COFFEE CONSUMPTION AND CANCERS OF THE DIGESTIVE TRACT

No evidence for an effect of coffee on cancer of the oesophagus or stomach

Two recent large literature surveys, covering studies from Europe, North America and Asia reported an unchanged⁵, or reduced, risk of oesophageal cancer with the consumption of 3 or more cups of coffee a day⁶.

Another large review in 2006 found no association between coffee consumption and the risk of developing stomach cancer⁷.

Moderate coffee consumption linked to reduced risk of cancers of the mouth and throat

In a review of observational studies published over a 20 year period⁸, overall there appeared to be a 36% reduction in risk for cancers of the oral cavity/pharynx in those drinking between 3-5 cups of coffee a day versus those drinking less than 1 cup a day.  There was, however, no relationship between coffee consumption and laryngeal cancer.

A further large review of the literature confirmed that coffee consumption is linked to a lower risk of buccal and pharyngeal cancer⁵.

Moderate coffee consumption linked to reduced risk of liver cancer

Four meta-analyses^{5, 9-11} have reported a reduction in the risk of developing liver cancer with coffee consumption.  This reduction reached an overall level of 30% in coffee drinkers versus non-coffee drinkers with reductions as high as 55% in heavy coffee consumers.

Among a group at higher risk of developing liver cancer – chronic Hepatitis B virus carriers, moderate coffee drinkers appear to be at a lower risk of developing liver cancer than those who do not drink coffee¹².

Coffee consumption also appears to reduce the risk of Hepatitis C evolving to cancer by 22% for each cup of coffee consumed per day¹³, with a further reduction in disease progression of 62% in those consuming at least 3 cups a day.

Moderate coffee consumption not linked to higher risk of pancreatic cancer

Despite the positive results of studies looking at coffee consumption and pancreatic cancer in 1970 and 1981, the International Agency for Research on Cancer (IARC) now considers the evidence inadequate and attributes the results to confounding factors, including smoking⁹.

More recently, the World Cancer Research Fund (WCRF), in a report reviewing over 50 studies¹¹, found no increase in risk of developing pancreatic cancer with coffee consumption.

Since then, further studies, including four meta-analyses, have confirmed the absence of a relationship between moderate coffee consumption and increased risk of developing pancreatic cancer^{5, 14-17}. Some, but not all, of these most recent studies suggest that regular coffee drinking is linked to a lower risk of developing pancreatic cancer^5,14,15.

Moderate coffee consumption linked to reduced risk of colorectal cancer

Four large literature reviews, carried out over the last seven years looking at studies from Europe, Japan, the USA and South America, consistently suggest a favourable effect of moderate coffee consumption on colorectal cancer risk^5,18-20. Regular coffee drinkers appear to be up to 30% less likely to develop the disease than non-coffee drinkers. Further research is needed to confirm this link.