BETHESDA, Md.—Patients with chronic hepatitis C virus (HCV) who consume more than 2.25 cups of regular coffee daily have milder liver fibrosis, according to a new study published in the January 2010 issue of Hepatology.
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.
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 frequency questionnaire to determine caffeine consumption of 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.
The analysis included 177 participants who were undergoing liver biopsy with a mean age of 51 years and mean body mass index (BMI) of 27.5. Of those in the cohort 56 percent were male, 59 percent Caucasian, 19 percent black, 19 percent Asian, 3 percent Hispanic, and 68 percent had chronic HCV. Daily consumption of caffeine from food and beverages raged from 0 to 1,028 mg/day with an average of 195 mg/day, which is equivalent to 1.4 cups of coffee daily. Most caffeine consumed came from regular coffee (71 percent) followed by caffeinated soda (13 percent), and black tea (4 percent). Repeated administration of the questionnaire within a 6-month period displayed consistent responses suggesting caffeine intake does not significantly change over time.
Patients with an Ishak fibrosis score of less than 3 had a mean caffeine intake of 212 mg/day compared with 154 mg/day for those with more advanced fibrosis. The Ishak fibrosis score is the preferred system that measures degree of liver scarring with 0 representing no fibrosis through 6 indicating cirrhosis. For each 67 mg increase in caffeine consumption (about one half cup of coffee) there was a 14% decrease in the odds of advanced fibrosis for patients with HCV.
"Our data suggest that a beneficial effect requires caffeine consumption above a threshold of approximately two coffee-cup equivalents daily," the researchers wrote, adding 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.
