Wednesday January 2, 2013, 9:42 am


Mother Jones
Can Antibiotics Make You Fat?
Factory animals are pumped full of antibiotics to make them gain weight. What does that mean for our waistlines?

By Tom Philpott | Wed Jan. 2, 2013 3:01 AM PST

Like hospital patients, US farm animals tend to be confined to tight spaces and dosed with antibiotics. But that's where the similarities end. Hospitals dole out antibiotics to save lives. On America's factory-scale meat farms, the goal is to fatten animals for their date at the slaughterhouse.

And it turns out that antibiotics help with the fattening process [1]. Back in the 1940s, scientists discovered that regular low doses of antibiotics increased "feed efficiency"—that is, they caused animals to put on more weight per pound of feed. No one understood why, but farmers seized on this unexpected benefit. By the 1980s, feed laced with small amounts of the drugs became de rigueur as US meat production shifted increasingly to factory farms. In 2009, an estimated 80 percent of the antibiotics sold [2] in the United States went to livestock.

This year, scientists may have finally figured out why small doses of antibiotics "promote growth," as the industry puts it: They make subtle changes to what's known as the "gut microbiome," the teeming universe populated by billions of microbes that live within the digestive tracts of animals. In recent research, the microbiome has been emerging as a key regulator of health [3], from immune-related disorders like allergies and asthma to the ability to fight off pathogens.

In an August study published in Nature [4], a team of New York University researchers subjected mice to regular low doses of antibiotics—just like cows, pigs, and chickens get on factory farms. The result: After seven weeks, the drugged mice had a different composition of microbiota in their guts than the control group—and they had gained 10 to 15 percent more fat mass.

Why? "Microbes in our gut are able to digest certain carbohydrates that we're not able to," says NYU researcher and study coauthor Ilseung Cho. Antibiotics seem to increase those bugs' ability to break down carbs—and ultimately convert them to body fat. As a result, the antibiotic-fed mice "actually extracted more energy from the same diet" as the control mice, he says. That's great if you're trying to fatten a giant barn full of hogs. But what about that two-legged species that's often exposed to antibiotics?

Interestingly, the NYU team has produced another recent paper [5] looking at just that question. They analyzed data from a UK study in the early '90s to see if they could find a correlation between antibiotic exposure and kids' weight. The study involved more than 11,000 kids, about a third of whom had been prescribed antibiotics to treat an infection before the age of six months. The results: The babies who had been exposed to antibiotics had a 22 percent higher chance of being overweight at age three than those who hadn't (though by age seven the effect had worn off).

The connection raises another obvious question: Are we being exposed to tiny levels of antibiotics through residues in the meat we eat—and are they altering our gut flora? It turns out that the Food and Drug Administration maintains tolerance limits for antibiotic residue levels, above which meat isn't supposed to be released to the public (PDF) [6]. But Keeve Nachman, who researches antibiotic use in the meat industry for the Johns Hopkins Center for a Livable Future [7], told me that the FDA sets these limits based solely on research financed and conducted by industry—and it refuses to release the complete data to the public or consider independent research.

"We may not understand the biological relevance of exposures through consuming meat at those levels," he says. Indeed, a recent European study [8] showed that tiny levels of antibiotics could have an effect on microorganisms. The researchers took some meat, subjected it to antibiotic residues near the US limit, and used a traditional technique to turn it into sausage, inoculating it with lactic-acid-producing bacteria. In normal sausage making, the lactic acid from the starter bacteria spreads through the meat and kills pathogens like E. coli. The researchers found, though, that the antibiotic traces were strong enough to impede the starter bacteria, while still letting the E. coli flourish. In other words, even at very low levels, antibiotics can blast "good" bacteria—and promote deadly germs.

