Among more than 170,000 people in the U.K., those who drank about two to four cups of coffee a day, with or without sugar, had a lower rate of death than those who didn't drink coffee, reported lead author Dan Liu, MD, of the School of Public Health at Southern Medical University in Guangdong, China.
"Previous observational studies have suggested an association between coffee intake and reduced risk for death, but they did not distinguish between coffee consumed with sugar or artificial sweeteners and coffee consumed without," wrote Liu and colleagues in the journal Annals of Internal Medicine.
To learn more, the investigators turned to the U.K. Biobank, which recruited about half a million people between 2006 and 2010 to take part in questionnaires, interviews, physical measurements, and medical tests.
Out of this group, 171,616 of them completed at least one dietary questionnaire and met the criteria for the coffee study.
Results showed that 55.4% of them drank coffee without any sweetener, 14.3% drank coffee with sugar, 6.1% drank coffee with artificial sweetener, and 24.2% did not drink coffee at all. Coffee drinkers were further sorted into groups based on how many cups of coffee they drank per day.
Coffee Drinkers Were Significantly Less Likely to Die
Over the course of about 7 years, 3,177 of the people being studied died, including 1,725 who from cancer and 628 from heart disease.
After accounting for other things that might impact their risk of death, like lifestyle choices, the investigators found that coffee drinkers were significantly less likely to die from any cause, heart disease, or cancer than those who didn't drink coffee at all.
This benefit was seen across types of coffee, including ground, instant, and decaffeinated. The protective effects of coffee were greatest in people who drank about two to four cups a day, among whom death was about 30% less likely, regardless of whether they added sugar to their coffee.
People who drank coffee with artificial sweeteners did not live significantly longer than those who drank no coffee at all.
Experts Urge Caution Despite New Findings
Although the study results suggest that adding sugar did not eliminate the health benefits of coffee, Liu and colleagues still cautioned against sweetened beverages, because of the widely known links between sugar consumption and poor health.
Estefanía Toledo, MD, PhD, of the Department of Preventive Medicine and Public Health at the University of Navarra in Spain, offered a similar takeaway.
Toledo, who previously published a study showing a link between coffee and extended survival, says moderate coffee consumption has "repeatedly" been associated with lower rates of "several chronic diseases" and death, but there still isn't enough evidence to recommend coffee for those who don't already drink it.
More long-term research is needed, she says, ideally with studies comparing changes in coffee consumption and health outcomes over time.