Drinking decaffeinated coffee is just as helpful as drinking regular coffee is for maintaining a healthy liver, a new study finds.
Regardless of whether they drank decaf or regular, people in the study who drank large quantities of coffee on a daily basis had lower levels of abnormal liver enzymes, the researchers found. This suggests that a chemical in coffee other than caffeine may help the liver, the researchers said.
Other studies have found that drinking coffee is associated with lower risks of developing diabetes, cardiovascular disease, nonalcoholic fatty liver disease, cirrhosis and liver cancer. [10 Things You Need to Know About Coffee]
"Prior research found that drinking coffee may have a possible protective effect on the liver," lead researcher Dr. Qian Xiao, of the National Cancer Institute in Bethesda, Maryland, said in a statement. "However, the evidence is not clear if that benefit may extend to decaffeinated coffee."
To answer the decaf question, Xiao and his colleagues used data from the National Health and Nutrition Examination Survey, which is a survey conducted by the Centers for Disease Control and Prevention to assess the health of people living in the United States. In this survey, participants are not only interviewed, they also undergo physical examinations including blood tests.
The researchers looked at about 27,800 people age 20 or older who reported how much coffee they had consumed over the past 24 hours. The team also looked at their blood samples for several markers of liver health, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and gamma-glutamyl transaminase (GGT). Elevated levels of liver enzymes may be a sign of liver damage or inflammation.
The results showed that people who said they drank three or more cups of coffee a day had lower levels of all four of these enzymes, compared with people who did not drink any coffee. Surprisingly, it didn't matter whether a person drank regular or decaf coffee: the effect on liver enzyme levels was almost identical.
"Our findings link total and decaffeinated coffee intake to lower liver enzyme levels," Xiao said. Further studies are needed to identify what component of coffee is responsible for this effect, he said.
The study will be published in an upcoming issue of the journal Hepatology.
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Laura is the archaeology and Life's Little Mysteries editor at Live Science. She also reports on general science, including paleontology. Her work has appeared in The New York Times, Scholastic, Popular Science and Spectrum, a site on autism research. She has won multiple awards from the Society of Professional Journalists and the Washington Newspaper Publishers Association for her reporting at a weekly newspaper near Seattle. Laura holds a bachelor's degree in English literature and psychology from Washington University in St. Louis and a master's degree in science writing from NYU.