New Delhi, July 6 -- LOS ANGELES - For the 250 million people who pour a cup of coffee each morning, the habit has long occupied the hazy territory between pleasure and nutrition, more ritual than medicine. A study published July 1 in Clinical Gastroenterology and Hepatology - the largest of its kind ever conducted - suggests that territory has been mismapped. Researchers at Cedars-Sinai Medical Center, tracking nearly 355,000 people over 13 years, found that regular coffee drinkers had dramatically lower rates of liver cancer, cirrhosis, and liver-related death than those who drank none. For the first time, MRI scans of those drinkers' livers showed why.

The numbers are striking even by clinical-trial standards. Participants who consume...