It is not often that I make us of this blog to write about my firsthand experiences. But I’m here today to do just that. Thanks to a slew of antibiotic allergies — for which I broke out in dangerous quantities of hives — I have been limited only to doxycycline-family antibiotics since the mid 1990s. I’ve always wondered since then — with a foreboding sense that I’ve been thrown into the antibiotic dark ages — what would happen in the event my old standby, doxycycline, failed to work in the event of a severe infection. As antibiotics go, doxycycline, like its better-known counterpart tetracycline, is not a new or particularly heavy-duty drug. If anything, this class of antibiotics is seriously overused — ubiquitous in agriculture and dermatology alike.

Recently, I was talking to an old friend and, quite coincidentally, learned that my friend belongs to the same bizarre club: limited to the use of doxycycline, as an antibiotic treatment, because all others have begun to provoke serious allergic reactions. She’s the fourth-such person I’ve met to have become so over-reactive to multiple classes of antibiotics as an adult, and yet anecdotally the trend would appear to be on the uptick. In a recent case, a child not known to be allergic to blueberries made medical headlines after researchers determined that antibiotic residues — not the blueberries themselves — had provoked a life-threatening reaction. It’s not just factory-farmed animals that pose antibiotic-linked health risks. Antibiotics have shown up in corn, potatoes and even lettuce, researchers have found.

At most, I undergo a course of doxycycline once per year — generally in the midst of flu/cold (or holiday) season. In the years since I lost access to all but doxycycline as an antibiotic treatment I have entered the middle-age stage of life, too. Like others, I’ve blamed middle-age spread on “hormones”. It’s a tempting excuse because I am not adverse to fruits and vegetable — I actually crave salads! — and I’ve never been one to go on emotion-driven food binges, either. Additionally, I have never taken up a daily candy, chip, doughnut, bagel, soda, Starbucks, alcohol or dessert-after-dinner habit. In fact, I limit myself to one glass of sugar-free tart cherry juice per day and if I eat a starchy pancake breakfast at all, which is rare, I drench my flapjacks in sugar-free syrup. (I prefer them that way even though I am not diabetic.) I am fairly confident that “empty calories” have been eliminated as a suspect. Like most Americans, however, my exercise habits could stand improvement. I admit: Brief (almost) daily walks with my spouse and my dog just doesn’t cut it. Nonetheless, my list of “usual suspects” gave way to a light-bulb moment of an entirely different sort this year.

What if you were to suddenly appreciate that there’s a much more insidious cause of those annual “holiday pounds” — which tend to correlate, too, with cold-and-flu season?

My wake-up call came this year when, for different reasons, I had to go on three different 2-week courses of antibiotics. In the immediate aftermath of each treatment I added nearly 5lbs, without any other change in my diet or activity level. Curious, I did what a lot of people do nowadays: I began typing terms such as “antibiotics” and “weight gain” into a search engine.

It turns out that what isn’t widely appreciated by most of us, isn’t exactly new.

Oddly — and disturbingly perhaps intentionally so — antibiotic side effects rarely specify weight gain. But the evidence turns up quite broadly in another medical field entirely: veterinary medicine. Dating back to the ~1940s antibiotic use has been observed to cause chickens, destined for our dinner plates, to pack on pounds. In the livestock industry it is routine to introduce such antibiotics into the feed of very young animals — and not just for the reason we might think: the over-crowded conditions in which these factory farm animals live. Livestock producers have been using antibiotics as bulking agents for decades because it is thought to make livestock operations more profitable. And while such practices have raised awareness in recent years over the rise of so-called superbugs — drug-resistant pathogens that do not respond to conventional treatments — what remains far less appreciated is that the obesity crisis may be fueled by much the same practice. The sad reality is, whether we resort to antibiotics all that often to treat illness isn’t the only risk. The average American diet may pose an even more insidious risk. In other words, it’s no longer merely a calories in vs. calories out equation. The chemical soup in which we live — and eat — is our own worst enemy, too, with a record 60 percent of Americans outside of healthy weight limits per the CDC.

Earlier this year I came across an article in which a woman, in her early 30s, became obese for the first time in her life following a fecal transplant. To treat the infection of her gut, doctors harvested bacteria from her overweight teenage daughter’s colon to “restock” her ravaged gut. With no change in diet or exercise she began to pack on pounds. Within a year she reached ~170lbs in spite of a medically supervised attempt to shed the weight. This woman, in her prime — not yet old enough to blame hormonal changes — purportedly was accustomed to working out regularly. She made medical news when all the normal efforts that had kept her trim and fit abruptly began to fail. The phenomena, it turns out, has already been identified in animal research. Studies have shown that implanting the gut bacteria of an obese human into a thin mouse can cause a thin mouse to become obese. This occurrence was unwittingly validated in a human subject, whereas it is not “new news” in the animal research realm.

