How do antibiotics destroy our gut health?

Antibiotics are substances that are either produced through the use of microbes such as penicillin-producing bacteria, extracted from plants, produce entirely industrially, used to prevent the growth of microbes or slow their growth and reproduction, but there is growing concern among scientists about the health implications of our growing dependence on antibiotics.

Our bodies contain bacteria estimated to number in the trillions. Highest density of which is found in our gut. But do we permanently damage this vital part of our body every time we take antibiotics?

Dr James Kinross, consultant colorectal surgeon at Imperial College London, said: "The microbes that live in the gut form a complex network of microorganisms and all the things they need to survive within the body.

The microbes that live inside the gut play a big role in keeping us healthy. Healthy, including regulating the immune system and facilitating digestion.

Experts say antibiotics are one of the most dangerous things for our gut microbes.

According to the BBC, antibiotics, prescribed by doctors to treat or prevent bacterial infections, are a cornerstone of modern medicine. But in the process of targeting the bacteria that cause infection in our bodies, antibiotics can also inadvertently kill other bacteria in our bodies.

There are growing concerns among scientists about the health implications of our growing reliance on antibiotics. Between 2000 and 2015, the number of antibiotic prescriptions increased by 65 percent. The problem with this growing use of antibiotics is twofold: damage to our gut microbes, and growing antibiotic resistance of bacteria.

Professor Gautam Dantas, Professor of Laboratory Medicine and Genetic Genomics at Washington University School of Medicine in St. Louis, US, said: "Antibiotics disrupt the balance of the entangled ecosystem of microbes that inhabit our guts and thus increase the risk that surviving bacteria will donate their genes to pathogens."

We know that the more diverse the colony of bacteria that live inside our guts is, the better for our health. But of course, antibiotics disrupt that colony because they don't specifically target the pathogenic bacteria that cause the infection, but all the bacteria in our gut.

"Imagine that there's a forest trying to eradicate one of its weeds," says Dantas. "The way we use antibiotics is like a massive bombardment of that forest, destroying both harmful and beneficial weeds indiscriminately."

Dantas says that when scientists studied the microbes that live in the intestines of infected people before they took a therapeutic dose of antibiotics, they discovered that the multiplicity and diversity of those microbes recovered after several months. But in some people, some types of good bacteria never return to their bodies.

Dantas and his research team have been studying stool samples taken from children treated at a children's hospital, where there is a scientific collaboration with his laboratory. These samples were collected on a regular basis, before and after the children became infected or took antibiotics, which allowed his team to monitor changes in the bodies of children who become infected and later treated with antibiotics.

Dantas used these samples to compare changes in gut micro biota after antibiotics in two infant groups: a group of premature babies born prematurely before 36 weeks of gestation and a group of babies born after 36 weeks of gestation.

"What we know happens in adults after taking antibiotics happens much more in newborns: less diversity of microbes living in the body, and a huge rise in drug-resistant genes," he says.

While the effects vary from person to person, depending on our age, there is a consensus among scientists that the effects of taking a single dose of antibiotics can be permanent.

"Some people are at high risk of damage to their microbes from taking antibiotics, and their environment changing dramatically and not returning to what they were before the antibiotic dose," says Kinross.

In our gut, we are losing diversity and plurality at an unprecedented rate, as well as vital bacteria that have been defending us for tens of thousands of years.

The paradox behind antibiotic use is that with every therapeutic dose we take, there is a possibility that we will undermine our body's ability to fight infection, and consequently, our dependence on antibiotics will increase.

"It is better not to have to rely on antibiotics, but instead focus on the resilience of our internal ecosystem through a healthy diet, especially in the early stage of a person's life, as it is the stage where antibiotics cause the greatest harm," asserts Kinross.

But scientists are still trying to understand the long-term health implications of antibiotics on the microbes living in our gut.

Antibiotics not only reduce bacteria, but they also influence microbial functions in complex and unique ways that we don't fully understand. "We know that antibiotics have the capacity to affect all areas of the functions of our microbes.

He adds that not only is the effect of antibiotics on gut bacteria is a concern, but also additional implications for immune system development.

Studies show that repeated doses of antibiotics have a cumulative effect, and the effect is greatest when you take a dose with a wider spectrum.

Dantas says those random doses "will kill an important microbe now and then. It's an evolutionary experiment that we do on ourselves every time we take an antibiotic."

Another consequence of long-term use of antibiotics is the risk of drug resistance. When a colony of bacteria is exposed to an antibiotic, species that lack antibiotic-resistant genes perish. The types of bacteria that carry these genes — genes that may have been obtained from their environment or through spontaneous mutations — survive. This is a problem when pathogenic bacteria take advantage of it.

"Every time we use antibiotics, the relative risk of gut microbes acquiring drug-resistant genes increases, so when a pathogenic microbe infects the body, it may be able to pick up some of those selective genes from the gut," adds Dantas:

This process is not limited to our gut, says Professor Craig McLean, professor of evolution and microbiology at the University of Oxford: "Resistant bacteria can migrate from the gut to other places, so what happens in the gut affects the rest of the body."

The harmful effects of antibiotics and their life-saving ability are among the biggest dilemmas that baffle scientists around the world. While there is no solution to this dilemma, there are some approaches that may mitigate the adverse health effects of antibiotics.

"Antibiotics are wonderful drugs that have saved millions of lives. They are very precious resources and should be used, but we need to understand how we can direct them precisely."

Scientists are currently studying the possibility of creating antibiotics that target specific parts of the body, and others that target specific bacteria, McLean said, and the idea is to get rid of only the bacteria we want to get rid of and not to harm the good bacteria in our gut.

But as Professor Anthony Buckley, associate professor of microbial science at the University of Leeds, says, the biggest tool we have at our current disposal is our diets: "Nutrition is one of the biggest factors that help build colonies of beneficial microbes within the human body."

The University of Leeds' Infection Research Group has been testing the effects of antibiotics on microbes living in the human body for the past two decades.

The wide variety of foods we eat is usually associated with a great diversity of microbes in the gut, and dietary fiber in particular seems to have a positive effect, says Dr. Inés Mora, a researcher at the university's School of Medicine and Health, who is currently researching the effects of different nutrients on the microbes that live in the gut and how they can reduce the negative effects of antibiotics.

Buckley says dietary fiber is especially important because the microbes that live in our bodies digest it and produce short-chain fatty acids that provide energy to the cells lining the colon.

"When you take antibiotics, the microbes that produce short-chain fatty acids are depleted and take time to get back to normal. ”Our theory is that by eating dietary fiber, we provide microbes with the essential substance that helps them grow and produce short-chain fatty acids, in the hope that balance will be restored."