclusively breastfed counterparts.
  3. Microbial content varies every day. Over 150 sugars (oligosaccharides) feed your baby’s intestinal microbes to keep healthy digestive bacteria flourishing. Bacteria from your body transfer through your milk to help your baby establish his or her own gut flora and immune system. The precise microbial makeup changes every day and season.
  4. Breast milk feeds ‘good’ bacteria in your baby’s digestive system. New scientific evidence show that the gut microbiome is first seeded in the womb. The microbiome, however, is anything but stable. It adapts to a variety of environmental factors, including diet. Breast milk has a unique influence on your baby’s One of the most dominant nutrient-family in human breast milk, are human milk oligosaccharides (HMOs). These oligosaccharides are the sugars in breast milk that are a food source for bacteria, but can't be digested by babies. Amazingly, strains of ‘good’ bacteria, are happy consumers of HMOs while pathogenic strains - are either poorly adapted to consume HMOs or even unable to metabolize them altogether. This is a positive feedback loop that helps the baby’s immune system- the more ‘good’ bacteria that establish in the infant gut, the more difficult it is for pathogenic strains to compete for limited space and resources.
  5. Breast milk contains decoys to fool bad bacteria. Breast milk protects your baby against different pathogens in many ways, but  one of the astonishing ways was discovered recently. HMOs (human milk oligosaccharides) trap ‘bad’ bacteria and prevent it from growing in your baby’s gut. For a pathogen to invade your baby’s gut cells, it needs to attach to the cells. in order to do so, it must first attach to receptors on the surface of the epithelial cells that line the gut, like using a key in a locked door. HMOs actually serve as a decoy receptor, as they possess the identical receptors that the pathogen uses to invade cells. So, when bacteria attaches to the HMOs instead of the baby gut cells, these harmless sugar-bacteria complexes are then flushed from the intestine. 



The American Academy of Pediatrics currently recommends that babies will be exclusively breastfed for at least 6 months and continue to do so, as soft and solid foods are introduced, for 1 year or longer  because many of breast milk health benefits are associated with extended cumulative periods of exclusive breastfeeding. Only 13% of the population currently meets the 6-month recommendation, but the numbers are consistently rising…