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How do gut bacteria support the immune system?
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Bacteria
A scanning electron micrograph of gram-positive Mycobacterium tuberculosis bacteria, the cause of tuberculosis and scrofula.
Gut bacteria play a vital role in supporting the immune system through several key mechanisms:
- Immune Regulation and Development: From infancy, interactions between intestinal microbes and immune cells help the body learn to distinguish between harmless microorganisms and disease-causing pathogens. These interactions also assist in regulating inflammatory responses.1
- Colonization Resistance: Beneficial bacteria provide a protective effect by competing with harmful microbes for nutrients and attachment sites. Additionally, they secrete proteins that inhibit the growth of invading bacterial species, helping to prevent infection by pathogens such as Salmonella and Clostridioides difficile.12
- Reinforcing the Intestinal Barrier: Through the fermentation of dietary fiber, gut bacteria produce short-chain fatty acids—such as acetate, butyrate, and propionate—which provide energy for colon cells and help reinforce the intestinal barrier, thereby mediating systemic inflammation.1
By maintaining a balanced microbial community, these bacteria help the body maintain homeostasis and defend against external threats.1