Researchers investigated whether modest alcohol consumption can reduce liver fibrosis and cell damage in patients with non-alcoholic fatty liver disease.
The liver is a large organ located in the right upper abdomen just under the rib cage. It has many important functions including filtering the nutrients in blood coming from the digestive tract, storing and releasing energy, and producing bile fluid and clotting factors. A healthy liver stores some fat, but if fat in the liver is more than 5-10% of its weight, this is known as “fatty liver disease”. This can be caused by high alcohol intake, called alcoholic fatty liver disease (AFLD), but often it is unrelated to alcohol, called non-alcoholic fatty liver disease (NAFLD). The cause of NAFLD is unclear. However, it may run in families or be linked to other conditions such as obesity or diabetes.
The liver damage seen in NAFLD may be reversed by healthy lifestyle changes, but if unhealthy conditions persist NAFLD can progress to “non-alcoholic steatohepatitis” (NASH). As liver cells become damaged this leads to scarring or liver fibrosis and eventually, if damage continues, to liver cirrhosis. Initially, patients with NAFLD may not notice any symptoms, but if liver damage progresses they may experience fatigue, weight loss, and upper abdominal pain.
Can Light Alcohol Consumption Protect the Liver in NAFLD?
There is no specific treatment for NAFLD, but patients are advised to avoid factors which may further damage the liver. They should follow a healthy lifestyle, maintain a normal body weight, and make sure that any co-existing medical conditions such as diabetes are well-controlled. Whilst patients with AFLD are advised to stop drinking, some studies have suggested that moderate alcohol consumption may have a beneficial effect on patients with NAFLD. Researchers in Japan investigated the relationship between alcohol intake and the cell changes seen in patients with NAFLD. They recently reported their findings in the journal PLoS ONE.
Study participants were recruited from amongst patients diagnosed with NAFLD at the Kanazawa University Hospital between 1998 and 2013. The 178 patients in the study group were divided into two groups based on their self-reported alcohol intake; non-drinkers (101 patients) and light alcohol consumption of up to 20 g ethanol per day (77 patients). The patients had blood samples and liver biopsy samples taken for analysis.
Some of the microscopic cellular features of liver damage, known as “ballooning” and “liver fibrosis”, were significantly lower in the light alcohol consumption group compared to the non-drinkers group. A more detailed analysis of gene expression in a subgroup of patients showed that immune system pathways which may lead to inflammatory responses were much reduced in the light alcohol consumption group compared to the non-drinking group.
The researchers concluded that light alcohol consumption might reduce gene expression levels in the immune response and so reduce liver cell damage and liver fibrosis. They suggest that modest alcohol consumption, in addition to healthy lifestyle changes, may have a role in preventing the progression of NAFLD to NASH.
Written by Julie McShane, Medical Writer
Reference: Yamada K, Mizukoshi E, Seike T, et al. Light alcohol consumption has the potential to suppress hepatocellular injury and liver fibrosis in non-alcoholic fatty liver disease. PLOS ONE Jan 17, 2018. Doi: 10.1371/journal.pone.0191026