Antibiotics: The Troublemaker for Our Intestinal Flora

If you Google the terms “antibiotics + gut”, you will not only be confronted with more than 3.5 million results, but you will also realize that this topic apparently moves a lot of people, such as Dr. Sofia Förslund from the Max Delbrück Center for Molecular Medicine in Berlin.

Antibiotics – What You Need to Know

When we talk about “antibiotics”, we mean drugs used to treat bacterial infections. Their function is to inhibit and/or kill “disease-causing” bacteria in the human body.

While antibiotics are not effective against fungi or viral illnesses such as influenza or measles, antibiotics are often prescribed for bacterial illnesses such as scarlet fever or pneumonia/tonsillitis. The catch? Not only the supposed pathogens, but also the beneficial bacteria that live on our skin or mucous membranes come into contact with antibiotics. Possible consequences include

  • various side effects
  • allergic reactions
  • development of resistances
  • risk of multidrug resistance
  • long-term damage to the microbiome

Negative and Long-Term Effects on the Microbiome

At the Max Delbrück Center for Molecular Medicine (MDC) in Berlin, the Swedish researcher studies the interactions between humans and the microbiome (intestinal flora) and how broad-spectrum antibiotics affect the interaction of intestinal bacteria. Together with her international team, she was able to show in a study that about six months after taking antibiotics, the microbiome had almost recovered, but not completely, because some of the former bacterial species were missing. “As expected, the number of resistance genes in the bacteria had also increased,” says Dr. Förslund.

This negative influence on the microbiome was also confirmed by a study conducted by the Marine Biological Laboratory in collaboration with Stanford University (Woods-Hole study; Palo Alto, California). The study found that before taking antibiotics, participants had between 3,300 and 5,700 different types of bacteria in their guts. After taking the antibiotics, the number dropped by one-third. All of the other types of bacteria changed in quantity in such a way that a so-called dysbacteria existed. The balance of the intestinal flora could not be restored within four or six weeks because some bacterial strains did not recolonize.

The Balancing Act for Our Gut

But why is the diversity of bacteria and the balance in our microbiome (= intestinal flora) so important?
To answer this question, it is important to know that our gut is basically our second brain. 90% of the visceral nerve alone is located in the gut and transmits this information to our brain, which in turn interprets it as emotions. But the immune system is also largely located in our microbiome: about 80% of all immune responses take place there, and about 70% of immune cells are located in our largest organ.

Out of Rhythm with Antibiotics

When our gut flora becomes imbalanced, we can experience intestinal problems, food intolerances, overweight, obesity, autoimmune reactions, a weakened immune system, and even psychological disorders.

Taking antibiotics often starts a vicious cycle: Starting with a weakened immune system, infections or fungal infections often follow after a few weeks, which in turn need to be treated with medication.

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