Hu said that moderate coffee intake—about 2–5 cups a day—is linked to a lower likelihood of type 2 diabetes, heart disease, liver and endometrial cancers, Parkinson's disease, and depression. It's even possible that people who drink coffee can reduce their risk of early death.

It can help you focus, improve your mood and maybe even help you live longer. But how much is too much? Caffeine, a natural stimulant, can be found in a variety of foods, such as coffee beans, tea leaves, cacao beans, guarana berries and yerba maté leaves.

Low to moderate doses of caffeine (50–300 mg) may cause increased alertness, energy, and ability to concentrate, while higher doses may have negative effects such as anxiety, restlessness, insomnia, and increased heart rate. [2] Still, the cumulative research on coffee points in the direction of a health benefit.

Caffeine may cause a short, but dramatic increase in your blood pressure, even if you don't have high blood pressure. It's unclear what causes this spike in blood pressure. The blood pressure response to caffeine differs from person to person.