Coffee Could Stall Liver Disease Progression
Drinking three or more cups of coffee daily lowers the risk of liver disease progression for patients with chronic hepatitis C, researchers say.
Those who so indulged had a 53% decreased risk of disease progression, compared with patients who didn't drink coffee, Neal D. Freedman, MD, of the National Cancer Institute, and colleagues reported in the November issue of Hepatology.
"Although we cannot rule out a possible role for other factors that go along with drinking coffee, results from out study suggest that patients with high coffee intake had a lower risk of disease progression," Freedman said in a statement.
Black tea or green tea, however, had no effect on liver disease, the investigators reported.
Previous research suggested that coffee may hold benefit for liver patients. Coffee consumption has been inversely associated with liver enzyme concentrations, including alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltransferase.
Lab studies also suggest that several components of coffee -- including caffeine, diterpenes, and polyphenols -- may have beneficial effects on the liver.
To assess this relationship, the researchers looked at data from the Hepatitis C Antiviral Long-Term Treatment against Cirrhosis (HALT-C) trial.
Baseline coffee and tea intake were assessed in 766 participants who had hepatitis C-related bridging fibrosis or cirrhosis and failed to achieve a sustained virological response to peginterferon-plus-ribavirin.
Patients were followed for 3.8 years for clinical outcomes -- a total of 230 had outcomes.
The researchers found an inverse association between coffee intake and liver disease progression.
At baseline, higher coffee consumption was associated with less severe steatosis, lower serum aspartate aminotransferase/alanine aminotransferase ratio, alpha-fetoprotein, insulin, and homeostatic model assessment (HOMA2) score, and higher albumin (P<0.05).
Outcome rates declined with increasing coffee intake (P=0.0011):
11.1 per 100 person-years for no coffee intake
12.1 for less than one cup per day
8.2 for one or two cups a day
6.3 for three or more cups a day
Compared with those who didn't drink coffee, those who drank less than one cup per day had a 1.11-fold increased risk of worsening disease (95% CI 0.76 to 1.61), but there was a protective effect for those who drank one to two cups per day (OR 0.70, 95% CI 0.48 to 1.02).
The protective effect was greatest for those who drank three or more cups per day (OR 0.47, 95% CI 0.27 to 0.85, P=0.0003).
Tea intake was not associated with any outcomes, the researchers said.
They noted that adjustment for lifetime or current alcohol consumption or cigarette use did not affect risk estimates for the relationship.
"Coffee intake is not generally considered to be part of a healthy lifestyle," they said. "Nevertheless, as in all observational analyses, observed associations in this study could be attributable to unmeasured or poorly measured confounders."
Still, the investigators mentioned some mechanisms by which coffee may inhibit disease progression. For example, they said it may modulate insulin sensitivity, as one ingredient -- chlorogenic acid -- has been shown to inhibit activity of glucose-6-phosphatase, an important regulator of blood glucose levels.
Coffee may also act by reducing inflammation, as the inflammatory response to liver injury is thought to cause fibrosis and cirrhosis.
Or, the researchers said, coffee may act by reducing oxidative stress, which may play a role in hepatic damage and disease progression.
They noted that the study may have been limited by a lack of information on decaffeinated coffee consumption, soft drink consumption, and coffee brewing methods. Also, it was limited by self-reported data on coffee consumption, and may not be generalizable to healthy populations.
The researchers reported no conflicts of interest.
Primary source: Hepatology
Freedman ND, et al "Coffee intake is associated with lower rates of liver disease progression in chronic hepatitis C" Hepatology 2009; DOI: 10.1002/hep.23162.