Antibiotics enable much of the lifestyle we’ve grown accustomed to on planet Earth. An infected wound or case of syphilis or any of the other great many sinister things caused by bad bacteria are no longer things that carry a very real possibility of imminent painful death. Just that fact has made all the difference in our world in terms of life-span and quality of life. If a dog bites you or you step on a rusty nail, death is no longer a probable result. That’s great. Things that are great, however, tend to be overused, and antibiotics are no exception.
In addition to stopping various multiplying pathogens racing around your blood stream or clinging to vital organs or partying in dirty wounds, antibiotics are routinely used for such things as clearing up acne and “curing” colds that are probably not actually related to bacterial infection in the first place. In fact, the CDC estimates that up to half of all antibiotics delivered in a hospital setting are unnessessary. And antibiotics are used in agriculture, in part to reduce the chances of foodborne illness, but also to promote growth in animals. Though we’ve had very little idea as to why they actually do this until a recent discovery made at the NYU School of Medicine.
According to a paper out today in Nature that answer, rather unsurprisingly, has to do with how antibiotics work on the body’s good bacteria, particularly the bacteria that make up the gut microbiome. (This impact is why taking antibiotics can have certain gross digestive repercussions.) This community of bacteria is crucial to a whole lot of things in your body, including even your mental state. And the sum total of impacts an organism might experience from having its gut bacteria posse disrupted, particularly long-term, is still somewhat of a mystery. The new study points to how that disruption might affect things like metabolism and how an organism fights disease. It’s not good.
The system in which livestock are given antibiotics is called STAT, or subtherapeutic antibiotic therapy. The researchers administered STAT to lab mice and, as a result, the mice increased in body fat mass and overall percentage of body fat, up to 15 percent. In addition, the mice were found to have an increase in bone density and, crucially, had some of their metabolic hormones sent out of wack. Which potentially has a lot more implications than just making fat organisms — like preventing neccessary nutrients from being used properly by the body.
“It is possible that early exposure to antibiotics primes children for obesity later in life.”
“By using antibiotics, we found we can actually manipulate the population of bacteria and alter how they metabolize certain nutrients,” said Dr. Ilseung Cho, the paper’s lead author. “Ultimately, we were able to affect body composition and development in young mice by changing their gut microbiome through this exposure.” In effect, they were able to make fat mice with growth problems. The implication is that widespread antibiotic use in humans is doing a similar thing to our children — making them fat and ultimately less healthy, in addition to increasing their resistance to antibiotic treatment and helping to create new strains of drug-resistant bacteria (like MSRA).
“This work shows the importance of the early life microbiome in conditions like obesity,” said Martin J. Blaser, MD, the study’s lead investigator. “The rise of obesity around the world is coincident with widespread antibiotic use, and our studies provide an experimental linkage. It is possible that early exposure to antibiotics primes children for obesity later in life.”
This is potentially huge. Obesity — or, rather the health issues that often result from it — is a massive public health issue, and is expensive as all hell for society to deal with. Proving this link is going to take a lot more than just this one study, but it would be interesting to see some comparions of obesity rates in different localities and rates of childhood antibiotic use. As that 50 percent figure cited above should attest, this is a situation where we really can have it both ways: we can use antibiotics well enough to keep us several steps above the dark ages, but we can also stop using them like penicillin is water. A bit of proof that antibiotic use is making us fat would go a long way.
Also, given that the gut microbiome helps determine pretty much everything else in the body, expect many more antibiotic links to be made in the future. And there probably aren’t a whole lot of antibiotic effects left to be discovered that are good. Which doesn’t make the crucial live-saving sorts of things antibiotics do any less crucial and life-saving. That’s something to keep in mind, particularly if you have heavy contact with particular crowds looking for valuable medications to declare totally evil.