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Coffee: the magic bean to protect the liver?

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By Rachel Carter

25 Sep 2020

Rod Tucker discusses whether pharmacy teams should promote coffee drinking as a health promotion activity.

Annual consumption of coffee is huge. According to the international coffee organisation, global exports of coffee amounted to 10.57 million bags in June 2020.

As everyone knows, coffee contains the stimulant caffeine, and this was first isolated in the middle of the 19th Century by a German researcher, Ferdinand Runge. Many people feel unable to function properly without their morning fix of caffeine, and there is a there is a good deal of evidence to support the claim that caffeine is able to improve alertness and cognitive abilities.

Chemically, caffeine is a heterocyclic organic molecule with a purine base known as xanthine, and with two methyl groups attached to this heterocyclic ring, it is termed methylxanthine.

Although consumed for that morning ‘pick me up’, coffee has a surprisingly large number of potential therapeutic effects which lead to positive health outcomes. For example, in a comparative study of the antioxidant content of vegetables, wine and coffee, the latter was found to be the greatest single contributor to total antioxidant intake. In addition, coffee drinking may reduce the risk of type 2 diabetes, metabolic syndrome, gastric cancer and even death.

The amount of caffeine consumed depends on several different factors including how it is prepared, i.e., instant, percolated or brewed, the temperature of the water or the beans used. In one US analysis of commercial coffees, it was found that the caffeine content varied between 58 and 259mg/dose, with a mean value of 188mg. In the UK, for example, a Starbucks Grande, which is a double espresso, contains 150mg of caffeine.

Bioactives in coffee

Interestingly, the health benefits of coffee are not believed to be due to caffeine. Coffee contains a wide range of bioactive compounds, including diterpenes, cafestol and polyphenols such as chlorogenic acid, and it is these which are thought to be responsible for its health benefits.

Effects on the liver

Another possible benefit of coffee drinking relates to its effect on the liver and liver disease, which is a major cause of morbidity and mortality across the globe. For example, there has been an increase in the incidence of liver cirrhosis with analysis which included data from 187 countries, found that global deaths increased from approximately 650,000 in 1980 to over one million in 2010. Interestingly, there is evidence that consumption of coffee may have a protective effect on liver-related mortality. For example, in one prospective study of over 215,000 people and who were followed for over 18 years, it was found that those who drank two to three cups of coffee each day, had a 38% reduced risk of hepato-cellular carcinoma and this risk was reduced by 41% in those who drank four or more cups per day. Other work has suggested that regular consumption is associated with a lower rate of progression of advanced hepatitis C related liver disease.

Could coffee consumption therefore represent an affordable and effective intervention to reduce global liver-related mortality? This was the question posed in a recent study in which researchers sought to be calculate the global effect of coffee intake on liver disease. Using the global burden of disease 2016 data set which provided information for individuals for 112 countries, the authors estimated that there were approximately 1,240,201 deaths per year from liver disease. Their analysis revealed that the death rate could reduce by nearly half a million if per capita intake of two to three cups/day of coffee became embraced globally. Moreover, they estimated that by drinking four or more cups/day could lead to a reduction of more than 720,000 deaths.

One caveat attached to these estimates was that the impact across the globe varied because of the current differences of coffee intake. For example, there would be little effect on liver-related deaths in Europe, since the mean coffee intake was already two or more cups per day. In contrast, coffee drinking was far less common in areas such as South East Asia and Latin America where there was potentially much to be gained from drinking more coffee.

So, should pharmacy teams start promoting coffee drinking as a health promotion activity?

A comprehensive umbrella review of the health outcomes associated with coffee intake concluded that although there were a wide range of potential health benefits, there was a large and consistent effect for liver outcomes, and that consuming up to four cups per day was unlikely to lead to significant harm. Nevertheless, it is important to note that the data on the beneficial effects of coffee drinking have been derived from observational rather than randomised controlled trials, and so there remains a question over the robustness of these data. Furthermore, not everyone likes coffee – but there is some evidence that herbal tea consumption can also reduce liver stiffness, which is a proxy for fibrosis.

While coffee is unlikely to be a health panacea, pharmacy teams can reassure regular drinkers that coffee it not harmful, and that it just might improve their overall health and wellbeing.


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