A review of more than 200 studies found coffee consumption was "more often associated with benefit than harm," adding even people who drank as many as seven cups of coffee were likely to be safe.
Researchers at the University of Southampton in the U.K. gathered observational data on the impact of coffee on all aspects of the human body and published the results in the British Medical Journal on Tuesday.
Health experts warned people should not start drinking coffee, or increasing their intake, for health reasons. Too much coffee for women during pregnancy could also be harmful, the study said.
The study found that compared to non-coffee drinkers, those who consumed three cups of coffee each day appeared to reduce their risk of being diagnosed with heart problems. Drinking coffee was also linked to a lower risk of diabetes, liver disease, dementia and some cancers.
Meantime, while three of four cups of coffee was likely to be the optimum number, those who drank as many as seven cups a day still appeared to benefit, the study said.
"Coffee is one of the most commonly consumed beverages worldwide," the researchers said.
"As such, even small individual health effects could be important on a population scale … Coffee consumption seems generally safe within usual levels of intake, with summary estimates indicating largest risk reduction for various health outcomes at three to four cups a day, and more likely to benefit health than harm."
Previous research found that regular coffee consumption could be linked to a reduced risk of chronic diseases - whether people choose to drink caffeinated or not.