Liver cirrhosis is a major, growing, and largely preventable cause of death worldwide, accounting for more than 1 million deaths globally per year.2 The risk of death from liver cirrhosis differs markedly between countries, driven primarily by alcohol consumption, the type and quality of alcohol consumed, and the presence of viral hepatitis B and C infections. Gut microbiota have been implicated in the pathogenesis and progression of cirrhosis,3,4 and a progressive decrease in microbial diversity is observed in healthy individuals, individuals with compensated cirrhosis, and those with decompensated disease.
‘A diet that is Mediterranean style is associated with greater gut microbial diversity and a lower risk of hospitalization in patients with liver cirrhosis.’
'Diet is a major determinant of gut microbial composition, but there is very little information currently linking diet, microbial diversity and clinical outcomes in patients with cirrhosis', said Dr Jasmohan Bajaj from Virginia Commonwealth University and McGuire VA Medical Center in Richmond, USA, and lead author of the study. 'Our hypothesis for this study was that diet and the severity of cirrhosis might interact to determine microbiota composition and, ultimately, clinical outcomes in patients with liver cirrhosis'.
The study presented by Dr Bajaj recruited three groups of individuals in the USA (n=157) and Turkey (n=139): healthy controls, outpatients with compensated cirrhosis, and outpatients with decompensated cirrhosis. All individuals underwent dietary and stool microbiota analysis and those with liver cirrhosis were followed for at least 90 days to capture data on non-elective hospitalizations.1 The US population tended to follow a Western diet with a relatively low consumption of fermented foods (yoghurt, ayran, curds) and a high consumption of coffee and carbonated drinks, while the Turkish cohort consumed a Mediterranean-style diet that was rich in fermented foods and vegetables.1
Stool sample analysis revealed that the entire Turkish cohort had a significantly greater diversity in their gut microbiota than the US cohort and that there was no difference in diversity between healthy controls and those with liver cirrhosis in Turkey. In contrast, in the US cohort, diversity was highest in the control group and lowest amongst those with decompensated cirrhosis. Coffee, tea, vegetables, chocolate, and fermented milk intake predicted a higher diversity, while the Model for End-stage Liver Disease (MELD) score, lactulose use and carbonated drink consumption predicted a lower microbial diversity. There was a significantly higher number of all-cause and liver-related hospitalizations during the 90-day follow-up in the US cohort compared with the Turkish cohort (p=0.016 for all-cause; p=0.02 for liver-related).1
'This study demonstrates that patients with cirrhosis have gut microbiota profiles that are highly responsive to dietary factors, and it is the first study to confirm a link between diet, microbial diversity and clinical outcomes in liver cirrhosis', said Dr Bajaj. 'Additional studies are now required to evaluate whether dietary modification might improve both microbial diversity and clinical outcomes in these patients'.
'Whether or not dietary changes can be used as a non-pharmacological tool to improve patients' outcomes in cirrhosis remains to be tested by specifically designed studies that take into account possible confounders. Nonetheless, this study adds to the existing evidence indicating a robust, pleiotropic beneficial effect of following a "Mediterranean-style diet" on human health', said Prof. Annalisa Berzigotti from the University of Bern, Switzerland, and EASL Governing Board Member.