Science Finds Exactly the Right Amount of Coffee You Should Drink a Day

Four cups of strong coffee a day might be the recipe for a healthy heart, especially for older adults.

A team of German researchers, led by the molecular biologists, thinks it has discovered clues about how coffee works. Its caffeine-fueled magic on our heart health and how much caffeine we should drink each day to see the best benefits.

By studying caffeinated lab mice and dosing human tissues with caffeine, the researchers discovered how a jolt of the stimulant could improve the way cells inside our blood vessels work. By making certain proteins inside older adult cells perform more like young and nimble ones.

"When you drink four to five cups of espresso, that seems to improve the function of the powerhouses of our cells, and therefore seems to be protective."

Scientists have for years noticed that people who drink coffee seem to be less likely to die from all sorts of causes, including heart disease, stroke, or diabetes.

Coffee is also associated with a whole host of other health benefits, including a lower risk of liver disease (cirrhosis), a lower risk of developing certain kinds of cancer, lower rates of dementia and Alzheimer's, and a reduced risk of depression. It's also great for your heart.

If you don't like the taste, green tea has similar levels of caffeine and could also be an effective way to boost heart health. It's important not to overdo it with the new recommendation, as too much coffee can quicken your heartbeat and cause other health problems. But drinking up to six cups a day should be OK.

One caveat: The study wasn't done in humans - only in human tissues and lab mice. What works in a hyper-controlled environment of mice, dosed with very specific amounts of caffeine, may not be the same as what happens when you drink a cup of joe at home.