Do Antibiotics Make Kids Fat?

More and more, research is showing us that childhood obesity is not only caused by genes, eating too much and exercising too little – but by several, poorly understood factors. One that’s been getting attention recently is the possible link between antibiotic use in early childhood and obesity later in life.

As the Director of Nationwide Children’s Center for Healthy Weight and Nutrition, I can tell you we do not fully understand what, if any, impact antibiotics have on obesity.

Nationwide Children’s is involved in a national study of 1.6 million kids to study the potential link between antibiotic use in the first two years of life and obesity in later childhood. It’s going to be about another year before we start getting some answers. Here’s what you need to know right now about antibiotics and obesity.

How could antibiotics impact weight gain? In the last five years, scientists have made compelling discoveries showing that there may be a connection between the amount and type of bacteria in our gut and weight gain. When antibiotics are prescribed for an illness, they can kill both the harmful and helpful bacteria in the body. It’s possible that when the levels of bacteria in the gut are disrupted, it sets off a chain reaction that alters the way fat tissue behaves.

How could a change in gut bacteria lead to childhood obesity? Babies are born with beneficial bacteria in their intestines that help digest food and keep illness-causing germs in check. This unique mix of bacteria is influenced by breast milk, formula, and even the way the baby was delivered! There is some evidence that when the balance of good bacteria is disrupted, other types of bacteria emerge.  These bacteria may increase calorie absorption, slow metabolism and cause very low levels of inflammation – all of which appear to trigger changes in fat cells that could lead to obesity.

Does the type of antibiotic used matter? Possibly. Our study will look to see if targeted types of antibiotics are less likely to influence weight gain versus broad-spectrum antibiotics which kill many different types of bacteria – not just the ones that cause illness. Our study is also researching if the timing of when a baby gets antibiotics (before or shortly after birth) makes a difference.

Should I talk to my pediatrician about reducing my child’s antibiotic use? No doubt your pediatrician is already very careful about not over-prescribing antibiotics.  You and your pediatricians should make the decision together about whether or not antibiotics will provide the most benefit to your child. It’s important to note that antibiotics don’t help most upper respiratory or ear infections.

What should I do if my child is taking antibiotics now to reduce their risk of obesity later? It’s important to emphasize that the link between childhood antibiotic use and obesity later in life is highly likely but not definite. That is the reason for the study. However, antibiotics can have side effects such as stomach upset and diarrhea; possibly because of gut bacteria changes during treatment. Some studies suggest giving your child probiotics or yogurt with active cultures can be helpful for restoring good bacteria in the gut after a course of antibiotics. There is no evidence that shows either have any effect on preventing possible long term weight gain.

While we are still trying to answer the question about antibiotics and obesity – there is one thing we know for sure: a diet high in refined sugars, fat and processed grains, large portions, sedentary behaviors coupled with a lack of exercise are huge risks for weight gain. Give your child healthy food choices, teach them how to eat well and encourage physical activity every day.  If you are interested in being a part of our study as a parent advisor please contact Rosanna Watowicz at 614-722-3598.Our parent advisors will participate in focus groups and help us make our study results meaningful to families.