coffee was associated with lower liver stiffness – a non-invasive measure used
to estimate liver fibrosis – in people with hepatitis B, hepatitis C and
non-alcoholic fatty liver disease (NAFLD), researchers reported at the 2015
AASLD Liver Meeting last week in San Francisco, USA. The study also showed a
trend toward less liver fat build-up in people with NAFLD.
Over years or decades, chronic hepatitis B
virus (HBV) or hepatitis C virus (HCV) infection can lead to serious liver
disease including cirrhosis (scarring), hepatocellular carcinoma (a type of
liver cancer) and liver failure necessitating a transplant. NAFLD – fat in the
liver not related to alcohol use – can lead to the same outcomes. As HBV
vaccination and effective new treatments for hepatitis C reduce liver disease
due to viral hepatitis, NAFLD is expected to become a major indication for
liver transplantation, given rising rates of obesity.
Alexander Hodge of Monash Medical Centre in
Melbourne, Australia, and colleagues conducted a retrospective, cross-sectional study to see whether coffee
consumption leads to improvements in non-invasive markers of liver fibrosis and
steatosis (fat accumulation).
A non-invasive test, used instead of a biopsy, to measure the stiffness
or elasticity of the liver using an ultrasound probe.
Abnormal fat deposits in the liver.
In prior studies, coffee consumption has been linked to a wide range of
health benefits including reduced risk of type 2 diabetes, metabolic syndrome
and several types of cancer, the researchers noted as background. It may have a
particularly beneficial effect on the liver, being associated with lower liver
enzyme levels and reduced cirrhosis and liver cancer. It is not yet known
whether these benefits are related to caffeine or other components of coffee
such as antioxidants or other phytochemicals. Some studies suggest caffeine and
other chemicals in coffee may dampen inflammation and reduce collagen
In this study, liver health was assessed using transient elastography or
FibroScan. Although liver biopsy has
traditionally been considered the 'gold standard' for determining the extent of
liver injury, clinicians are increasingly using less expensive non-invasive
Transient elastography uses shear waves to assess liver elasticity or 'stiffness'.
Higher liver stiffness scores (expressed in kiloPascals or kPa) indicate more extensive
liver damage. A score below 6-7 kPa suggests absent or mild fibrosis (stage
F0-F1) while a score above 13 to 14 kPa suggests cirrhosis (stage F4) in people
with viral hepatitis.
Another transient elastography measure, the
controlled attenuation parameter or CAP (expressed in decibels per meter
or dB/m), is used to assess liver steatosis. Fat blocks propagation of
ultrasound waves, so greater attenuation suggests more steatosis. Scores
from 100 to 400, with a score above 250 suggesting significant
The researchers collected data on self-reported coffee and alcohol
consumption – as well as the type of coffee (instant, espresso, filtered or
boiled) – among all patients with hepatitis B, hepatitis C or NAFLD undergoing
transient elastometry at their hospital clinic between May 2012 and November
2013. They also obtained information about demographic characteristics, weight
and body mass index (BMI), smoking and alanine aminotransferase (ALT) liver
Over 18 months, the researchers evaluated 1130 people, including 529
(47%) with hepatitis B, 434 (38%) with hepatitis C and 167 (15%) with NAFLD.
Overall, 57% were men, the average age was 48 years and a quarter were smokers.
The average BMI was 25.7 kg/m2 and the mean ALT level was 39 IU/L
among people with available measurements.
Most participants reported that they consumed some coffee, with a median
of one cup per day but ranging up to 20 cups daily; 72% reported drinking
instant coffee and 24% drank espresso, with only a small number (1 to 2%) drinking
filtered, boiled or decaf coffee. Average daily alcohol consumption was about 5
The median liver stiffness score across all participants was 6.1 kPa,
suggesting absent to mild fibrosis. However, people with HBV had lower scores
than those with HCV or NAFLD (median 5.3, 7.1 and 7.4, respectively).
Among people with available controlled
attenuation parameter data, the overall
mean CAP score was 214 dB/m, rising above the steatosis threshold only for
those with NAFLD (mean 201, 210 and 258, respectively).
People with hepatitis C who drank two or more cups of coffee daily had a
13% reduction in liver stiffness after taking
into account confounding factors including age, sex, weight, alcohol
consumption and smoking – a significant association. People with hepatitis B
who drank four or more cups of coffee had a significant 18% reduction in liver
stiffness in an adjusted analysis including ALT. There were no significant
associations between coffee consumption and CAP scores among people with
hepatitis B or C.
Among people with NAFLD, those who drank four or more cups of coffee
daily had a 24% decrease in liver stiffness in an adjusted analysis. Greater
coffee consumption showed a trend towards an association with lower CAP scores
in people with NAFLD, but this fell short of statistical significance. Coffee
consumption had no effect on CAP in people with hepatitis B or C.
Based on these findings, the researchers concluded that "coffee
consumption is associated with less liver stiffness in patients with NAFLD, HCV
and HBV, [and a] trend to less hepatic steatosis in [patients with]
These findings, they said, "add to the growing body of evidence
suggesting coffee may be a beneficial supplement in some liver diseases."