You probably think of antibiotics as life-saving medicines that can cure everything; you name it. From fevers and flu to ear aches and colds, antibiotics are a god-send. Except, of course, that they are really not good for fevers, flu, ear aches or colds, which are largely caused by viruses, which we don’t really know how treat except to let them run their course.
That doesn’t mean that we don’t treat those things with antibiotics. We do. But antibiotics are only good at killing bacteria, not viruses. The reason to use something that is completely ineffective is partly because doctors are tired of arguing with patients (who are not interesting in letting something “run its course”), and they sometimes give in. As my doctor is always reminding me: patients are annoying and needy.
Antibiotics only work on bacteria (the sausages), not viruses (the bug upper left).
So we over-treat with antibiotics – big deal, right? Well, except that it can lead to antibiotic resistance. This is when a bacteria comes up with a way to defeat the antibiotic using a sort of high-speed evolution. When you use antibiotics inappropriately, you inevitably kill bacteria that were just minding their own business. You also kill some of those that were doing you a big favor by keeping something worse at bay. Nastiest of all, you can create bacterial ghettos that have developed resistance – and might not be so benign.
When low doses of antibiotics are used for a long time, bacteria aren’t always killed outright and – because they multiply like mad – they have many chances to try to defeat the drug. Bacteria are very loose with genes, and they can actually steal resistance genes from other bacteria by simply eating them. These guys know how to evolve.
Resistance also arises when people feel better and then quit taking their antibiotic before all the germs are dead. Those that last the longest may have evolved some resistance. You feel great, but you may have created a rebel force in your own body that is just waiting for your immune system to get distracted and then wham! When you least need it, you get something like MRSA (Methicillin-Resistant Staphylococcus Aureus) or my personal favorite, flesh-eating bacteria.
But a little resistance never killed anyone, right? Well, except for at least 23,000 people that we know of each year, and probably closer to 100,000. According to the CDC, 2 million people a year get a nasty infection with one antibiotic resistant bug or another. Treating them is a major headache for hospitals. We are running out of antibiotics that can kill these super-germs.
But our own mindless self-infliction isn’t the only problem with antibiotics. The truth is much more irritating because we have no control over it: the biggest users of antibiotics – by far – are cows, pigs and chickens.
Are we getting resistant bugs from our meat? The studies aren’t conclusive, but they are strongly suggestive: in countries where they trace antibiotics in animal feed (unlike the US, where no tracking is required), the bacteria that are targeted in the animals also show up – in resistant form – in the guts of the consumers. When the antibiotics are pulled out of animal feed, the corresponding resistant bugs disappear in the population.
As compelling as these studies are, they are epidemiological – not the gold standard of a controlled study. Citing this lack of controlled studies, the meat industry claims that antibiotics are safe. And, assuming you cook everything properly, you should be killing all the resistant bacteria anyway. But the epidemiological studies are hard to ignore. Somehow, it seems, the resistant bacteria are sneaking off the farm.
A stronger connection can now be made between farm animals and their close human neighbors. From an ecological point of view, it’s a smart idea to use animal manure to fertilize crops, returning nutrients to the land. But when the animals are on continuous antibiotics, their manure contains antibiotics too, and then it may be a bad idea. The people who live near crops that are fertilized by pig manure suffer higher rates of infection by MRSA.
So that’s not good, but that may not be the worst of it. Have you ever wondered why they feed antibiotics to animals? Are they all sick? Well, when farmers stack up the animals in tight quarters, they do get sick. A lot. And good old fashioned veterinary care is part of the rationale for antibiotics. But the real reason that animals are continuously fed a low dose of antibiotics is a bit of an industry secret: it makes them grow faster.
Why? Although bacteria, once established in the gut, are useful to digestion and normal GI health, there are two ways that they can cause trouble. First, the gut needs to make sure that it is prepared with mucus and other defenses to keep new bacteria away from the cell lining, and that requires some energy. Second, the animal needs to routinely mount immune responses against the bad bacteria that breach that protection. The theory is that providing low doses of antibiotics ameliorates this situation, and with less gut trouble to attend to, the animal can grow faster.
Interestingly, the same trick works for humans, too. Think of it: although you kill bacteria when you cook food, do you destroy all the antibiotics as well? If not, then farmers aren’t just fattening their livestock, they are fattening you as well.
You might think that putting antibiotics in animal feed is new, but look at this quote from an article titled Public Health Significance of Feeding Low Levels of Antibiotics to Animals, written in 1973:
“The feeding of low levels of antibiotics to farm animals … was introduced experimentally in 1949 and commercially in 1950. Chlortetracycline, oxytetracycline, penicillin, and streptomycin were the first to be used, and other antibiotics, especially bacitracin and tylosin, soon came into use. The initial use of low-level antibiotic feeding was to promote growth of chickens, pigs, and calves.”
So, since 1950, we have all been on the second-hand end of a grand experiment to determine how fast and cheaply we could fatten up farm animals. Antibiotics work like a charm.
While the farm animals were plumping up, there was a corresponding increase in the average American waist line. Admittedly, we didn’t keep very good records on obesity until the 60s, but that was mostly because it wasn’t a big problem before then. Again, this is correlation, not causation, but it gives one cause to pause.
Today, 80% of all antibiotics sold in this country are used in farm animals. Where does all that go? It breaks down to 10% for treating sick animals and 90% for weight gain. That’s an alarming figure, because it doesn’t take a lot of antibiotics for weight gain: just a slow drip will make an animal grow bigger, faster. It implies that a staggering number of farm animals are receiving routine antibiotics. We don’t know exactly how many, however, because in the United States, antibiotic drugs are not tracked by any government agency.
