Moderate caffeine may benefit health, with caveats about energy drinks

New research indicates that about 400 mg of caffeine per day—roughly three to five cups of coffee or tea—is generally safe for most adults and is linked to lower risks of heart disease, stroke, heart attack, hypertension, diabetes, and atrial fibrillation, plus a reduced risk of Parkinson’s disease, while also boosting alertness. However, high caffeine intake can cause anxiety, jitters, stomach issues, and sleep problems; benefits mainly come from natural caffeine in coffee, tea, and chocolate, with limited or potential harms from energy drinks and synthetic caffeine.