Antibiotics are over-prescribed in modern societies, and this has become a significant health problem. A 2000 study by Richard Wenzel and Michael Edward found at least half of all human antibiotic use is unnecessary. At least 25% of the time patients are prescribed antibiotics for conditions which they aren’t able to treat, such as viral infections. They are often prescribed when a doctor isn’t certain about the cause of a particular illness. And they are prescribed too quickly in cases where a patient’s immune system could have cleared the infection on its own.

Another problem is the “overuse of broad-spectrum antibiotics both in situations where a narrower alternative would be appropriate and in situations where no therapy is indicated at all,” says Adam Hersh, assistant professor of pediatrics at the University of Utah. (Reddy, 8-20-2013) His research found doctors prescribe broad-spectrum antibiotics around 60% of the time.

Antibiotics & your microbiome: Why over-using antibiotics is harmful
Over-using antibiotics speeds up the rate at which pathogens develop resistance, leading to more antibiotic resistance and the emergence of antibiotic resistant “superbugs.” It also adversely affects your health. Antibiotics don’t just attack the bad bacteria, they kill the good ones, too. Most of the time these populations can recover, since they aren’t completely wiped out, and unlike the harmful microbes who will be picked off by T-cells once their numbers are reduced, beneficial bacteria aren’t targeted by your immune system. But repeated assaults on your microbiome isn’t healthy, and people can lose some of this microbial diversity when antibiotics are overused.

Martin Blaser, a physician at New York University School of Medicine, suspects that this is having a cumulative effect, worsening our health from one generation to the next. So for example, let’s say your microbiome has been damaged just a bit by the overuse of antibiotics. You then pass this diminished microbiome down to your children, who then experience their own assaults that knock it down further. After successive generations the number of beneficial bacteria is greatly reduced.

Case in point: anthropological research has shown a stark decline in the microbiome diversity among modern populations. “We are losing diversity, and in parallel there is a correlation with increase in chronic diseases,” says microbiologist Maria Gloria Dominguez-Bello. A 2007 study in Science found that the more industrialized a society, the less diverse the microbiomes of its people. Those living in the U.S, for example, possess just half of the microbiome diversity seen among the most isolated Indians living in South America. This has led some scientists to call for a microbial “Noah’s ark” to try and preserve this diversity before it’s too late. (Beans, 2020)

Not all of this decline in the health of our microbome is the result of antibiotics. Some of it can be linked to other environmental factors, such as modern diets, a lack of time spent outdoors in nature, overly sanitary environments, and c-section births. But the overuse of antibiotics certainly plays a role.