People suffering from non-alcoholic fatty liver disease may benefit from regular exercise and replacing high-calorie beverages with decaffeinated, diet green tea, suggests new research.
The researchers found that a combination of green tea extract and exercise reduced the severity of obesity-related fatty liver disease by 75 per cent in mice fed a high-fat diet.
Although untested in human trials, the results suggest a potential health strategy.
"Combining the two might have health benefits for people, but we don't have the clinical data yet," said Joshua Lambert, Associate Professor of Food Science at The Pennsylvania State University in the US.
Non-alcoholic fatty liver disease is a significant global health problem that is expected to worsen, Lambert said.
Because of the high prevalence of risk factors such as obesity and Type-2 diabetes, fatty liver disease is forecast to afflict more than 100 million people by 2030. And there are currently no validated therapies for the disease.
In the study, mice fed a high-fat diet for 16 weeks that consumed green tea extract and exercised regularly by running on a wheel were found to have just a quarter of the lipid deposits in their livers compared to those seen in the livers of a control group of mice.
Mice that were treated with green tea extract alone or exercise alone had roughly half as much fat in their livers as the control group.
In addition to analyzing the liver tissues of mice in the study, which was published recently in the Journal of Nutritional Biochemistry, the researchers also measured the protein and fat content in their faeces.
They found that the mice that consumed green tea extract and exercised had higher fecal lipid and protein levels.
"By examining the livers of these mice after the study concluded and by screening their faeces during the research, we saw that the mice that consumed green tea extract and exercised actually were processing nutrients differently -- their bodies were handling food differently," Lambert said.
"We think the polyphenols in green tea interact with digestive enzymes secreted in the small intestine and partially inhibit the breakdown of carbohydrates, fat and protein in food," he added.
"So, if a mouse doesn't digest the fat in its diet, that fat and the calories associated with it pass through the mouse's digestive system, and a certain amount of it ends up coming out in its faeces," he said.