Antibiotics are a sometimes necessary evil, but they can upset the bodys delicate bacterial balance.

For the gut in particular which is home to trillions of bacteria that play a crucial role in our physical and mental health antibiotics can cause serious damage. The healthy bacteria inhabiting the digestive tract are critical for maintaining the health of the digestive system, brain and immune systemin particular, along with numerous other systems in the body. One single course of antibiotics can indiscriminately kill off hundreds of important strains of healthy bacteria alongside the bad bacteria it aims to target.

Now, a Monash University study involving mice, published in the April issue of the Journal of Leukocyte Biology, finds that childhood antibiotic use impedes the normal growth and development of gut bacteria. This, in turn, affects the function of the immune system around 70 percent of which is contained in the gut.

This can lead to inflammatory diseases like multiple sclerosis, inflammatory bowel syndrome and asthma in adulthood, the research found.

The Gut-Immune System Connection

For the study, the researchers treated female mice with broad spectrum antibiotics during pregnancy and also treated their pups with the same drugs during their first three weeks of life. A second group of pregnant mice and pups their remained untreated to act as a control.

The pups treated with antibiotics had reduced levels of gut bacteria, as was expected. When the pups were eight weeks old, the researchers examined a specific type of immune cells (known as CD4 T cells) from both the treated and untreated groups to examine their ability to induce an inflammatory bowel disease in other mice.The scientists found that immune cells from the antibiotic-treated mice induced a significantly more severe and rapidly forming disease than those from the untreated mice.

Our intestinal bacteria are now understood to have a major role in shaping immune health and disease, but the details for this process remain poorly understood, said John Wherry, Ph.D., deputy editor of the journal in which the study was published,in a press release.These new studies provide an important clue as to how the early signals from our gut bacteria shape key immune cells and how these neonatal events can shape disease potential later in life.

CD4 T cells are known to play a critical role in the inflammatory response. Dysfunction in these cells is involved in the over-active immune response that eventually leads to the developmentof chronic inflammatory conditions like Crohns, lupus, multiple sclerosis and other autoimmune diseases.Previous studies have shown that the use of certain antibioticscan trigger autoimmunity, but now we have a better idea of how this happens.

New hope for preventing and treating autoimmune disease

The findings add growing weight to the idea that targeting gut bacteria may be an important way to treat inflammatory diseases.

The good news is that certain lifestyle changes like adopting a gut-healthy diet, managing stress levels and exercising regularly can make a real difference for gut, and therefore immune, health.

We know that gut microbiota are altered by stress, antibiotics, high-fat diet, and a overly clean environment, University of Texas associate professor of pediatrics and gastroenterology Dr. Yuying Liu, who has conducted research on gut bacteria and autoimmunity, recently told The Huffington Post. It is reasonable to postulate that lifestyle interventions could help to prevent or treat autoimmune diseases.

Giving a child antibiotics can be unavoidable in certain situations, but very often its not.Antibiotic misuse is rampant in the U.S., andaccording to the Centers for Disease Control and prevention, one in three antibiotic prescriptions is unnecessary.

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