Do Probiotics Really Protect Your Gut When Taking Antibiotics? Experts Explain

If you’ve ever taken antibiotics, you might’ve noticed your digestive system took a bit of a hit. 

On a very simple level, the medication targets bacteria in the body to kill off the bad stuff – unfortunately it can also get rid of the good stuff, too.

Research suggests antibiotic-associated diarrhoea can occur in 5-30% of people either during the early stages of them taking antibiotics, or up to two months after. 

These loose stools are one of the “clearest signs” that antibiotics are impacting your gut health, according to Dr Megan Rossi, a gut health scientist at King’s College London and founder of Smart Strains. 

“The extent to which antibiotics affect the gut depends on several factors,” she told HuffPost UK.

“Firstly, the type of antibiotic matters. Some antibiotics are narrow-spectrum, meaning they target specific bacteria, while others are broad-spectrum and affect a much wider range of bacteria, including many of the beneficial microbes that live in our gut.

“Dose is another important factor, and repeated or prolonged courses of antibiotics can also have a greater cumulative impact on the gut microbiome.”

Can you protect your gut health when you’re on antibiotics?

Dr Michael Passarella, a gastroenterologist at The University of Alabama Birmingham St. Vincent’s Hospital, suggested it’s “difficult to truly ‘protect’ the microbiome” while taking antibiotics.

That said, certain probiotics, “especially Lactobacillus, Bifidobacterium and Saccharomyces boulardii, have shown to reduce the risk of antibiotic-associated diarrhoea,” Dr Passarella previously said. “They are safe to use, but the long-term benefits are uncertain.”

Dr Rossi points to recommendations from the The World Gastroenterology Organisation that people on antibiotics should take 10 billion CFU of the specific bacterial strain Lactobacillus rhamnosus GG (LGG), twice daily, alongside antibiotic treatment to help reduce the risk of antibiotic-associated diarrhoea.

“This is the exact formulation used in Smart Strains [Dr Rossi’s own brand] for When You’re on Antibiotics,“ she added.

“The formulation has been shown to reduce antibiotic-associated diarrhoea by around 70% compared with placebo in both adults and children in randomised controlled trials.”

Probiotics might also help, but Dr Rossi notes that not all probiotics are the same. “Each different type of bacteria, known scientifically as a strain, has different effects, so the evidence for one strain cannot be applied to another,” she explained.

“Just as I wouldn’t recommend an iron supplement to treat a vitamin D deficiency, I wouldn’t recommend a generic probiotic when the evidence supports a specific strain.”

If your probiotic contains the LGG strain, that is a good sign. Dr Rossi notes the World Gastroenterology Organisation recommends taking this type of strain during your antibiotic course, rather than waiting until it’s finished.

“The recommended dose is 10 billion CFU twice daily, ideally taken a couple of hours away from the antibiotic dose. I also recommend continuing it for at least one week after finishing the antibiotic course to help support recovery of the gut microbiome,” she added.

Dr Passarella also suggested that you don’t need to go for the expensive brands as “some of the commonly found over-the-counter options are just as effective”. 

“A high CFU count isn’t necessarily better. The specific strain matters more than the number of bacteria,” he added.

Diet is also a big consideration during this time. Dr Passarella noted “fibre basically acts as a prebiotic”.

“If probiotics are the good bacteria, prebiotics are the food they need to thrive,” he explained, adding that it’s important to eat fruit, vegetables and other fibre-rich foods while taking antibiotics.

Some healthcare providers recommend eating more yoghurt with live cultures while taking antibiotics (providing you’re not sensitive to it).

Yoghurt contains Lactobacillus acidophilus, according to Dr Ravinder Machra, of West Tennessee Medical Group Primary Care. This can help “reup your bacterial balance while you’re taking an antibiotic”, she said.

Fermented foods such as kimchi and sauerkraut may also help.