A European research team, undertaking the most comprehensive study of caffeine and health in the world, has found people drinking more than six cups of coffee daily are at increased risk of heart attack, especially if they smoke.
The team from the Mario Negri Instituto in Italy added however that moderate consumption of coffee (up to three cups per day of espresso or mocha) does not affect risk for acute myocardial infarction (heart attack).
Found in greatest quantities in coffee and tea, but also in some cola drinks and chocolate, caffeine has in recent years been used in functional foods to stimulate the brain and temporarily avert fatigue.
However there is evidence that the natural chemical can also have negative physiological effects, such as raising blood pressure. This is why regular consumption of too much caffeine during pregnancy is discouraged. And although moderate amounts of caffeine can be consumed safely as part of a healthy, balanced diet, there is little evidence of any long-term benefit of caffeine consumption.
The 'Caffeine and Health' project brings together a large multidisciplinary team of scientists and consumer organisations, with the general aim of improving understanding about caffeine, consumed by more than 90 per cent of Europe's population everyday.
Other results reported so far, include findings from a case-control study, showing an inverse association between coffee drinking and alcohol-related cirrhosis, (which is strongly related to liver cancer), but the mechanisms of this association remain unclear. However, scientists did not observe this inverse relationship between the disease and decaffeinated coffee, tea or cola drinks.
Researchers from institutions including the National University of Ireland, the University of Bristol in the UK and the University of Nijmegen in the Netherlands are planning to also examine the acute and chronic effects of caffeine on blood pressure and mental performance and how caffeine withdrawal impacts behaviour. They are to determine the effects of maternal caffeine consumption using rat and mouse offspring and will assess disease risk associated with the chemical.
Full results of the different studies will be available in early 2004, but more information may be obtained from the coordinator Prof Jack James at the Department of Psychology in theNational University of Ireland, or the project website.