In the United States, coffee is the most commonly consumed beverage, second only to water. The effects of drinking coffee depend on the amount and type of coffee you drink, but in general it has a beneficial effect on health for adults as long as it's consumed in moderation. Children and adolescents, however, may be better off avoiding coffee.
Potential Health Benefits
Drinking 2 to 3 cups of coffee per day has either neutral or beneficial effects on adults in terms of heart disease, stroke, neurodegenerative diseases, gastrointestinal diseases and asthma, according to a review article published in the Journal of the American College of Cardiology in September 2013.
Another review article, published in The New England Journal of Medicine in May 2012, came to a similar conclusion, saying that the antioxidants and other active compounds in coffee may help lower the risk for heart disease, diabetes, inflammatory diseases stroke and early mortality.
Drinking a moderate amount of coffee during meals may also help you eat less, potentially making it easier to lose weight, according to a study published in Obesity in June 2013.
Potential Health Risks
Coffee may interfere with oral contraceptives and postmenopausal hormones and isn't recommended for pregnant women or women with postmenopausal problems. It can also cause caffeine withdrawal symptoms if you suddenly decrease your intake. These symptoms include headache, trouble concentrating, fatigue, nausea, muscle pain, depression and irritability.
Getting too much caffeine from coffee can make you jittery, cause dehydration, increase your blood pressure, cause abnormal heart rhythms, make it hard to sleep, increase the risk of dehydration, make you dizzy or give you headaches. Too much caffeine may also increase your risk for osteoporosis or fibrocystic disease, which causes lumpy, painful breasts.
While coffee is fine in moderation for adults, it may be harmful for children and teenagers. A study published in the Journal of Adolescence in April 2011 found that teenagers who consumed higher amounts of caffeine were more likely to be sleepy during the daytime and be academic underachievers. Caffeine may affect brain development when used during the formative years and is associated with more risk-taking behaviors in adolescents, according to the National Council on Strength & Fitness.
The National Center on Addiction and Substance Abuse at Columbia University also notes that girls who drink coffee are more likely to smoke and drink alcohol than those who do not.
Speak with your doctor to determine a safe amount of coffee for you to drink. In general, adults should drink no more than two or three 8-ounce cups of caffeinated coffee per day and limit total caffeine to no more than 200 to 300 milligrams daily. Some people are particularly sensitive to caffeine and may need to limit their caffeine intake even more. If you want to drink more coffee than this or drink coffee in the late afternoon or evening, choose decaffeinated coffee.