Coffee consumption is highly prevalent with more than half of all Americans over 18 drinking on average three cups each day according to a 2010 report from the National Coffee Association. Moreover, the International Coffee Association reports that coffee consumption has increased one percent each year since the 1980s, increasing to two percent in recent years. Previous studies found that coffee consumption may help lower the risk of developing diabetes, cardiovascular disease, non-alcoholic fatty liver disease, cirrhosis, and liver cancer.
“Prior research found that drinking coffee may have a possible protective effect on the liver. However, the evidence is not clear if that benefit may extend to decaffeinated coffee,” explains lead researcher Dr. Qian Xiao from the National Cancer Institute in Bethesda, Maryland.
For the present study researchers used data from the U.S. National Health and Nutrition Examination Survey (NHANES, 1999-2010). The study population included 27,793 participants, 20 years of age or older, who provided coffee intake in a 24-hour period. The team measured blood levels of several markers of liver function, including aminotransferase (ALT), aminotransferase (AST), alkaline phosphatase (ALP) and gamma glutamyl transaminase (GGT) to determine liver health.
Participants who reported drinking three or more cups of coffee per day had lower levels of ALT, AST, ALP and GGT compared to those not consuming any coffee. Researchers also found low levels of these liver enzymes in participants drinking only decaffeinated coffee.
Dr. Xiao concludes, “Our findings link total and decaffeinated coffee intake to lower liver enzyme levels. These data suggest that ingredients in coffee, other than caffeine, may promote liver health. Further studies are needed to identify these components.”