Coffee and Health: When a Daily Cup Can Become a Harmful Habit

International Coffee Day is renewing questions about the health effects of one of the world’s most popular drinks, including when a familiar daily ritual can become an unhealthy habit.

Coffee’s caffeine can boost alertness and help people feel less tired. The drink also contains antioxidant compounds, but its overall effect depends on how much is consumed and an individual’s sensitivity to caffeine.

Excessive caffeine can cause jitteriness, a racing heartbeat and difficulty sleeping. Drinking coffee late in the day may disrupt rest, while relying on it to compensate for inadequate sleep can reinforce an unhealthy routine.

How coffee is prepared matters, too: added sugar and rich toppings can make a cup more calorie-heavy. Paying attention to portion sizes, timing and symptoms can help drinkers judge whether their coffee habit is working for them or needs to change.