Study finds caffeine in sources other than coffee does not have similar effect
Good news to start the new year for the leagions of coffee drinkers. Another study that finds coffee may have positive health benefits. 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 apparently did not have the same therapeutic effect. The study is published in the journal Hepatology,
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:
1: Lower prevalence of chronic liver disease,
2: Reduced risk of hepatocellular carcinoma (liver cancer),
3: 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.
For the study, 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 study 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.
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.