Coffee and disease: an overview with main emphasis on blood lipids and homocysteine Dag S. Thelle 1,2 and Elisabeth Strandhagen 1 1 Cardiovascular Institute, Department of Medicine, Sahlgrenska University Hospital/O ¨ stra, Go ¨teborg, Sweden; 2 Institute of Clinical Epidemiology and Molecular Biology, Akershus Unversity Hospital, Oslo, Norway Abstract The issue of whether coffee is detrimental or beneficial to health has been studied in a large number of observational and clinical studies. Some observational studies have shown an association between coffee and coronary heart disease (CHD), while others have not. Both clinical trials and observational studies have shown that coffee consumption affects some CHD risk factors, e.g. plasma total homocysteine and serum total cholesterol. Studies on the association between coffee consumption and health have shown protective effects against type 2 diabetes, Parkinson’s disease and Alzheimer’s disease, whereas the protective effect against certain forms of cancer and possible hazards with regard to reproductive health are still debated. This review reports on the association between coffee intake and homocysteine and blood lipids in light of the results of studies by this group. A review of published papers on the relevant issues found that protective effects of coffee have been reported for type 2 diabetes, Parkinson’s disease and Alzheimer’s disease. These results are based on observational studies. More studies with adequate control of confounding variables are needed to confirm these findings. Thereare at present no relevant biological explanations for any protective effect. Studies by this group have confirmed that even filtered coffee has a total cholesterol-increasing effect. Whether this is due to changes in filter-paper quality or other unknown mechanisms is not clear. The homocysteine-raising effect of coffee is mainly seen among subjects with the methylenetetrahydrofolate reductase (MTHFR) 677TT polymorphism, demonstrating a nutrition /gene effect modification. In conclusion, the effects of coffee on blood lipids and plasma homocysteine are firmly based, but the studies reflect a certain heterogeneity, in part explained by genetic susceptibility. The coffee /health issue is still pending; there are certain firmly established biological effects of coffee intake, but the impact on future health is virtually unknown. Keywords: blood lipids; coffee; coronary heart disease; homocysteine; reproductive hazards Received: 17 January 2005; Revised: 21 March 2005; Accepted: 31 March 2005 Introduction The issue of whether coffee is detrimental or beneficial to health is not new. King Gustav III of Sweden (1746  /1792) decided that coffee was pure poison. To prove the truth of this theory he granted amnesty to a murderer who was condemned to death, and ordered him to drink coffee every day until he died. As a control he granted amnesty to another murderer, on condition that he should drink tea every day. Two doctors were designated to look after the experiment and assess the out- come. In this case, the doctors were the first to die. Then, the king was murdered in 1792. As time went by the first one of the two criminals died, 83 years old: it was the tea drinker. The consequence of the experiment was not taken into account. Drinking coffee was forbidden in Sweden in 1794 and in 1822. History of coffee The coffee tree probably originated in the province of Kaffa, in the area known today as Ethiopia. It is not known exactly when, or how, it was first discovered that a rich and stimulating brew could be made from the coffee bean. Before coffee was consumed as a beverage, people may have chewed the cherries and beans. There is evidence to suggest that coffee trees were cultivated 1000 years ago. The first reports of commercial cultivation are from Yemen in the fifteenth century. æ Review article 50 # 2005 Taylor & Francis ISSN 1102-6480 Scandinavian Journal of Nutrition 2005; 49 (2): 50 /61 DOI: 10.1080/11026480510037138