Just a slow drip. When you add up all the meats we eat, it is not hard to imagine that we are getting a low maintenance dose of antibiotics as well. We may be having the same reaction: faster growth and weight gain. The fat of the land may be turning us into the land of the fat.
Selman Waksman, the scientist who discovered several antibiotics for farm animals.
This is a story that started with good intentions. Antibiotics have made the world a much safer place. Alexander Fleming discovered the first one, penicillin, in 1928. Selman Waksman discovered many other antibiotics in the early 1900s, including streptomycin, which was the first drug to cure tuberculosis. Routine use of antibiotics has cured dozens of diseases that plagued farm animals. Putting antibiotics into animal feed seemed like a great way to stop opportunistic infections, increase meat production and feed a hungry nation.
Eliminating so many communicable diseases allowed farmers to cram animals ever closer together. Because they are all being dosed, they can wallow in poop all day without coming down with something dreadful. And that helps to bring down the cost of meat, even as it raises the level of disgust about how we do it.
If you’re concerned about these problems, look for labels that say
- No antibiotic use
- no routine antibiotic use
The second label is to designate that on occasion, antibiotics are used to treat illness on these farms. Even so, the farmer using this label must provide a waiting period in order to flush out the antibiotics. That waiting period provides an interesting insight. It demonstrates that farmers are concerned that antibiotics remain in the flesh for some time, and they might make it into humans.
You’re going to have to pay to get rid of antibiotics. These animals can’t be as tightly packed and you will have to reimburse the farmers for that extra room. But it’s worth it if you want to opt out of the antibiotics being unwittingly prescribed for you by your farmer. We should declare this experiment successful: antibiotics can make all of us grow bigger faster. Now let’s stop it.
Earlier, I mentioned that we have no control over this, and it’s mostly true. You can talk to your congresspeople until you are blue in the face. People have been trying to ban routine antibiotic use for over forty years. The lawmakers have been briefed, so they know how dangerous the practice is. There has been progress in Europe. But American politicians need a lot of money to get elected, and the farm lobby is one of the biggest and richest in the world. Faced with such persuasive piles of money, very few politicians can find the courage to stand up to them. It’s a hard problem, but we shouldn’t give up.
We should, at a minimum, vote the bums out. But we should also show the animal industry that we are catching on to their tricks, and we should buy antibiotic-free foods whenever we can (that’s what your congresspeople are doing!). This money thing can work both ways. It may cost a bit more in the short run, but in the long term, the savings from being thinner and therefore less prone to heart disease and diabetes will more than compensate. Oh yeah, you’re also less likely to get a horrible disease caused by some rogue antibiotic-resistant bacteria.
The animal industry may not have a heart, but it has a very sensitive wallet. Once they realize their customers value healthy food over mere bulk, they will come around. It is time, dear reader, to take back our health!
Resources
Sieburth, John McN, Jose Gutierrez, James McGinnis, Joel R. Stern, and B. H. Schneider. “Effect of Antibiotics on Intestinal Microflora and on Growth of Turkeys and Pigs.” Experimental Biology and Medicine 76, no. 1 (January 1, 1951): 15–18. doi:10.3181/00379727-76-18375.
Jukes, Thomas H. “Public Health Significance of Feeding Low Levels of Antibiotics to Animals.” In Advances in Applied Microbiology, edited by D. Perlman, Volume 16:1–30. Academic Press, 1973. http://www.sciencedirect.com/science/article/pii/S0065216408700212.
Roura, E, J Homedes, and K C Klasing. “Prevention of Immunologic Stress Contributes to the Growth-permitting Ability of Dietary Antibiotics in Chicks.” The Journal of Nutrition 122, no. 12 (December 1992): 2383–2390.
Gaskins, H. R., C. T. Collier, and D. B. Anderson. “Antibiotics as Growth Promotants:mode of Action.” Animal Biotechnology 13, no. 1 (2002): 29–42. doi:10.1081/ABIO-120005768.
Phillips, Ian, Mark Casewell, Tony Cox, Brad De Groot, Christian Friis, Ron Jones, Charles Nightingale, Rodney Preston, and John Waddell. “Does the Use of Antibiotics in Food Animals Pose a Risk to Human Health? A Critical Review of Published Data.” Journal of Antimicrobial Chemotherapy 53, no. 1 (January 1, 2004): 28–52. doi:10.1093/jac/dkg483.
Dibner, J. J., and J. D. Richards. “Antibiotic Growth Promoters in Agriculture: History and Mode of Action.” Poultry Science 84, no. 4 (January 1, 2005): 634–643.
Casey JA, Curriero FC, Cosgrove SE, Nachman KE, and Schwartz BS. “HIgh-density Livestock Operations, Crop Field Application of Manure, and Risk of Community-associated Methicillin-resistant Staphylococcus Aureus Infection in Pennsylvania.” JAMA Internal Medicine (September 16, 2013): -. doi:10.1001/jamainternmed.2013.10408.
Feighner, S. D., and M. P. Dashkevicz. “Subtherapeutic Levels of Antibiotics in Poultry Feeds and Their Effects on Weight Gain, Feed Efficiency, and Bacterial Cholyltaurine Hydrolase Activity.” Applied and Environmental Microbiology 53, no. 2 (February 1, 1987): 331–336.