Scientists say they have hard evidence foods containing "friendly bacteria" do have a tangible effect on the body.
The journal Molecular Systems Biology reports that mice fed probiotic drinks had different levels of key chemicals in their blood and urine.
The Imperial College London research - which was part-funded by food giant Nestle - also suggested they could change fat digestion. But dieticians say they work only for relatively small numbers of people. The science of probiotics has been controversial, with suggestions that even the billions of bacteria in a pot of yoghurt could not possibly influence the trillions already found in our guts. However, the mouse research does offer some evidence of an measurable effect, say the researchers.
They fed some mice a normal diet, but added a drink containing "friendly bacteria" to the diet of others.
Screening the blood, urine, faeces and livers of the mice revealed that levels of several key chemicals related to important processes in the body were altered in the probiotic-treated animals.
Source - BBC