(American Journal of Clinical Nutrition) -- Elevated serum concentrations of homocysteine (tHcy) and cholesterol are associated with increased risk of ischemic heart disease (IHD). Previous studies found that consumption of large amounts of unfiltered coffee resulted in increases in serum tHcy and cholesterol, suggesting a specific effect related to brewing methods.

In a new study in the American Journal of Clinical Nutrition, Christensen et al. studied a group of healthy nonsmoking volunteers, 47% of whom drank filtered caffeinated coffee an average of 4.9 cups per day. Cholesterol and tHcy levels went down in those subjects who abstained from filtered coffee, indicating that refraining from commonly consumed amounts of coffee could contribute to a long-term reduction in IHD risk.

One-hundred-eighty-three Norwegian men and women, aged 24-69 years, were randomly assigned to 3 groups and instructed to either abstain from coffee, drink 1-3 cups daily, or ≥4 cups daily. After 6 weeks, abstention from coffee resulted in decreases in total cholesterol and tHcy, as well as a significant increase in levels of the B vitamin folate. Because folate is an important determinant of serum tHcy concentrations, the rise in folate concentrations may have been the cause of the decline in tHcy. Total cholesterol, tHcy, and serum folate concentrations were unchanged in both groups of coffee drinkers. Extrapolating these results to long-term risk for IHD, abstaining from 4 cups/day of coffee would reduce cholesterol-related risk of IHD by 15% and tHcy-related risk of IHD by 10%.

The authors conclude that relative elevations of tHcy and cholesterol are caused by compounds such as terpenoids, which are only partially removed from coffee in the filtering process.