Previous research has shown that coffee consumption can benefit the liver, but a new study indicates that drinking decaf also lowers liver enzyme levels, suggesting the benefits are not linked to caffeine content.
As autumn settles in and the temperatures drop, starting the day with a steaming cup of coffee becomes even more appealing; and this is a daily habit that recent research has linked to certain health benefits.
Americans are definitely gravitating toward coffee as part of their daily diet; according to a 2010 report from the National Coffee Association, more than 50% of all Americans over age 18 drink around three cups each day.
What is more, the International Coffee Association say coffee consumption has increased 1% each year since the 1980s, and in recent years, this figure has jumped to 2%.
The researchers of this latest study - led by Dr. Qian Xiao from the National Cancer Institute in Bethesda, MD - publish their findings in the journal Hepatology.
"Prior research found that drinking coffee may have a possible protective effect on the liver," says Dr. Xiao. "However, the evidence is not clear if that benefit may extend to decaffeinated coffee."
'Ingredients in coffee other than caffeine may promote liver health'
To further investigate, the team employed data from the US National Health and Nutrition Examination Survey (NHANES) 1999-2010. Participant numbers totaled over 27,000, and the subjects were 20 years of age and older.
- Americans drink an average of 3.1 cups of coffee a day, with an average cup size of 9 oz
- 65% of American coffee drinkers drink the beverage with breakfast
- The US spends a total of $40 billion on coffee each year.
Each participant provided a 24-hour dietary recall to report their coffee intake, and the researchers measured blood levels of liver function markers to assess liver health - including aminotransferase (ALT), aminotransferase (AST), alkaline phosphatase (ALP) and gamma glutamyl transaminase (GGT).
Results revealed that participants who drank three or more cups of coffee per day had lower levels of all four liver enzymes, compared with those who did not drink any coffee. Additionally, the team found these same results in participants who only drank decaf coffee.
"Our findings link total and decaffeinated coffee intake to lower liver enzyme levels," says Dr. Xiao. "These data suggest that ingredients in coffee, other than caffeine, may promote liver health. Further studies are needed to identify these components."
Medical News Today recently reported on a study that suggested coffee drinking habits are driven by genetics. Researchers from Harvard School of Public Health and Brigham and Women's Hospital in Boston, MA, identified two gene variants related to caffeine metabolism and two gene variants that may influence the "rewarding" effect of caffeine.
The researchers said their findings suggest coffee intake is "naturally modulated" by individuals so they can experience the optimal effects of caffeine.
In January of this year, we also wrote a spotlight feature on how caffeine affects our health.