Brain and Nervous System
Unlike high levels of caffeine found in coffee, the low amounts in black tea promote blood flow in the brain without over stimulating the heart. The caffeine in black tea hones mental focus and concentration and studies show that the amino acid L-theanine found in black tea can help you relax and concentrate more fully on tasks. Black tea has been shown to reduce levels of the stress hormone cortisol after a month of drinking four cups of tea daily. The caffeine in black tea might also give your memory the boost it needs for a few hours and some studies suggest that a regular tea habit may help protect against Parkinson's disease.