Find out what antibiotics do to your gut health.
Antibiotics are used to treat bacterial infections, and they do this by inhibiting or killing off bacteria in your body – including those in your gut. Unfortunately, this means that taking antibiotics can lead to some negative (and uncomfortable) side effects.
Your gut is made up of trillions of microbes, including good bacteria. These microbes play a big part in maintaining a healthy digestive system. When you take a course of antibiotics, the good bacteria often get wiped out along with the infection-causing bacteria, leaving your gut in a state of imbalance.
A study released in mBio, a journal published by the American Society for Microbiology found that eating antibiotics for a week caused microbial imbalances and shifts for up to a year afterwards. Hence, if you’ve ever experienced stomach discomfort after taking a dose of antibiotics, you’re not alone.
But just what happens in your gut, and does the age-old belief that eating antibiotics can affect your weight hold any, well, weight? Dr Gwee Kok Ann, medical director and consultant gastroenterologist at Gleneagles Hospital explains more below.
(Also read: 6 Important Facts You Must Know About Antibiotics)
How do antibiotics affect one’s gut?
Antibiotics may cause gut side effects by suppressing the naturally-occurring good bacteria (probiotics) found in the colon. As a result, more toxin-producing bacteria are produced – they stimulate contractions of the stomach and the intestines or directly irritate the lining of the oesophagus, stomach or intestine.
Do some antibiotics cause more stomach discomfort than others?
The penicillin class of antibiotics which includes ampicillin, amoxicillin and amoxicillin-clavulanic acid (e.g. Augmentin and Curam) can cause diarrhoea. Most of the time, this is temporary and mild. But some patients may develop a more serious condition known as pseudomembranous colitis. This is a condition where swelling or inflammation in the large intestines occurs due to an overgrowth of Clostridium difficile bacteria present in the gut. Other antibiotics such as piperacillin-tazobactam, clindamycin and moxifloxacin may also have similar side effects.
The macrolide class of antibiotics, which includes erythromycin and clarithromycin may also cause abdominal pain and diarrhoea because they stimulate contractions of the stomach and intestine. Metronidazole is another antibiotic that has a very high tendency to cause nausea and vomiting.
How can you reduce the side effects of taking antibiotics?
For a start, resist asking for antibiotics for common coughs, colds and flu-type infections – antibiotics are no use against viruses.
On the flip side, if you have to treat a condition with antibiotics, know that most side effects are harmless and temporary. It sometimes helps to take them with food to prevent any tummy discomfort. Some doctors may also recommend that you take a course of probiotics along with antibiotics.
(Also read: PSA: You Don’t Need Antibiotics If You Have The Flu)
What foods should you eat when taking antibiotics?
In theory, foods rich in probiotic bacteria could help to re-balance the natural gut bacteria population. These include yogurt or fermented milk drinks containing probiotic bacteria. (Psst, read this for a list of other probiotic-rich foods.)
What foods should you avoid?
Calcium has a tendency to bind chemicals that it comes into contact with, so foods containing calcium such as dairy products and soy milk may interfere with the absorption of antibiotics if these are taken together.
Citrus fruits should also be avoided. Some citrus fruits including grapefruits, limes, and pomelos contain a class of chemicals called furanocoumarins that inhibit an enzyme involved in processing many drugs including the antibiotic erythromycin. As a result, erythromycin could reach a level in the blood that may affect heart rhythm in a dangerous way.
Do antibiotics affect your weight?
The idea that antibiotics could affect a person’s body weight started from the observation that low doses of antibiotics served as growth promoters in livestock and farm animals. There is also research now that suggests the composition of gut bacteria in a person could influence body metabolism and thereby a person’s weight.
But research findings are still inconclusive. Chances are, any weight gain you experience comes from the food you eat or lack of exercise than from taking antibiotics.