Liver function

Overview

• Two meta-analyses conclude that the available prospective cohort and case-control studies all show an inverse association between moderate coffee consumption and liver cancer, suggesting that an increased consumption of coffee may reduce the risk of liver cancer.
• The results of the prospective cohort studies, in particular, are indicative of a dose-response relationship. Two extra cups of coffee per day are associated with a 43% reduced risk of liver cancer, amongst populations who typically consume anything from 1 to over 5 cups a day.
• Several studies using patients have been published recently. They should be interpreted with caution, both because of possible flaws in their design and their small sample sizes.
  • One recent noteworthy study in patients with advanced hepatitis C-related liver disease suggests that regular, moderate coffee consumption is associated with lower rates of disease progression.
• It is not yet clear whether, and to what extent, caffeine is implicated in the inverse association between coffee consumption and these liver diseases. Several possible mechanisms are under investigation:
  • The main primary caffeine metabolite, paraxanthine, appears to suppress the synthesis of CTGF (connective tissue growth factor) via a cascade of control cycles, which subsequently slows down the progression of liver fibrosis, cirrhosis and liver cancer.
  • Other alternative mechanisms are related to the anti-carcinogenic effects of cafestol and kahweol, and possible antiviral effects of chlorogenic acids and caffeic acid.