Studies link moderate caffeine consumption to a decrease in type 2 diabetes and to better defenses against endometrial cancer and possibly Alzheimer’s disease. Plus, both coffee and tea are rich in the antioxidants that may help lower the risk of stroke. Even more compelling, recent research published in the Journal of Investigative Dermatology shows that caffeine may offer protection against sun damage. However, other reports suggest that too much can cause breast cysts, migraines, and, you guessed it, sleep problems.
The middle ground: For most, 200 to 300 milligrams of caffeine―about two cups of coffee daily―is plenty.