Antibiotics may not only harm healthy gut bacteria but also have short- and long-term effects on a person’s health. For example, they can reduce gut flora diversity and affect digestion.
Sometimes, antibiotics are necessary to treat a bacterial infection. However, in the process of killing harmful bacteria, antibiotics can also damage the beneficial bacteria that live in the gut.
Researchers are still learning about the implications of this.
This article explores whether antibiotics harm gut bacteria, which types are most harmful, how they affect health, and how to protect the microbiome while using them.
Yes, antibiotics can harm a person’s gut flora, including the “good” species that benefit human health.
The gut contains many species of bacteria, viruses, fungi, and other microbes. Scientists associate a high diversity of species with a healthy microbiome. Low diversity has associations with a number of health conditions.
Review authors link low microbial variety with intestinal inflammation and disrupted intestinal barrier functioning.
Research on how quickly antibiotics affect the microbiome, and how permanent the effects are, varies significantly.
The 2020 review also notes that age is a factor. It asserts antibiotics during the first 18 months of life cause the most disruption.
The effects of antibiotics on gut health may depend on:
- the type of antibiotic
- length of antibiotic course
- how many previous courses a person has had
- the person’s gut health before they began taking the antibiotics
Repeated antibiotic treatment may prevent a full recovery from ever occurring.
A 2015 study explored the effects of four common antibiotics across fecal and saliva samples. The antibiotics were:
Clindamycin significantly reduced fecal microbiome diversity for up to 4 months. Ciprofloxacin reduced fecal microbiome diversity for up to 12 months.
There was only a short-term reduction in the saliva samples immediately after exposure to ciprofloxacin.
Researchers found a significant reduction in microbiome diversity in fecal and saliva samples directly after exposure to minocycline.
Amoxicillin had no significant effect on microbiome diversity in either sample.
There are many types of antibiotics, though, so this is not a comprehensive list. People may need to research the specific type they are taking or ask their doctor to understand the risks.
Antibiotic-related gut bacteria changes can have negative implications for a person’s health, including:
Researchers define antibiotic resistance as a bacterium’s ability to elude the effects of certain antibiotics that usually inhibit or eradicate other bacteria from the same species.
Clostridioides difficile (C. diff) is a harmful type of bacteria that lives in the intestines.
Usually, other microbes can keep C. diff under control, but antibiotics can allow the bacterium to grow. This
Antibiotics may affect digestion. The
A 2010 study with Danish children reported that the likelihood of developing IBD was highest in the first 3 months after taking antibiotics. The risk was highest in children who had received at least seven courses of antibiotics.
Changes to the immune system
The microbiome influences the immune system, both of which develop at the same time during infancy. Disruption of the microbiome, particularly in childhood, may then affect how well the immune system functions.
Further research in humans is necessary.
There are practical steps people can take to protect their gut health when taking antibiotics.
However, the type and dose of probiotics are important.
Probiotics are not without risks. People should ask a doctor about the pros and cons before taking them.
Prebiotics are substances that feed bacteria. A
Learn more about what to eat when taking antibiotics.
The best way to avoid the negative effects of antibiotics is to minimize exposure to them. This means doing the following:
Avoid unnecessary antibiotic use
Preventing bacterial infections can reduce the need for antibiotics. The same is also true for viral illnesses.
Although they are not bacterial to begin with, bacterial infections can start as a complication of colds and flu.
To prevent contracting and transmitting these illnesses:
- Wash hands with soap and water for
at least 20 secondsafter using the bathroom and before preparing or touching food.
- Use hand sanitizer that contains at least 60% alcohol when handwashing is not possible.
- Cover the mouth and nose with tissue when coughing or sneezing.
- Stay home when sick.
Use antibiotics only when necessary
Sometimes, antibiotics are necessary, even when a person tries to avoid them. People may need antibiotics for an infection that is spreading or getting worse, or for life threatening conditions, such as pneumonia and sepsis.
Doctors may also prescribe antibiotics for people who have a high risk of developing serious infections, including:
According to the
However, each individual should speak with a doctor to determine the best course of action.
Antibiotics have links to antibiotic resistance, reduced microbial diversity, allergies and eczema, metabolic conditions, and digestive conditions, such as IBD. The changes in gut flora composition can be short term but can also be long term.
People concerned about antibiotic use can speak with a doctor about the benefits and risks.