Diet-Caffeine consumption- less severe liver fibrosis
Caffeine Consumption Associated With Less Severe Liver
Fibrosis
Jan. 6, 2010 — Researchers from the
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
determined that patients with chronic hepatitis C virus (HCV) who consumed more than 308 mg of caffeine
daily had milder liver fibrosis. The daily amount of caffeine intake
found to be beneficial is equivalent to 2.25 cups of regular coffee. Other
sources of caffeine beyond coffee did not have the same therapeutic effect.
Details of this study are available
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. Past studies have
looked at modifiable behaviors, such as coffee consumption, that mitigate the
progression of liver disease. A number of studies have looked at the benefits of higher coffee intake
with results that include: lower
prevalence of chronic liver disease, reduced risk of hepatocellular carcinoma
(liver cancer), and lower
risk of death from cirrhosis complications. "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.
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% were male, 59%
Caucasian, 19% Black, 19% Asian, 3% Hispanic, and 68% had chronic HCV. Daily
consumption of caffeine from food and beverages raged from none to 1028 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%) followed by caffeinated
soda (13%), and black tea (4%). 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 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 71% of total
caffeine consumed came from coffee. Caffeinated coffee had the most pronounced
effect on reduced liver fibrosis. The authors suggest that further research is
needed to determine if the protective benefits of coffee/caffeine intake
plateau at amounts beyond the daily consumption threshold.
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