The whole truth about coffee.

The headlines about coffee's impact on your health seem to change as quickly as the time it takes to drink a cup, says Consumer Reports. Should you savor every drop or try to cut down? Here's what we know right now:

It may lengthen your life. True, coffee drinkers are more likely than nondrinkers to smoke, eat red meat, skimp on exercise and have other life-shortening habits, according to a 2012 study in the New England Journal of Medicine. But when researchers took those factors into account, they found that people ages 50 to 71 who drank at least one cup of coffee per day lowered their risk of dying from diabetes, heart disease or other health problems when followed for more than a decade. That may be due to beneficial compounds such as antioxidants -- which might ward off disease -- and not caffeine. Decaf drinkers had the same results.

It may make you happier. Coffee is not just a pick-me-up; it also has been linked to a lower risk of depression. In a study led by the Harvard School of Public Health that tracked 50,000 women for 10 years, those who drank four or more cups of caffeinated coffee per day were 20 percent less likely to develop depression than nondrinkers. Another study found that adults who drank two to four cups of caffeinated coffee were about half as likely to attempt suicide as decaf drinkers or abstainers. The researchers speculated that long-term coffee drinking may boost the production of "feel-good'' hormones such as dopamine.

It contains many good-for-you chemicals. For most Americans who drink coffee, it provides more antioxidants than any other food, according to Dr. Joe Vinson, a chemistry professor at the University of Scranton. But Consumer Reports notes that it's also a top source of acrylamide, a chemical whose link to cancer is being investigated.

It may cut...