What’s good for the heart is usually good for the brain; your brain needs healthy blood vessels, too. In one Swiss study, MRIs revealed that people who drank green tea had greater activity in the working-memory area of their brains. Green tea has also been shown to help block the formation of plaques that are linked to Alzheimer's disease.
Green tea seems to help keep blood sugar stable in people with diabetes. Because catechins lower cholesterol and blood pressure, they can help protect against the damage a high-fat diet can cause, Ochner says.