Breast and human milk microbiome

Breastfeeding is a natural instinct of motherhood and breast milk is considered as the gold standard for providing young infants with the nutrition they need for healthy growth and development. It has been long recognized as important course associated with the mother and child care.  Breastfeeding is known to reduce the incidence of diabetes and breast and ovarian cancer in mothers and also the incidence of mortality due to infections in children. Milk is rich in nutrients, bioactive molecules, few maternal cells, and extracellular vesicles. It also contains a unique mélange of hormones, antibodies, and bacteria that is a presumably evolved mixture to meet most of the infant dietary needs. Milk and breast tissue has its own unique microbiome which is a result of adaptation to the fatty acid environment. Although previously considered sterile, breast milk is now known to contain a complex community of bacteria that helps establish the infant gut. If this practice is disturbed, the infant may be a dysbiosis in gut microbiota, causing predisposition to chronic diseases such as allergy, asthma, and obesity. 

  • It has been estimated that an infant consumes approximately 750 mL of milk per day and ingests between ten to a hundred thousand bacteria daily.
  • The breast has its own microbiome and breastfed infants are always exposed to bacteria present on the skin and in the breast milk of their mother. Nonetheless, bottle-fed infants are exposed to only a few selected microbes.
  • Exclusive breast feeding increases the diversity of ‘Bifidobacterium’ [bifid means separated into two equal parts; like Y-shaped bacteria] in the gut of infants.  It is a first bacterium to colonize infant’s gut. Bifidobacterium has positive health benefits on the infants as these bacteria can consume special sugars found in breast milk, that babies cannot otherwise digest.
  • Bottle-fed infants are more frequently colonized digestive track with bad or pathogenic germs than the breastfed children. By contrast, in breast-fed children, have more useful Bifidobacterium in their gut.
  • Colicky babies have inflammation and bacteria that lead to severe abdominal pain and such babies cry more. Whereas babies without colic had no inflammation and have more varieties of good bacteria in their gut.
  • Bacterium Lactobacillus reuteri found in breast milk is known to decreases the force of muscle contractions in the gut. When colicky babies are given this bacterium, they do not experience as much painful cramping and cry less.
  • On the contrary, breastfeeding may a major issue if the mother is exposed to many antibiotics and carry antibiotic-resistant bacteria as her microbiome.  Infants acquire this antibiotic-resistant microbiota from their mother’s gut and breast milk microbiota.

Gut Microbiome

Diet and lifestyle are crucial factors that control the vulnerability of women to metabolic diseases such as obesity, diabetes, and high blood pressure. The gut harbors a large selective gathering of microorganisms and nutrition influences the composition and function of gut microbiota from birth to adulthood. Gut microbiome display many important activities associated with utilization of non-digestible carbohydrates and host-derived mucus, deconjugation of bile, biosynthesis of vitamins like K and B group. Based on this collective metabolic potential, the gut microbiota can be viewed as a separate ‘microbial organ’. Gut microbiome makes the internal lining of gut robust so that harmful bacteria can not cross the barrier. The normal gut microbiome augments the immune system and disease-fighting competence of an individual.

  • At young age, there is an existence of a large variety in gut microbiome in both men and women. However, young women display greater biodiversity than young men and this may be attributed to the sex hormones.
  • Women are known to suffer more from autoimmune diseases and this sex-biased autoimmunity depends on the gut microbiome and female-specific sex hormones. One such autoimmune disease is Chronic Fatigue Syndrome, which has demonstrable sex-specific interactions with the gut microbiome. Changes in the healthy state of microbiome lead to increased symptoms and the severity of this syndrome in women.
  • Sex-specific alteration of gut microbiota plays a vital role in the development or presentation of autism spectrum disorder symptoms due to alteration in gut-skin-brain axis interaction with the microbiome.
  • Obesity is a multifactorial disorder that involves genetic susceptibility and environmental factors, such as lifestyle and inappropriate diet. Now, the gut microbiome has been suggested as a driving force in the causing different metabolic disorders including obesity.
  • Consumption of health-promoting bacteria termed as ‘Probiotics’ reduces the fat cell size in different adipose depots and is attributed to increasing in lipolysis, fecal excretion of sterols and bile, and decrease in absorption of triglycerides, phospholipids, and cholesterol.

    Thus microbiome of a woman is unique and adds to special attributes, behaviors, and roles to femininity. A woman is always delighted in her feminineness.  Retaining the undisturbed microbiome is a key to stay healthy and active. Several factors manipulate the microbiome in both positive and negative ways. Food habits, climate changes, anxiety, poor health, and certain medications can affect the microbiota. Unnecessary consumption of antacids which decrease acid in the stomach and may allow the bad bugs to thrive in the stomach and make their way into the colon causes dysbiosis. Animal meat fats, refined sugars, and flours help unwanted bacteria to flourish and cause dysbiosis. The complexity of dysbiosis increases with the consumption of meat and dairy products obtained from animals treated with antibiotics, steroids, growth hormones, and other drugs. However, fresh vegetables, whole grains, and fermented foods like idli, curds and butter milk has good bacteria that flourish good ones. So to remain in good physical shape, maintain the state of healthy microbiome composition.

Dr. Milind S. Patole & Nitin Bayal

Dr. Milind Patole is Scientist ‘G’ at the National Centre for Cell Science, Pune. Nitin Bayal is Ph.D. scholar at National Centre for Cell Science, Pune


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