Probiotics may be useful in weight loss, say UK researchers after finding the supplements influence fat absorption from the gut.
Studies in mice have shown that probiotics affect the way in which bile acids are metabolised, which in turn can change the amount of fat that the body is able to absorb.
The findings could lead to the development of new probiotic therapies designed to help treat gut abnormalities that have been linked to conditions such as obesity and diabetes.
Until now, the mechanism by which probiotics influence metabolism has been unknown.
For this latest study, researchers studied levels of metabolites in the liver, blood, urine and faeces of mice that had been engineered with human gut microbes to model the conditions found inside a human gut.
Some of mice were fed a probiotic containing Lactobacillus paracasei daily for two weeks, while a second group were fed a probiotic containing Lactobacillus rhamnosus. A third group served as controls and were given a saline drink.
The researchers found that the mice fed the probiotics had a higher gut content of bile acids, which are responsible for emulsifying fats in the upper gut, than control mice.
This was because the probiotic gut flora were unable to break down the bile acids.
In turn, this resulted in lower intestinal absorption of dietary lipids and a reduction of lipoprotein levels in plasma.
Lead researcher Professor Jeremy Nicholson, from the department of bimolecular medicine at Imperial College London, said that while some argue probiotics do not work, the study findings show probiotics can have a positive effect on metabolism.
'We are still trying to understand what the changes they bring about might mean, in terms of overall health, but we have established that introducing friendly bacteria can change the dynamics of the whole population of microbes in the gut.'
Dr Sunil Kochhar from the Nestle Research Centre in Switzerland added that the study results could lead to personalised nutrition.
Journal of Molecular Systems Biology Online 2008, live links at http://www.healthcarerepublic.com