Exercise and dietary changes may affect the liver via gut microbes
Genetic susceptibility to fatty liver disease may partly explain the development and individual progression of the disease. The risk of fat accumulating in liver cells is increased, for example, by the PNPLA3 gene variant, which as many as 40% of Finns have inherited from at least one parent.
In recent years, it has been observed that fatty liver disease also involves changes in the gut microbiota. Funded by the EU, the BestTreat research consortium is currently investigating how the microbial composition of the gut affects the prognosis of the disease, and whether it could also be treated by promoting a normal composition and function of the gut microbiota. As a member of this European consortium, Professor Schwab's research group seeks to find out how physical exercise affects the microbial composition of the gut and the accumulation of fat in the liver.
“The idea is to examine whether physical exercise changes the microbiota so that the accumulation of fat in the liver decreases.”
People diagnosed with non-alcoholic fatty liver disease participated in a 12-week exercise programme. The programme included one weekly exercise session of the participants’ own choice, such as walking, jogging or swimming, and two supervised exercise sessions on a bicycle ergometer, with resistance increasing in tandem with fitness.
“Three months should be enough to achieve clinically relevant results. However, these findings are yet to be published, because they will be combined with data from a similar intervention in the Netherlands next winter,” Professor Schwab says.
Professor Schwab’s research group is currently conducting another study to investigate the association between dietary fat quality and the accumulation of fat in the liver. Half of the study participants have inherited the PNPLA3 risk variant from both parents, while the other half are not variant carriers.
“Other studies have shown us that by making lifestyle changes, it is possible to silence genes that make people susceptible to diseases. Now we will see if this gene can be silenced by replacing saturated fats with unsaturated ones, as encouraged in nutrition recommendations.”
The effects of dietary changes will be examined not only on the participants’ liver tissue, liver enzymes and glucose tolerance, but also on their gut microbiota.
“The effect of the diet on the gut microbiota, and further on the accumulation of fat in the liver, is not yet fully understood, although a link between them has been observed.”