Dr. Inoue-Choi said that black tea, “even at higher levels of intake, can be part of a healthy diet.”

However, the current study found no further health benefits after the third daily cuppa. And tea contains caffeine, which can have adverse effects at high consumption levels.

Small amounts of caffeine have been shown to enhance cognitive function and alertness and help with weight loss. Larger amounts—more than 400mg per day—can cause problems, such as jitters and shakes, disrupted sleep, heartburn, and even high blood pressure in some people.

However, on average, three cups of tea contain around 180mg of caffeine, so it should not cause problems for anyone who is not caffeine-sensitive.