The dangers of antibiotic overuse disrupting delicate body balance

The bacterium Enterococcus faecalis, right, lives in the human gut and is just one microbe being studied as part of NIH’s Human Microbiome Project.
The bacterium Enterococcus faecalis, right, lives in the human gut and is just one microbe being studied as part of NIH’s Human Microbiome Project. AP

Antibiotics have saved millions of lives since Alexander Fleming’s Nobel-Prize winning discovery of penicillin 87 years ago this month, but there is a downside, too.

Antibiotics can cure acute bacterial infection, but indiscriminate use might have profound negative effects on our long-term health. More than 70 percent of antibiotics are consumed in factory farming of animals. Our government has been anemic in addressing this threat.

In December 2013, the FDA offered voluntary guidance for pharmaceutical companies that suggested a three-year phase-out of antibiotics in animal feed, a practice known as “growth promotion.” This guidance does not go far enough. The use of antibiotics for factory farming is still widespread, even as some of the largest food manufacturers and restaurant chains have limited the use of antibiotics in their supply chain (Tysons, Perdue, McDonald’s, Chick-fil-A, Chipotle).

The need to curb antibiotic use is an urgent problem, but not only because of antibiotic resistance. We are learning ever more about the integral benefits of the trillions of bacteria we all harbor in our guts. This microbiome works synergistically with its human host to maintain health and well-being. Imbalance or loss of diversity of gut bacteria is now thought to influence mental health, autoimmune diseases and a whole host of other chronic problems.

In fact, it is entirely possible that antibiotics have had a profound effect on the obesity epidemic. We know that when antibiotics are added to their feed, farm animals get fatter. Further, scientists can induce obesity in mice by transplanting gut bacteria.

The healthy diversity of bacteria in our guts has been compared to a rain forest. Clear-cutting the forest decreases its diversity so that it resembles a multi-crop farm. Similarly, every time we take an antibiotic for an acute infection (or to prevent an infection), we are remodeling the balance of bacteria in our body. Individuals should understand the effect that antibiotics have on this delicate ecosystem and should discuss with their physicians how integral the use of antibiotics is in their current treatment.

We need a two-pronged approach to this problem. First, we need to encourage lawmakers to pass bills to remove antibiotics from our food supply. Second, we need greater funding focused on human microbiome research to understand the role gut bacteria play in health and disease. Findings from the NIH’s Human Microbiome Project, the David Lab at Duke University and other similar labs around the world are critical in eradicating some of today’s most vexing diseases.

On this anniversary of penicillin, we should all be thankful for the scientific discoveries that have made it possible to relieve suffering. But we must also remain mindful of the complexity of the human body. Altering a single pathway of such a complex system, as occurs with antibiotic use, is sure to have unintended effects. This reinforces the importance of a holistic approach to medicine, which considers the whole patient rather than reducing their condition to an isolated problem.

Jeffrey M. Taekman, M.D., is a professor of anesthesiology at Duke University Medical Center.