Why Mom’s Milk Makes Baby’s Tummy Super Strong!

The moment a baby is born, friendly bacteria, also known as probiotics, start colonizing their intestinal tract. These bacteria play a crucial role in promoting the digestion of nutrients and development of the immune system. But did you know that you can give your baby a head start in building up these good bugs? One word: breastfeeding.

Research carried out by collaborators from the University of Illinois, Texas A&M University, Miami University, and the University of Arkansas has shown that breast milk contributes to the growth of microbes that boost an infant’s developing immune system. Babies fed exclusively on breast milk have more diverse bacterial colonization than those who are formula-fed. Additionally, the researchers found a connection between the expression of genes in these bacteria and the infant’s immune system genes.

According to scientist Sharon Donovan of the University of Illinois, this research helps us “define exactly why breast is best.” Here are some important aspects related to breastfeeding and the development of an infant’s immune system.

The Unique Properties of Breast Milk

Breast milk is a highly complex and dynamic substance that evolves along with the growing and changing needs of the baby. It contains various classes of proteins, lipids, carbohydrates, vitamins, minerals, and bioactive components, like immune molecules, hormones, and growth factors. These components interact with each other and the baby’s growing body in many ways, helping the infant fight off potential diseases.

One of the essential components of breast milk is human milk oligosaccharides (HMOs) which are indigestible sugars. They are the third most abundant solid component in breast milk, playing vital roles in shaping the infant’s gut microbiota and immune responses. HMOs act as prebiotics, stimulating the growth of specific beneficial bacteria such as Bifidobacteria and Lactobacilli, which support the infant’s immune system by creating an acidic environment that kills off harmful bacteria.

Meanwhile, another component, the long-chain polyunsaturated fatty acids (LCPUFAs) found in breast milk, affect the infant’s immune cell membrane composition and function, allowing appropriate immune responses to external stimuli. Additionally, breastfeeding mothers transfer various human milk cells, including leukocytes, to their babies, aiding in immune system development and disease defense.

Formula Vs. Breast Milk

While infant formulas have been designed to mimic the composition of breast milk, they are incapable of replicating its immunological properties and complexity. Formula-fed infants miss out on the immune protection provided by milk leukocytes, one of the essential components transferred from mother to baby during breastfeeding.

Moreover, formula-fed infants lack the amount and diversity of good gut bacteria, making them more susceptible to infections and chronic health conditions like obesity and type 1 diabetes.

The Long-lasting Effects of Breastfeeding

Breastfeeding not only impacts the infant’s early life but also has long-lasting effects on the child’s health until adulthood. Studies show that exclusive breastfeeding for the first six months of life followed by complementary feeding decreases the risks of infection, obesity, type 1 and 2 diabetes, and inflammatory bowel diseases.

Due to the stimulation and maturation of the immune system during breastfeeding, former breastfed individuals continue to show lower incidences of various autoimmune diseases. Moreover, the positive effects on gut microbiota and immune system stretch into adolescence, with studies showing a decrease in allergy, asthma, and atopy risk.


Breast milk, with its unique composition, continually and adaptively supports the infant’s developing immune system and intestinal microbiota. Not only does breastfeeding provide lifelong health benefits, but it also creates an unparalleled bond between mother and baby – fostering physical and emotional comfort.

So, next time someone asks if breast is best, you know the answer: Yes, because it impacts the baby’s health in unparalleled ways, setting the foundation for a lifetime of health benefits and improved immune system function.