Antibiotics, Obesity and Other Negative Effects
William B. Miller, Jr. M.D.
discovery of the antibacterial activity of penicillin by Alexander
Fleming in 1929 represents one of the singular moments in human history.
The number of lives saved is beyond calculation. Medicine was
revolutionized by that discovery.
The success of antibiotics is based upon their ability to interfere with
a bacterial growth, metabolism, or reproduction. The manner in which
they work means that many types of bacteria are affected at the same
time by any particular antibiotic, which is termed 'broad spectrum.'
Although often miraculous and life saving, people need to be aware that the use of antibiotics has negative effects.
Deep associations between gut microbial composition and diabetes and
obesity are now being discovered. A recent surprise has been strong
evidence between the administration of antibiotics and increasing
childhood obesity lasting into and through adulthood. It appears that
the more antibiotics you get as a child, the stronger the effect. The
antibiotics seem to be wiping out beneficial populations of gut bacteria
and replacing them with others that are less so. The possibility that
this might also link to the increasing incidence of Type II diabetes is
being further explored.
In the last few decades, the problem of antibiotic resistance has become
an increasingly reported clinical experience. Some antibiotics that had
been effective against a certain type of bacterial infection have
become less so, requiring a higher dosage or more prolonged treatment.
In some cases, they might now demonstrate near complete ineffectiveness
against a bacterial strain against which they had been highly potent
What lead to this unexpected outcome? Commonly, it is stated that the
bacteria have mutated in response to antibiotics. However, that is
largely incorrect. Antibiotic resistance is ancient. All common
antibiotics are based on chemicals found in nature and used by other
organisms to ward off bacteria. Over eons and long ago, bacteria
themselves evolved to counter this form of defense by developing
resistance to those defenses. What is occurring in our modern era is
that our current antibiotic resistance is leading to an increase in the
number of naturally resistant bacteria that become more common within
bacterial populations. It is, in essence, a form of selective breeding
for bacteria, for the wrong type.
Part of the problem is the pressure felt by physicians to offer
antibiotics to their patients. The belief in the power of antibiotics
can be very high among patients who are suffering. Many times, even
though the treating physician might assume that it will not be
effective, the default can be towards satisfying that demand with the
consideration that 'no harm will be done'.
What we are now learning is that this attitude has been an incorrect
assumption. There are other forms of inadvertent harm beyond antibiotic
resistance that can occur and these directly relate to the 'broad
spectrum' capacity of almost all antibiotics. Since they are active
against many bacterial types, there is the suppression or eradication of
many populations of bacteria at the same time, apart from the specific
pathogenic bacterial type that is actually being targeted. When
antibiotics are used improperly, the critical balance of many essential
bacterial partners in our body tissues is being upset. We do this every
time we overuse antibiotics by administering them for the wrong
indication. Permitting their use in our food supply compounds these
types of errors.
This enlarged understanding stems from the fact that all creatures on
this planet including humans are actually vast collaborations between
microbial cells, viruses and our own innate cells. In fact, for us
humans, microbial cells outnumber our own cells by more than 10 to 1 and
are present in all of our body tissues. So when an antibiotic is
administered for the wrong reasons, an exquisite balance between an
enormous array of microbes and our own cells is being altered for no
productive reason. And furthermore, these partnerships between the
microbial realm and our own cells serve vital purposes in our health.
The range of that interaction can be very surprising. They are
intimately connected with our growth and development, metabolism, and
even our neurological function and moods.
What happens then if there is a breakdown of these crucial microbial
partnerships? It is now known that there are very significant
consequences. This has become a well-recognized issue, termed
There are now a wide range of examples of these types of effects. An
increasing number of diseases are now either being directly attributed
to dysbiosis or linked to them. For example, the incidence and intensity
of inflammatory bowel disease is now known to be associated with
intestinal dysbiosis. Cases of a particularly nasty gut pathogen,
Clostridium difficile, are now being actively treated by re-establishing
the proper balance of the intestinal flora. Not surprisingly then,
antibiotics use is now considered to be one risk factor for the
incidence of both of these conditions.
It has been shown that the incidence of both childhood and adult allergy
and asthma is on the rise and some research suggests that this, too, is
related to antibiotic exposure. Other reports suggest associations
between dybiosis and other extra-intestinal diseases such as autism,
schizophrenia, rheumatoid arthritis, colorectal cancer and even a
tentative association with breast cancer.
What should we do with this new information? Clearly, despite some
risks, antibiotics remain essential wonders of our modern medical
palette. However, their use should be carefully tailored by physicians
for only strict indications. Patients and parents must be willing to
accept that antibiotics should not be reflexively requested for many
infectious illnesses. And surely, the use of antibiotics in our food
supply should be very carefully regulated and restricted.
Dr. Bill Miller has been a physician in academic and private practice for over 30 years. He is the author of The Microcosm Within: Evolution and Extinction in the Hologenome.
He currently serves as a scientific advisor to OmniBiome Therapeutics, a
pioneering company in discovering and developing solutions to problems
in human fertility and health through management of the human
microbiome. For more information, www.themicrocosmwithin.com.