The researchers said both butyrate-producing probiotics and sodium butyrate (SoB) supplements had been tipped for their possible protective effects against liver damage.
SoB is a naturally occurring short-chain fatty acid produced in the body mainly by intestinal bacteria and found in various foods like cheese and butter.
Yet whether taking an oral supplement of SoB had a protective effect against Western-style diet-induced NASH and what molecular mechanisms were behind this was yet to be determined before this study.
The researchers from the Institute of Nutritional Sciences at the Friedrich-Schiller-University Jena in Germany fed eight-week old mice either a liquid control diet or a western-style diet fortified with fructose, fat and cholesterol and supplemented with 0.6 g per kg body weight of SoB.
Non-alcoholic fatty liver disease (NAFLD) refers to liver diseases involving hepatic steatosis – or fatty liver – that are not caused by excessive alcohol intake. NAFLD includes various liver diseases from simple fatty change to non-alcoholic steatohepatitis (NASH).
NASH causes scarring of the liver - liver cirrhosis – which in turn causes loss of function due to long-term damage. This may also lead to hepatocellular carcinoma – the most common type of liver cancer.
After six weeks, they examined the mice's liver tissue for markers of liver damage, inflammation, the immune system’s toll-like receptor (TLR)-4 signalling, the cell damage process lipid peroxidation and glucose as well as lipid metabolism.
SoB supplementation had no effects on the body weight gain or liver weight of the experiment mice, but liver steatosis and hepatic inflammation were significantly decreased compared to mice fed the western-style diet alone.
"Indeed, these mice displayed less macrovesicular fat accumulation and almost no inflammatory foci in their livers," they wrote in the British Journal of Nutrition.
They said the protective effect of sodium butyrate was linked to the induction of the immune system's toll-like receptor 4 signalling cascade, lipid peroxidation and fatty acid synthase in the liver.
They called for further research on SoB and liver disease in humans.
Growing public health concern
A 2013 review of 260 epidemiological studies published in Europe over the previous five years suggested non-alcoholic fatty liver disease (NAFLD) was now the most frequent liver disease in Europe.
“Available data suggest the prevalence rate of NAFLD is 2-44% in the general European population (including obese children) and 42.6-69.5% in people with type 2 diabetes,” the review said at the time.
Despite this pressing public health backdrop, the researchers behind this latest paper said: “Up to now, life-style- or pharmaceutical-based interventions aiming to prevent the development but even more so the progression of NAFLD are still limited.”
In July the consultancy firm Naturalpha a clinical trial platform dedicated to the relatively unexplored area of NAFLD.
Eric Chappuis, the firm’s director of consulting, told us at the time: “Our feeling is that this topic, which is poorly addressed to date by the nutrition and nutraceutical industry, will become a major topic in the coming years. However the lack of understanding of the epidemiological burden of these conditions as well as sometimes short-term vision of the nutra industry has not yet led to concrete development.”
Source: British Journal of Nutrition
Published online ahead of print, doi:10.1017/S0007114515003621
“Supplementation of sodium butyrate protects mice from the development of non-alcoholic steatohepatitis (NASH)”
Authors: C. Jun Jin, C. Sellmann, A. Janina Engstler, D. Ziegenhardt and I. Bergheim