Antibiotics in Infants May Be a Double-Edged Sword for Immune Health

Scientists find a link between gut microbiome disruption from antibiotics and increased asthma susceptibility.

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The antibiotics that make babies better when they get an infection might be setting them up for respiratory troubles down the road.

A recent research study has found a link between early-life antibiotic use and the development of asthma and allergies in adulthood, challenging our understanding of these common medications and their long-term effects on health.

Australian Study Suggests Gut-Lung Connection

The study was conducted in Australia and published in the journal Immunity. Researchers studying mice found that a molecule produced by gut bacteria—known as indole-3-propionic acid (IPA)—is significantly depleted when antibiotics are used in early life.

“The microbiome and the immune system undergo important development steps in the first year of life, and it is during that period that antibiotic treatment can predispose an individual to allergies or asthma,” Benjamin Marsland, professor in the department of immunology and pathology at Monash University and the study’s lead author, told The Epoch Times.

“It appears from our research that IPA is particularly important early in life, and when it is not present, the developing cells in the lung can become more prone towards inflammation.”

IPA is produced through the metabolism of tryptophan and serves several important functions, including:

• Improving blood glucose levels
• Increasing insulin sensitivity
• Correcting intestinal microbial disorders
• Inhibiting the penetration of toxins
• Modulating the immune system’s response

The study marks the first time that IPA has been associated with protection against the future development of asthma, Marsland said.

Asthma is defined as a long-term lung condition caused by the narrowing of the airways when inflamed. It is the most common chronic disease among children.

Airway inflammation is a key component of allergic reactions. When people with allergies come into contact with an allergen—such as dust—their immune system overreacts. This overreaction triggers the release of chemicals, including histamine, that cause inflammation in the airways.

In the study, when mice were given antibiotics in their first year of life, they became more susceptible to inflammation of the airways from house dust mites. This susceptibility lasted into adulthood—even after their IPA and gut microbiome levels returned to normal, the study found.

However, when the mice in their first year had their diet supplemented with the IPA molecule, they were effectively cured of developing the house dust mite-induced airway inflammation, or asthma, in adulthood.

Antibiotic use has been similarly shown to lower IPA levels in humans, Marsland said, suggesting that the Australian study’s findings may have implications for human health.

“It highlights the possibility of IPA being used as an adjunct therapy with antibiotics in early life with a view to offsetting the negative impact of antibiotics and protecting the developing cells in the lung,” he said.

Antibiotic treatment is a known risk factor for later asthma in humans, and antibiotics can kill not only “bad” bacteria, but also some of the “good” ones that promote health, Marsland said.

Caution Needed: Study

A separate longitudinal study, published in the International Journal of ObGyn and Health Sciences, involving 300 children ages 1 to 5, identified a concerning trend.

Children who received antibiotics showed a “significant” reduction in the abundance and diversity of gut microbiota, and subsequently experienced a higher incidence of respiratory and gastrointestinal infections compared to those with lower or no exposure to antibiotics.

The researchers discovered that antibiotic use disrupted the gut microbiome and immune regulation, making children more susceptible to pathogenic invasions. This vulnerability created a cycle of recurrent infections and repeated antibiotic use.

Interestingly, older children showed a more resilient response to antibiotic exposure.

“Although there were still notable disruptions in their microbiota and immune parameters, the effects were less severe and the recovery period was shorter compared to younger children,” the researchers wrote. “This suggests that the immune system’s increasing maturity provides some degree of buffering against the adverse effects of antibiotics.”

“Given their heightened vulnerability to microbiome disruption and immune dysregulation, antibiotic use in children aged 1–2 years should be especially cautious.”

The studies come as the Australian Commission on Safety and Quality in Health Care (ACSQHC) published a report in August stating that there is “little to no benefit” when taking antibiotics for common infections.

Antibiotics are medicines that are used to treat diseases and infections caused by bacteria, and should only be used if they are needed to treat a bacterial infection, according to the commission.

The ACSQHC wrote that while antimicrobials (which include antibiotics, antivirals, antifungals, and antiparasitic agents) are an integral component in health care, overuse of antibiotics has caused antimicrobial resistance to develop, thereby impacting important treatments, such as chemotherapy for cancer, diabetes management, organ transplantation, and major surgical procedures.