COMMENTARY

Coffee May Increase Life Expectancy in Liver Disease

Rowen K. Zetterman, MD

Disclosures

November 07, 2017

Reduces the Risk for Cancer

Recent studies back up earlier findings that coffee reduces cancer risk.[8,9] In a meta-analysis of 105 individual studies,[8] coffee intake was associated with a reduced risk for cancers of the liver, oropharynx, colon, prostate, and endometrium, as well as melanoma.

Controversy remains, however, regarding the relationship of coffee and the risk for lung cancer. Some meta-analyses suggest that coffee may actually increase the risk for lung cancer,[8] whereas other summary reports suggest no effect on lung cancer risk.[9] In the NIH-AARP Diet and Health Study,[10] coffee drinking appeared to increase the risk for lung cancer, although when subject smoking was taken into account, the evidence for coffee and increased lung cancer risk was reduced. And in a systematic review of eight prospective cohorts and 13 case-control studies,[11] coffee drinkers who were also nonsmokers did not have an increased risk for lung cancer. It is evident that additional studies of the relationship of coffee and lung cancer risk are needed.

Reduces the Development for Liver Fibrosis 

Circulating aminotransferase[12,13] and gamma-glutamyltransferase[14] levels are reduced in patients with significant coffee intake, even in the presence of added alcohol drinking.[12] Whether this effect of coffee on liver tests is an indicator of reduced liver injury or just a pharmacologic effect of coffee on the enzyme levels themselves is unclear.

An assessment of the US multiethnic population indicated that coffee intake reduced death rates from liver disease.[15] This mortality reduction occurred despite concurrent alcohol consumption, smoking, underlying diabetes mellitus, gender, ethnicity, or BMI. The effect on mortality was prominent—four or more cups of coffee daily reduced the death rate from liver disease by 71%. In the European study of all-cause mortality,[2] individuals with more coffee consumption had significantly lower levels on liver tests and higher albumin levels. These effects were noted whether the coffee contained caffeine or not.

Meta-analyses and systematic reviews of patients with liver fibrosis and/or cirrhosis have noted a benefit to coffee consumption in slowing overall progression of liver disease or in preventing cirrhosis.[16,17,18,19,20] Although some attribute this effect to the presence of caffeine in coffee, the many other constituents of coffee and the finding that decaffeinated coffee also reduces disease progression suggest that caffeine alone may not be the associated factor.

The benefit of coffee also extends to persons who already have advanced liver disease. Coffee intake improves actuarial survival of those with known cirrhosis awaiting liver transplantation and improves survival after liver transplantation.[17]

I was also drawn to a longitudinal study of a Dutch cohort being evaluated for evidence of liver disease, including fatty liver by ultrasound and liver fibrosis determined as liver stiffness on transient elastography.[20] Approximately 35% of patients in this study had fatty liver disease, and 5% had evidence of liver fibrosis. When fatty liver disease is present, there is a greater likelihood of liver fibrosis. When these findings were compared with coffee and herbal tea consumption, intake of three or more cups of coffee or herbal tea daily reduced the likelihood of developing liver fibrosis. However, coffee and tea did not affect the development of fatty liver.

This important longitudinal study looking for liver fibrosis in an otherwise presumed healthy population should give us important information on risk factors. Because we will never pursue a randomized controlled trial of coffee and liver disease, we need more longitudinal studies that look for factors that increase the risk for fibrosis or cirrhosis progression. Studies of lifestyle, dietary habits, and geographic and medical issues; intake of coffee, tea, other caffeinated beverages, and alcohol; and tests for known causes of progressive liver injury, such as nonalcoholic fatty liver disease (NAFLD), can teach us much about liver disease progression. Such prospective longitudinal studies may give us our best evidence on factors that prevent or slow liver disease progression.

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