Latest scientific news 01 July 2014

Can moderate consumption of alcoholic beverages protect against non-alcoholic fatty liver disease?

Moderate intake of alcoholic beverages seems to be associated with a significant protective effect on developing non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease and its prevalence has been continuously rising over the past decade in most parts of the industrialised world. NAFLD occurs when the liver has trouble breaking down fats, causing fat to build up in the liver tissue. It is defined as the fattening of the liver cells (with > 5,5% of liver cells being fatty), not due to the excessive use of alcoholic beverages (defined as > 20 grams of alcohol per day for women and > 30 grams for men).

The clinical course of NAFLD varies widely. The wide range of diseases and conditions linked to NAFLD is so diverse that it is difficult to pinpoint any one cause.

Patients with NAFLD may eventually develop non-alcoholic steatohepatitis (NASH), where the fat causes inflammation in the liver. This can impair the liver’s ability to function and lead to scarring of the liver (cirrhosis). With time, scarring can become so severe that the liver no longer functions adequately (liver failure). NASH is the third most important indication for liver transplantation in the US and the only indication for which the incidence is increasing. In addition, recent data have shown that NAFLD also is the most common cause of liver cancer, which can occur even without cirrhosis.

NAFLD cannot only cause liver problems but it is now also recognised as the hepatic manifestation of a metabolic derangement of the body, with insulin resistance as the common patho-physiological mechanism. Thus, patients with NAFLD are at increased risk of metabolic syndrome, type 2 diabetes mellitus, cardiovascular disease (CVD) and several forms of cancer.

Once diagnosed with NAFLD, avoiding excessive consumption of alcoholic beverages is usually recommended to the patients. Since diabetes and cardiovascular disease are major causes of death in individuals with NAFLD, and moderate alcohol consumption on the other hand, with its many beneficial effects is inversely related to type 2 diabetes and CVD, it seems very important to examine the effects of moderate intake of alcoholic beverages on the risk of developing NAFLD as well as the physiological consequence in patients with NAFLD.

A meta-analysis of epidemiological studies investigating the association between alcohol consumption and NAFLD risk was carried out by a team of Argentinean researchers from the University of Buenos Aires (Argentina). Eight studies with 43,175 adults (30,791 non-drinkers and 12,384 modest drinkers (defined as < 40 grams alcohol per day) were included. The analysis showed that moderate consumption of alcoholic beverages was associated with a significant protective effect, i.e. a 31% lower risk of having NAFLD. Even more remarkable, moderate alcohol consumption was associated with a 50% lower risk of developing an advanced disease stage (1).

Recently, the first study assessed the association between the intake of alcoholic beverages and cardiovascular diseases in NAFLD. Carotid plaques represent a good clinical model of early atherosclerosis. They can be identified by carotid ultrasound which is simple and non-invasive, with no risk of radiation exposure and is an established method indicating increased cardiovascular risk. In addition, carotid artery stenosis (CAS) on carotid ultrasound is a marker of increased risk for transient ischemic attacks and strokes, and correlates well with coronary artery disease. Thus, both carotid plaques and CAS can be used as surrogate markers for assessing the risk of cardiovascular disease.

For this purpose, South Korean scientists carried out a cross-sectional study with 10,581 consecutive male participants aged 30 years or older undergoing abdominal ultrasonography and carotid artery ultrasonography. Secondary causes for fat accumulation or other causes of chronic liver disease were excluded. A total of 2280 men were diagnosed with fatty liver. Among them, 1797 were moderate drinkers of alcoholic beverages (less than 20g of alcohol per day). The statistical analysis (adjusted for age, smoking and metabolic syndrome) showed that moderate alcohol consumption was inversely associated with carotid plaques (odds ratio 0.74) and carotid artery stenosis in men with NAFLD (OR: 0.62). The researchers concluded that prospective long-term follow-up studies that compare the effects of various alcohol doses on the cardiovascular risk among populations under various liver conditions (such as individuals with or without fatty liver) are needed to advance the understanding about the link between alcohol, liver and cardiovascular diseases.

1. Sookoian S, Castaño GO, Pirola CJ. Modest alcohol consumption decreases the risk of non-alcoholic fatty liver disease: a meta-analysis of 43 175 individuals. 

Gut. 2014;63:530-2.

 For more information about this article, read the scientific abstract here.


2. Sinn DH, Gwak GY, Cho J, et al. Modest alcohol consumption and carotid plaques or carotid artery stenosis in men with non-alcoholic fatty liver disease.

Atherosclerosis. 2014;234:270-5.

For more information about this article, read the scientific abstract here.