Nachman stressed that we simply don't have sufficient information to tell whether the meat we eat is messing with our gut microbiome. But, he adds, "It's not an unreasonable suspicion." If that's not enough to churn your stomach, there's also the fact that drug-resistant bugs—which often emerge in antibiotic-dosed livestock on factory farms—are increasingly common: Remember the super-salmonella that caused Cargill to recall 36 million pounds of ground turkey [9] last year? Luckily for me, it's unlikely that drug-laced meat will mess with my gut. I think I've lost my appetite.
Source URL: http://www.motherjones.com/environment/2013/12/can-antibiotics-make-you-fat

Links:
[1] http://www.motherjones.com/tom-philpott/2012/04/fda-factory-farms-antibiotics
[2] http://www.livablefutureblog.com/2010/12/new-fda-numbers-reveal-food-animals-consume-lion%E2%80%99s-share-of-antibiotics
[3] http://www.nytimes.com/2012/06/19/science/studies-of-human-microbiome-yield-new-insights.html?pagewanted=all
[4] http://www.nature.com/nature/journal/v488/n7413/full/nature11400.html
[5] http://www.nature.com/ijo/journal/vaop/ncurrent/abs/ijo2012132a.html
[6] http://www.fsis.usda.gov/PDF/PHVt-Residue_Detection_Program.pdf
[7] http://www.jhsph.edu/research/centers-and-institutes/johns-hopkins-center-for-a-livable-future/
[8] http://mbio.asm.org/content/3/5/e00190-12.full
[9] http://www.motherjones.com/tom-philpott/2011/08/cargill-recall-turkey-salmonella

Wednesday January 2, 2013, 10:19 am
more research needs to be done on this, but as with everything, caution needs to be used

Wednesday January 2, 2013, 12:49 pm
Well, we aren't really ruminants.

Wednesday January 2, 2013, 2:05 pm
You cannot currently send a star to Nancy because you have done so within the last week.

Wednesday January 2, 2013, 3:30 pm

We use and abuse the antibiotics and in turn have created "super bugs" that are resistant to treatment. Consider that if the antibiotics assist in fattening the animals it just might have that affect on the human body.

Wednesday January 2, 2013, 4:20 pm
I don't know since I avoid anything that isn't natural.

Wednesday January 2, 2013, 4:51 pm
You cannot currently send a star to Kit because you have done so within the last week.
You cannot currently send a star to Michael because you have done so within the last week.

Wednesday January 2, 2013, 5:29 pm
Noted, THANKS. I am allergic to most antibiotics..............................

Wednesday January 2, 2013, 5:39 pm
You cannot currently send a star to Terry because you have done so within the last week.

Thursday January 3, 2013, 12:03 am
Noted, thanks.

Thursday January 3, 2013, 12:28 am
A month after I stopped eating meat I lost 10 pounds, with no effort and without even trying to.

Thursday January 3, 2013, 2:31 am
(This appeared to not go through, and failed to appear following a refresh, so I hope this won't double-post...)

Yes, of course antibiotics can make us gain weight - we're animals, too.

We are what we eat; they are what they eat; antibiotics and other drugs and toxins are passed in their meat and products; what we eat is what they consume also.

Factory farm animals are fed, essentially, garbage, GM foods and drugs.

The toxic industrial metals and chemicals accumulating up the food chain also affect us (and our pets - not to mention wildlife also developing cancers, auto-immune disorders, etc.) in many damaging ways, a number of them potentially also causing obesity as a symptom, particularly where endocrine disruptors are involved.

Whenever profiteering industry causes disease and dysfunction in a large area of the population, corporate-owned media begins to spew out industry 'science' blaming the victims 'lifestyles' for what independent science shows to be industrial ills - sometimes in advance of an anticipated epidemic because the damaging/deadly effect of some product, pollutant or process is already known, as with the projecting of large increases of diseases attributed to lifestyles present for a half century or more, with no indication given of why this would occur without some new factor having been introduced.

And we're having new factors added continuously - ranging from new petrochemicals and new biochemistry into our food supply to new nanoparticles being introduced into numerous products including cosmetics, food and food wrapping and poured into the environment via everything from laundry detergent to aerial spraying...

Thanks to JL A. for bringing attention to this - it's been going on for a very long time, and it's public awareness that will dispose of the victim blame excuse polluting/toxic industry has long used in avoiding liability for the ills it creates to increase profit and cut costs, thereby also creating much greater costs for society and the individuals affected.

If we can get accurate attribution, the causes can be recognised and, hopefully, sensibly dealt with at long last.

Sunday January 6, 2013, 3:07 pm
You cannot currently send a star to Giana because you have done so within the last week.
Thanks for all the additional analyses Dorothy! You cannot currently send a star to Dorothy because you have done so within the last week.