Patients with chronic hepatitis C virus (HCV) who drink more than 2.25 cups of regular coffee daily have milder liver fibrosis, finds a new study.
Researchers from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) found that the daily amount of caffeine intake (308 mg) had therapeutic effect on patients with chronic hepatitis C virus (HCV).
The study has been published in the January 2010 issue of Hepatology, a journal published by Wiley-Blackwell on behalf of the American Association for the Study of Liver Diseases.
Liver fibrosis or scaring of the liver is the second stage of liver disease and characterized by a degradation of liver function due to accumulated connective tissue.
"From data collected to date it remains unclear whether coffee itself, or caffeine provides the beneficial effect," said Apurva Modi, M.D. and lead author of the current study that focuses on caffeine intake and its impact on liver fibrosis.
From January 2006 to November 2008 all patients evaluated in the Liver Disease Branch of the National Institutes of Health were asked to complete a questionnaire to determine caffeine consumption. Questions were asked pertaining to all sources of caffeine including regular and diet soft drinks; regular and decaffeinated coffee; black, green, Chinese and herbal teas; cocoa and hot chocolate; caffeine-fortified drinks; chocolate candy; caffeine pills; and medications with caffeine.
Participants were asked about their frequency of caffeine consumption, which was quantified as never; 1-3 times per month; 1, 2-4, or 5-6 times per week; 1, 2-3, 4-5, and 6 or more times per day.
"Our data suggest that a beneficial effect requires caffeine consumption above a threshold of approximately 2 coffee-cup equivalents daily," noted Dr. Modi. The protective effects of consuming more than 308 mg of caffeine daily persisted after controlling for age, sex, race, liver disease, BMI and alcohol intake for all study participants.
Researchers further evaluated caffeine and coffee separately to determine the individual effect of each on fibrosis. Results showed that consumption of caffeinated soda, green or black tea was not associated with reduced liver fibrosis. However, a significant protective effect could have been missed due to small numbers, as 71pc of total caffeine consumed came from coffee.
Caffeinated coffee had the most pronounced effect on reduced liver fibrosis.