Coffee May Increase Life Expectancy in Liver Disease

Two recent publications from the United States and Europe have again focused attention on the positive effects of coffee in reducing all-cause human mortality.^[1,2] Furthermore, other studies are adding to our knowledge of coffee's potential ability to reduce the risk for liver disease and its progression. These studies led me to update the information regarding coffee and its beneficial clinical effects.

Coffee is consumed worldwide. Although we may not yet understand the mechanisms of coffee's positive effects,^[3,4] a growing number of publications continue to indicate that it can benefit persons with liver disease, slow formation of liver fibrosis, reduce the risk for hepatocellular carcinoma even in persons without cirrhosis, and lower overall mortality in people with or without liver disease.

Reduces All-Cause Human Mortality

Whereas past studies have questioned the safety of excess coffee consumption (and therefore of excess caffeine), recent reports suggest that adults can consume up to 400 mg of caffeine daily without significant risk.^[5] This is the amount of caffeine in four 8-ounce cups of regular coffee. Of course, many of us know from observing others or through personal experience that many Americans consume more than four cups of coffee daily.

In a US study of coffee intake and its effects on all-cause mortality, 185,000 multiethnic persons of African American, Latino, Hawaii American, Japanese American, and non-Hispanic white heritage were included.^[1] Dietary history, lifestyle factors, smoking and medical history, education level, amount of physical activity and alcohol intake, body mass index (BMI), and any evidence of preexisting chronic disease were obtained from all patients. Intake of both caffeinated and decaffeinated coffee was defined by dietary history as never, one to three cups per month, one to six cups per week, one cup per day, two to three cups per day, and four or more cups daily. Persons who drank exclusively caffeinated or decaffeinated coffee were separately identified.

The study found that persons who drank greater quantities of coffee were typically younger, male, white, smokers, and alcohol consumers, and had less evidence of preexisting chronic disease. After adjustment for smoking, increasing coffee consumption was associated with reduced risk for mortality. These findings included reduction in mortality from heart disease, chronic lung disease, stroke, diabetes mellitus, and kidney disorders. The reduction of all-cause mortality in coffee drinkers was present in both smokers and nonsmokers and was similar for all races and ethnicities. Furthermore, the effect of coffee intake on mortality reduction occurred whether the coffee was exclusively caffeinated or decaffeinated.

The European study evaluated more than 450,000 persons from 10 different countries.^[2] Dietary intake, daily consumption of caffeinated or decaffeinated coffee, lifestyle, smoking and alcohol history, medical history, physical examination, and selected laboratory values were determined. Total follow-up of patients was over more than 16 years. In that study, it was similarly observed that those with greater coffee intake tended to be younger, be active smokers, have greater red meat and alcohol intake, and be less likely to consume vegetables and fruit on a daily basis. Again, men and women in the highest quartile of coffee intake had lower all-cause mortality, an effect which was evident regardless of whether the coffee consumed contained caffeine.

"These data and those supporting the reduction of all-cause mortality with coffee intake indicate that it may be time to recommend coffee as part of a healthy diet."

The European study also noted that coffee intake caused a reduced risk for death in patients with known liver disease, even in the presence of advanced cirrhosis or hepatocellular carcinoma. Coffee consumption also reduced the risk for progression of alcoholic or nonalcoholic cirrhosis in both men and women. When nonsmokers were evaluated, high coffee intake reduced all-cause mortality from cancer, circulatory disorders, and digestive and respiratory diseases.

These publications and others add to the known beneficial effect of coffee on patients with Parkinson disease, diabetes mellitus, stroke, gallbladder disease, and chronic liver disorders.^[6] One recent systematic review also suggested that habitual coffee intake will reduce the risk for type 2 diabetes mellitus.^[7]

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