Human milk is often called “liquid gold” for its incredible benefits for infants. The World Health Organization (WHO) recommends exclusive breastfeeding from the first hour after birth until the baby is 6 months old, and continuing breastfeeding along with complementary foods for up to two years. However, worldwide, fewer than half of infants under 6 months are fed in this manner. Breastmilk provides a wide range of advantages that significantly contribute to an infant’s health and development. But one of the intriguing things about breastfeeding is its impact on the microbiome.  

A baby’s diet plays a crucial role in shaping the early development of the microbiome. Breastfeeding parents’ milk contains human milk oligosaccharides (HMOs), which are complex sugars that infants can’t digest. Instead, these HMOs provide nourishment for beneficial bacteria, especially a type called Bifidobacterium, that live in the gut. Interestingly, breastfed and formula-fed infants have differences in the microbes that live in their digestive tract, particularly in their levels of Bifidobacterium.  

What’s more, studies shows formula feeding in early life is associated with specific changes in the gut microbiota, including higher levels of antibiotic resistant, harmful organisms and a lower population of beneficial bacteria such as Bifidobacterium. Babies who are partially breastfed at 3 months have a 63% higher risk of becoming overweight compared to 102% increased risk in exclusively formula-fed infants.  

Having a higher population of Bifidobacterium gives children more protection against developing allergies, asthma and obesity later in life. Research has also shown that premature infants who are breastfed have better health outcomes than those who are formula-fed and they absorb more nutrients in their first week of life. This is because their increased Bifidobacterium levels help their gut lining mature and become intact more quickly.  

Scientists are doing more research to pinpoint the direct impact of breastfeeding on the microbiome and its overall benefits to infant health. However, not everyone is comfortable with or has the ability to breastfeed, and that’s OK. If you face challenges with breastfeeding, discuss them with your health care team. This week is World Breastfeeding Week. Learn more on WHO’s website.