IDENTITY OF THE CHOLESTEROL-RAISING FACTOR FROM BOILED COFFEE AND ITSEFFECTS ON LIVER-FUNCTION ENZYMES

Boiled coffee contains an unidentified lipid that raises serum cholest erol. We studied the effects of the ingestion of coffee oil fractions of increasing purity in volunteers in order to identify the cholestero l-raising factor. In 15 volunteers who ingested 0.75 g/d of a non-trig lyceride fraction from coffee oil for 4 weeks, mean cholesterol increa sed by 48 mg/dl (1.2 mmol/l) relative to placebo. In contrast, a coffe e oil stripped of the non-triglyceride lipids cafestol and kahweol had no effect. In three volunteers, purified cafestol (73 mg/d) plus kahw eol (58 mg/d) increased cholesterol by 66 mg/dl (1.7 mmol/l) after 6 w eeks. Oil from Robusta beans, which contains cafestol but negligible k ahweol, also raised serum cholesterol. These findings show that cafest ol is at least partly responsible for the cholesterol-raising effect o f boiled coffee. Coffee oils and brews containing cafestol consistentl y increased serum triglycerides and alanine aminotransferase, and depr essed serum creatinine and gamma-glutamyltransferase (GGT). After with drawal GGT activity rose above baseline. Norwegians who habitually con sumed 5-9 cups of boiled coffee per day had higher serum cholesterol l evels and lower GGT but no higher alanine aminotransferase activity th an controls. Thus, serum cholesterol is raised by cafestol and possibl y also kahweol, both natural components of coffee beans. The mechanism of action is unknown but is accompanied by alterations in liver funct ion enzymes.