Can Antibiotics Cause Obesity?
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The obesity crisis isn’t just affecting adults—by age 2, 1 in 10 toddlers in the U.S. is considered obese. And it’s not just a diet of chicken nuggets and French fries that’s to blame. Researchers have flagged a handful of factors, including the mother’s pre-baby body mass index (BMI) and the child’s sleep duration and activity level, that might explain the growing problem of early childhood obesity.
But those are just the obvious explanations. There may also be subtle, unseen forces influences your child’s weight. A new study in the Journal of the American Medical Association published on Sept. 29 suggests that taking antibiotics before age 2 may predispose children to packing on the pounds.
The Children’s Hospital of Philadelphia researchers analyzed the medical records of more than 60,000 children who had seen a primary care doctor at least twice in their first 24 months, and then again after age 2. Of particular interest was how often the pediatric patients had received antibiotics from birth to age 23 months and how that related to their BMI later in childhood.
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In the study, 69 percent of the children had received antibiotics at some point in their first two years of life, and 14 percent had received the drugs even before they turned 6 months old. Why so many prescriptions? “For newborn babies, we are worried about infections — they can get seriously ill very quickly,” study author Dr. L. Charles Bailey told Yahoo Health. “So we use antibiotics a lot more aggressively than we would for older kids.” Plus, he added, both parents and pediatricians are eager to see children of any age recover, which may lead them to try anything that could potentially help.
For nearly two-thirds of the children that had received antibiotics, that meant taking “narrow-spectrum” antibiotics, such as penicillin and amoxicillin, which are the first route of treatment for childhood bacterial infections (think strep throat or an ear infection). And 41 percent of the children had received “broad-spectrum” antibiotics, the second line of treatment when narrow-spectrum options don’t kick the infection.
The difference between the drugs: “An antibiotic kills the bacteria causing the infection that you’re treating, but along the way, it will also kill some of the normal bacteria in your system,” explained Bailey. “A narrow-spectrum antibiotic kills a smaller number of bacteria. So you should take the narrowest-spectrum antibiotic that does that job you need it to do.” Broad-spectrum antibiotics are used only when children are seriously ill, so there’s usually little time for trial and error with these meds, particularly when the first-line antibiotic didn’t eliminate the infection.
So did the bacteria-fighting meds lower the kids’ defenses against flab?
The short answer: Yes. The more antibiotics a child took early in life, the more likely he or she was to be obese later on. (This was particularly true among children who had taken the drugs four or more times before age 2.) However, this held true only for overall or broad-spectrum antibiotic use; there was no such link between narrow-spectrum antibiotics and childhood obesity.
One explanation, say experts, is because broad-spectrum antibiotics more indiscriminately target bacteria, they may wreak more havoc on the good guys in your intestines. That may affect children’s future odds of weight gain.
Although the link between gut bacteria and body weight in humans is still preliminary, studies on mice have suggested that antibiotics change the types of bacteria that grow in the gut. The effect? “We worry that this changes the way you absorb calories from food, and then you may be more likely to be obese,” Bailey told Yahoo Health. “Digestion is a cooperative process — the bacteria do some of the work, and your body does some of the work. So it’s possible that when you have different kinds of bacteria in your intestines, you digest food in different ways.” Another theory: The bacteria in your digestive system may influence the kinds of foods you flock to.
It’s unclear whether the potential antibiotic-obesity connection extends to adults, although Bailey speculated that it might be most salient for young children. “We suspect [early childhood] is a particularly important period, because that’s when you’re starting to establish the bacteria that are going to be with you for a long time,” he said.
Related:Why America’s Children Are Overweight
So what should parents do to protect the future health of their little ones? They need to be proactive about asking why their child’s doctor is prescribing them and what the risks of not taking the drugs would be. “You want to ask yourself: Is this a case where [my child] needs antibiotics? If the answer is yes, use them. They’re wonderful drugs,” said Bailey. “But if the answer is ‘maybe’ or ‘just in case,’ then what we’re learning is that antibiotics don’t come without a cost.” In less clear-cut cases, especially when the suspected cause of the infection is viral, not bacterial, consider telling your pediatrician you’d like to hold off, he said.
If your child is in fact sick with a bacterial infection, accept the prescription, but ask your doctor about the type of antibiotic being offered: Is it narrow- or broad-spectrum?
"If we’re treating an ear infection and we’re not giving amoxicillin, why not? If the answer is, ‘We tried amoxicillin, and it didn’t work,’ then maybe it’s a good reason to use something else," said Bailey. "But if the answer is, ‘This broad-spectrum drug has once-a-day dosing, and you have to take amoxicillin twice a day,’ then maybe we want to pause and say, is that a good enough reason to use a broad-spectrum antibiotic?"
