For a number of decades there has been controversy about the potential health benefits or evil of an ancient herbal beverage called coffee. The first documented use of coffee was in Ethiopia during the 11th century. Since then its production and use have spread around the world.

Of course, not all herbal beverages are good for your health, and coffee has a high concentration of caffeine, a naturally occurring stimulant. Consequently, the effect of coffee consumption on health has been debated for decades — perhaps centuries.

QUESTION: What is the latest research on coffee and health?

ANSWER: Two large studies were published this month in the Annals of Internal Medicine: the European Prospective Investigation Into Cancer and Nutrition (EPIC) study and the Multiethnic Cohort (MEC) study, which was based on data from people in Hawaii and California.

The EPIC study analyzed data from over 500,000 people age 35 and older from 10 European countries. The MEC study was based on more than 185,000 people age 45 and up from Hawaii and Los Angeles. Both of these studies followed people for about 16 years, and the findings are quite interesting.

Q: What did these studies find?

A: Their basic conclusions were similar: Higher coffee consumption was associated with a reduced risk of death and the major diseases that tend to cause death. The EPIC study found this association was the same across the 10 countries studied despite a wide variety of coffee preparation techniques and forms of consumption. Even decaffeinated coffee was protective. The MEC study found the reduced risk of death associated with higher coffee consumption was the same for African-Americans, Japanese-Americans, Latinos and whites.

Of local interest, the MEC study is an ongoing collaboration between the University of Hawaii Cancer Center and the University of Southern California Keck School of Medicine. Combining data from Hawaii with data from Southern California provides information on health-risk factors that might differ in various racial and ethnic groups.

Q: What limitations do these studies have?

A: Due to their designs, these studies identify associations between things like coffee consumption and conditions like diabetes, heart disease, cancer, etc. They do not establish “cause and effect” conclusions about coffee, but the large participant number is a strength.

Q: Does adding cream and sugar affect coffee’s apparent benefits?

A: This was not reported in these studies, but it is likely that coffee with “additives” still has the same benefits. Of course, cream and sugar will add calories.

Q: How much caffeine is too much?

A: Other studies have indicated that up to 400 milligrams of caffeine per day (300 mg/day during pregnancy) is not associated with known negative effects. However, people can vary considerably in their sensitivity to the stimulant effects of caffeine.

Q: What’s the bottom line on coffee and health?

A: Although it is not scientifically conclusive that coffee consumption prevents chronic diseases, it seems safe to say that moderate coffee intake (three to five cups a day providing up to 400 mg of caffeine) is not associated with adverse health effects, and that coffee can be part of a healthy diet for most people.

Alan Titchenal, Ph.D., C.N.S., and Joannie Dobbs, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa. Dobbs also works with University Health Services.