Researchers have observed that the gut bacteria in humans and animals that are obese are dominated by some strains of bacteria whereas other strains that ought to be present are far fewer in number. Maintaining a diverse bacterial balance is largely responsible for immune health and even the uptake of nutrients from the digestive tract — which may also explain why researchers also find that obese people are paradoxically micronutrient deficient. And now researchers have evidence, too, to suggest the battle of the bulge begins in the gut. When you think about it, is that any surprise? We all know people who seem to be able to eat anything they want — without a particularly vigorous approach to exercise, either — and yet they don’t pack on pounds as the years pass. For that good fortune, we tend to credit genetics.

Perhaps we should instead credit them with a healthier gut?

That’s not to say that the usual suspects — a sedentary lifestyle or a convenience-food diet — do not play a role. And it does not change the fact that healthy weight maintenance can become a challenge as we age under the best of circumstances. Young people, in general, benefit from a faster baseline metabolism thanks, in part, to a better muscle-to-fat ratio, whereas it becomes difficult to maintain calorie-burning muscle mass without considerable effort as we age. Still, what also changes as we grow older here in the developed world is that most, if not all of us, have ingested that many more courses of antibiotics. Cumulative exposure to antibiotics is the corollary that, by far, is a lesser appreciated aspect of the health-lifestyle picture. Crueler still, changes in the microbial balance of the gut can precipitate cravings for all the wrong things. In essence, out-of-whack gut bacteria may play a role in prompting the consumption of foods that only make their numbers grow larger (e.g. starch). We may think we are the brains of the operation, biologically speaking, but in reality the billions of microbial colonies that reside in each of us call a lot of the shots — for better in some, for worse in others.

Antibiotic use has proliferated over the past ~70 years — in tandem with the obesity epidemic. That’s not to say that antibiotics are solely responsible for the trend. During those same decades we’ve also seen the dual-income household become the norm — and with it the rise of prepackaged foods, the fast food industry and the TV dinner. All the while, we have also seen a proliferation of desk-bound professions, too, thanks to advances in technology. With an Internet connection and a computer, after all, it is not even necessary to get up and physically go to a library or a brick & mortar store to do one’s shopping. So, again, the obesity epidemic is not singularly tied to antibiotic use. Moreover, antibiotic use to treat or prevent dangerous illnesses is in many cases more lifesaving than waistline-endangering. Even so, when you take the changes in how we work, how we eat and how much antibiotics we consume throughout our lives as compared to 60+ years ago, it may very well add up to a Perfect Storm.

While not everyone will pack on 2, 5 or even 10lbs in the wake of antibiotic treatment, repeated assaults upon one’s microbial balance over the course of a lifetime would appear, at least among some individuals, to correlate to “weight creep”. It’s never a bad idea, of course, to add miso, sauerkraut, kefir and other such pre/probiotics to one’s diet. But so far it’s not clear if dietary modification, alone, can cancel out risks associated with antibiotic overuse.

The fact is, antibiotics have been recognized as growth agents for many years within the livestock industry. And yet decades after scientists first began to note the phenomena, the connection between antibiotics and weight gain among humans is less appreciated among medical doctors and pharmacists as compared to their counterparts in veterinary medicine.

Why does this disconnect persist?

By all appearances consumers have been prevented from making informed health decisions with respect to an antibiotic-obesity connection. One mistake on the part of the medical community is to neglect the fact that antibiotics are in our food supply — and not just in meat and dairy but, thanks to the practice of using antibiotic-tainted fertilizers in agriculture, in food commonly perceived as “clean”. Another mistake the medical community has made over the years is to assume that because antibiotics are generally prescribed for short-term use, adverse side effects will be self-limiting too. But we now know that’s not necessarily true.

It’s one thing to make use of antibiotics to prevent post-surgical infection, to treat a bad case of bronchitis or to heal an abscess. It’s another thing, however, for physicians to recommend long-term antibiotic use for non-lifesaving uses. The American Medical Association, at minimum, should put out an advisory to compel dermatologists — who routinely make use of long-term antibiotic therapies — to inform patients of the weight-gain risks. Family practitioners, too, should make a point to compare patient before/after weight as a routine part of antibiotic administration.

As some readers may recall, the charge back in the 1990s during the infamous Big Tobacco trials was that cigarette producers had intentionally attempted to make products more addictive while covering up decades-worth of knowledge that cigarettes and lung cancer risk go hand-in-hand. Perhaps a similar cover-up is going on within the pharmaceutical industry on the part of antibiotic manufacturers. For a certain percentage of the population, smoking a pack a day will never result in cancer and/or heart disease. But for a whole lot more, it will. Similarly, for a certain percentage of the antibiotic-ingesting population weight gain will not materialize. But for many more people, it may do just that. And don’t think for a second that antibiotic producers don’t appreciate the link between antibiotic overuse and overweight — even if your physician or pharmacist does not.

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Resources

Antibiotics Might Be Fueling the Obesity Epidemic | Wired Magazine