People who are taking antibiotics may benefit from taking probiotics at the same time, a review of evidence shows.
Scientists at the organization Cochrane Collaboration say taking the supplements could prevent diarrhoea – a common side-effect of many antibiotics.
They looked specifically at cases of diarrhoea caused by the potentially dangerous Clostridium difficile bug.
Experts say probiotics could be a “pre-emptive strike” to ensure a healthy balance of bacteria in the gut.
Antibiotics can disturb the ecosystem of organisms normally present in the digestive system, allowing bacteria such as C. difficile to overwhelm the gut.
And people infected with the bug can suffer from diarrhoea, an inflamed and painful bowel or even death.
People who are taking antibiotics may benefit from taking probiotics at the same time
Researchers worldwide have been investigating whether probiotics – cocktails of micro-organisms – can keep gut bacteria in check by competing with more harmful bugs.
Scientists from the independent Cochrane Collaboration looked at data from 23 trials involving 4,213 patients who were on antibiotic treatment for a variety of reasons.
The researchers found 2% of patients given probiotics developed C. difficile-associated diarrhoea compared with 6% of patients who were taking placebos.
The authors suggest probiotics could be particularly useful when there are outbreaks of C. difficile.
Dr. Bradley Johnston, part of the Cochrane team, said: “Implementing the appropriate dose and strains of probiotics in hospitals could provide cost savings and improve quality of life.”
And the review showed that people taking probiotics had fewer unwanted side-effects than those on placebos, including stomach cramps, nausea and taste disturbances.
The authors say more work needs to be done to to pinpoint exactly which types of probiotics work best.
And though probiotics were seen to prevent diarrhoea associated with the bug, they note they did not prevent infections with C. difficile.
They suggest this property needs further investigation to help them understand more about how probiotics work.
According to US researchers, the rise of inflammatory bowel diseases could be down to our shifting diets causing a “boom in bad bacteria”.
Mouse experiments detailed in the journal Nature linked certain fats, bacteria in the gut and the onset of inflammatory diseases.
The researchers said the high-fat diet changed the way food was digested and encouraged harmful bacteria.
Microbiologists said modifying gut bacteria might treat the disease.
Inflammatory bowel diseases (IBDs) include Crohn’s and ulcerative colitis. When the gut becomes inflamed it can lead to abdominal pain and diarrhoea.
According to US researchers, the rise of inflammatory bowel diseases could be down to our shifting diets causing a "boom in bad bacteria"
The researchers at the University of Chicago said the incidence of the diseases was increasing rapidly.
They used genetically modified mice which were more likely to develop IBDs. One in three developed colitis when fed either low-fat diets or meals high in polyunsaturated fats. This jumped to nearly two in three in those fed a diet high in saturated milk fats, which are in many processed foods.
These saturated fats are hard for the body to digest and it responds by pumping more bile into the gut. This changes the gut environment and leads to a change in the bacteria growing there, the researchers said.
One bacterium in particular, Bilophila wadsworthia, was identified. It thrives in the extra bile produced to break down the fats. It went from being incredibly rare to nearly 6% of all bacteria in the gut in the high-fat diet.
Prof. Eugene Chang, of the University of Chicago, said: “Unfortunately, these can be harmful bacteria. Presented with a rich source of sulphur, they bloom, and when they do, they are capable of activating the immune system of genetically prone individuals.”
However, he said this could lead to possible treatments as the gut bacteria could be “reshaped” without “significantly affecting the lifestyles of individuals who are genetically prone to these diseases”.