Breast milk helps babies fight infection and stay healthy

Every newborn begins life with a simple act – feeding. Yet, inside every drop of breast milk, something extraordinary happens. It carries instructions that train a baby’s immune system, shape metabolism, and build protection that lasts far beyond infancy.

Researchers from the Murdoch Children’s Research Institute (MCRI) and the Baker Heart and Diabetes Institute have now uncovered how this early nourishment protects babies from infections and inflammation.

Their findings explain why babies breastfed for at least six months grow stronger and stay healthier.

More than nourishment

The study, published in BMC Medicine, found that breastfed infants show fewer signs of chronic inflammation.

Babies who received breast milk had lower levels of glycoprotein acetyls, a molecule that signals long-term inflammation. This suggests breastfeeding changes the body’s chemistry in ways that support lasting health.

How inflammation starts

Inflammation is the body’s natural defense. It helps heal wounds and fight infections. But when inflammation lingers, it can become harmful. Chronic inflammation in adults leads to diabetes, heart disease, and even asthma.

This study showed that breastfeeding helps control inflammation early, preventing it from turning into a long-term problem.

Protective fats in breast milk

“Plasmalogens are only found in breastmilk and are generally absent in formula milk, so a better understanding of how plasmalogens and other lipids unique to breastmilk protect against chronic inflammation will help pave the way for new treatments for infants who don’t receive breastmilk,” explained MCRI’s Dr. Toby Mansell.

These lipids, called plasmalogens, work like tiny shields. They protect cells from stress and help the immune system stay calm. Babies who had more of these lipids in their blood showed stronger defenses against infection.

Tracking health from birth

To understand this better, scientists studied 889 infants from the Barwon Infant Study in Victoria, Australia. They analyzed blood samples taken at six and twelve months of age and looked at more than 800 types of lipids and 250 metabolic markers.

The results were striking. Babies who were breastfed had more healthy fats like omega-3s and beneficial HDL cholesterol. Their bodies processed fats differently, showing a clear metabolic signature of better health. Formula-fed babies, in contrast, showed higher levels of lipids linked to inflammation.

Breast milk boosts immunity

Dr. Satvika Burugupalli from the Baker Institute described the central role of breast milk in immune protection. “Breast milk performs a central role in supporting a newborn’s immune system,” she said. “It’s loaded with essential nutrients, including lipids, as well as antibodies and white blood cells.”

Her words reflect what the data shows – breast milk doesn’t just feed a child, it trains the immune system. Infants who were breastfed had fewer colds, respiratory issues, and gut infections in their first year. Their blood chemistry showed lower markers of inflammation, even months later.

Chemistry of growth

Breast milk also affects how babies process energy. It changes the balance between good and bad fats, increases protective ether lipids, and reduces lipoproteins that cause inflammation. These shifts happen fast – within months – and lay the foundation for a healthier metabolism later in life.

Scientists noticed something else too. Lipids and inflammation influenced each other. Healthy lipids reduced inflammation, and lower inflammation helped maintain healthy lipids. It’s a cycle that keeps the body balanced from the very beginning.

Plasmalogens: Tiny defenders

Among all the molecules studied, plasmalogens stood out. These compounds had a powerful link to reduced inflammation. Babies with higher plasmalogen levels had fewer infections and lower inflammation overall.

Plasmalogens act as antioxidants. They protect immune cells from oxidative stress and might even prevent a kind of cell death called ferroptosis. This keeps the body from overreacting to everyday microbes, building calm, steady immunity.

Beyond the first year

Breastfeeding also improves how the body uses energy. Infants who received breast milk could easily switch between burning fats and carbohydrates. This flexibility may lower the chances of obesity, heart disease, or diabetes later in life.

Even partial breastfeeding showed benefits. Every bit of breast milk exposure contributed to better health outcomes. The findings support the World Health Organization’s advice to continue breastfeeding for at least six months.

Lipids as natural medicine

The study’s findings highlight something remarkable – nature built a perfect formula for early survival. The lipids in breast milk don’t just feed cells; they guide them.

They tell immune cells when to fight and when to rest. This might explain why breastfed children tend to have fewer allergies, asthma, and inflammatory conditions.

These discoveries could one day change how formula is designed. Understanding how these lipids work might help create alternatives that mimic the real thing, giving every child a stronger start.

The impact of breast milk

“This study has identified key biological pathways for how breastfeeding improves immune health and reduces inflammation that can lead to many childhood conditions, such as allergies and asthma, and the risk of adult cardiovascular disease and diabetes,” Dr. Burugupalli noted.

Every drop of breast milk carries more than nutrients. It carries biological wisdom passed down through generations. Science is now learning to read that language. For babies who can’t be breastfed, this understanding could lead to formulas that do more than feed – they could heal.

The research involved scientists from the University of Melbourne, Deakin University, Barwon Health, Northwestern University, and the Florey Institute of Neuroscience and Mental Health. Together, they decoded how milk communicates with the body – one molecule at a time.

The study is published in the journal BMC Medicine.

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