Written by William Davis, MD

Have you ever taken an antibiotic for a urinary or upper respiratory infection? Most of us have, given the fact that 800 antibiotic prescriptions are written for every 1000 Americans every year. By age 40, most Americans have taken 30 courses of antibiotics.

By taking antibiotics, you join the huge number of Americans who have disrupted their intestinal microbiome, i.e., the composition of microbes that dwell in the human gastrointestinal (GI) tract. Many healthy microbial species that are meant to occupy the human GI tract are eradicated by, say, a 10-day course of ampicillin for a sore throat. There are microbial species that are important players in human health that are lost with a single round of an antibiotic.

The Centers for Disease Control (CDC) estimates that over a third of the antibiotics prescribed are unnecessary and provide no benefit. It might be a prescription for ciprofloxacin for a viral upper respiratory infection for which antibiotics have no effect. Or a course of azithromycin for a fever without an identifiable source. In the nearly 100 years since Dr. Alexander Fleming discovered the world’s first antibiotic, penicillin, in 1928, antibiotics have become an all-too-familiar accompaniment to modern life — but one that comes with a substantial health price. 

One of the microbial species most susceptible to common antibiotics is Lactobacillus reuteri, named after the German microbiologist, Dr. Gerhard Reuter, who first identified it in 1962. Performing his investigations in the 1960s until the 1980s, Dr. Reuter remarked how L reuteri was a common microbe in the microbiomes of people when he first began his research, only to become uncommon towards the end of his career studying bacteria. A recent survey to identify how many people still harbor this species found it lacking in 96 percent of people studied.

L reuteri is a microbe that has been recovered from the stool of indigenous human hunter-gatherer populations unexposed to antibiotics, such as people living in remote areas of New Guinea without access to running water, toilets, supermarkets, and, of course, antibiotics. L reuteri has also been uncovered from most mammalian species—chipmunks, squirrels, possums, dogs, as well as non-mammalian species such as chickens. But most modern humans have lost this microbe and thereby the advantages it provided.

What makes this particular microbe so important is that, when restored, it takes up residence in the entire length of human GI tract, then sends a signal to the brain to release the hormone oxytocin, the hormone of love, affection, and empathy. It is the hormone that brings you closer to your partner, family, co-workers, and helps you understand the opinions of other people.

Indeed, the thousands of people who have restored this microbe report feeling closer to their partner and families, feeling closer and less annoyed by co-workers, experiencing less anxiety in social settings, becoming better able to understand the opinions of people whose views differ from yours. In other words, the boost in oxytocin makes you more social, more loving, more understanding — a better human being.

As powerful as these social and emotional effects can be, there is another dimension to the effects experienced with restoring this L reuteri. Not only are you a nicer, more understanding, person, but many people also develop smoother skin because of increased dermal collagen, experience a return of youthful strength and muscle, experience deeper sleep and increased libido, have reduced appetite, an improved immune response, and accelerated healing from an injury or wound. Smoother skin, greater muscle, better sleep and libido, improved immunity — doesn’t this all add up to turning the clock back a few decades? I think it does. And these are the benefits of restoring just this one microbe.

L reuteri is one of many microbial species that we can restore with some pretty spectacular effects. You can restore a microbe that, for instance, reduces arthritis pain, or a microbe that shrinks your waist, or helps a newborn experience improved neurological development, sleep through the night, and have less asthma, skin allergies and have a higher IQ as an older child.

If this and other ways to manage the universe of microbes that inhabit your body by applying strategies that go way beyond “take a probiotic and get some fiber” interest you, then I invite you to take a look at my new book, Super Gut: The Four-Week Plan to Reprogram Your Microbiome, Restore Health, and Lose Weight.

William Davis, MD, is the #1 New York Times bestselling author of the Wheat Belly series of books. His newest book is Super Gut: The Four-Week Plan to Reprogram Your Microbiome, Restore Health, and Lose Weight, the book that provides a roadmap on regaining control over the human microbiome to enjoy unprecedented health, weight, and emotional benefits.