The study – presented to experts at the recent American Society for Biochemistry and Molecular Biology meeting – explained that consumption of soy protein from sources including tofu and yoghurts reduces the build-up of fats in the liver by partially restoring the functions in an important cellular signaling pathway.
Led by Dr Hong Chen, an assistant professor of food science and human nutrition at the University of Illinois, the research team reported that soy protein could reduce the amassing of fats in the liver by up to 20% in obese rats.
"When fat accumulates in an organ that's not supposed to store fat — like the liver, that organ's vital function can be dangerously compromised," said Chen, who noted that obesity is a ‘key risk factor’ for fatty liver disease.
She added that fat is metabolised in the liver and then transported away for storage in other organs, however in obese people such transport out of the liver can slow down to the point where fats and triglycerides build up.
Consumption of soy proteins seems to alleviate this backlog by restoring transport out of the liver, said Chen.
"In many obese persons, there's a sort of traffic problem, and when more fat can make its way out of the liver, there is less pressure on that organ," she explained.
The US based researchers compared fat accumulation in the livers of lean and obese rats.
The team assigned groups of obese and lean rats to receive either a diet containing casein, a milk-based protein, or a diet containing soy protein, for 17 weeks after weaning.
Chen revealed that while diet had no effect on the liver profiles of lean animals – obese rats that were fed soy showed a 20% reduction in triglycerides and overall fat accumulation in the liver.
Furthermore, the research group discovered that soy protein isolate partially restored the Wnt/beta-catenin signalling pathway – which plays an important role in fat metabolism and in the transport of fat out of the liver.
The lead researcher said the finding has led her to believe that soy protein could be used to alleviate the symptoms of fatty liver disease by reducing the ‘stress’ put on fatty livers.