Caffeine and health.

"Caffeine is probably the world's most popular drug."' In coffee, tea, cola drinks, cocoa, chocolate, and sometimes proprietary medicines, it is taken regularly by most of the population from childhood onwards. Given its wide consumption, the health hazards are few, but caffeine has been attacked for a statistical association with various diseases. Many ofthese ghosts have-now been banished: fears of a causative role in urinary tract24 and pancreatic cancer,57 teratogenesis," 9 spontaneous abortion,'0 and fibrocystic breast disease"' 12 have largely been dispelled. '3-33 The relation ofcaffeine to ischaemic heart disease is harder to resolve. A large Norwegian study showed a strong, independent, positive relation between coffee consumption and serum total cholesterol and triglyceride concentrations.34 Evidence from other countries, however, is conflicting.354' Discrepancies may partly depend on the methods ofprepara- tion: Norwegians traditionally boil coffee (100-500 mg caffeine/cup) while other Europeans and Americans drink percolated (100-150 mg caffeine/cup), drip brewed (100- 120 mg), or instant coffee (80-100 mg).' Intervention studies suggest that boiled but not filtered coffee raises the serum cholesterol concentration,4243 possibly by reducing bile secretion, which might account for the lowered incidence of colonic cancer in coffee drinkers.,"