Coffee is one of the world’s most popular drinks, and research suggests that moderate amounts can be part of a healthy diet. It is also a major source of antioxidants in many diets. Here are the main benefits, what is safe, and who should cut back.
10 possible benefits
- More energy and alertness: caffeine blocks adenosine, the signal that makes you feel sleepy.
- Better focus and mood: it can improve attention and reaction time.
- Brain health: regular coffee drinking is linked with a lower risk of Parkinson’s disease and possibly Alzheimer’s disease.
- Type 2 diabetes: habitual drinkers have a lower risk in many studies.
- Liver: coffee is associated with a lower risk of liver disease, fatty liver progression and liver cancer.
- Heart: moderate intake is linked with no increase, and possibly a lower risk, of heart disease and stroke.
- Exercise performance: caffeine can improve endurance and reduce perceived effort; 3 mg per kg of body weight an hour before exercise is typical in studies.
- Antioxidants: coffee contains chlorogenic acids and other polyphenols.
- Depression: some studies link regular coffee to a lower risk.
- Longevity: large studies link 2 to 4 cups a day with a lower risk of early death.
Most of these findings come from observational studies, so they show association, not proof. Coffee is not a treatment for any disease.
How much caffeine is safe?
- Up to 400 mg of caffeine a day for most healthy adults, about 3 to 4 cups of brewed coffee.
- Up to 200 mg a day during pregnancy, as advised by many health authorities; discuss with your doctor.
- For teenagers, no more than 100 mg a day is commonly advised.
Typical caffeine: brewed coffee (240 ml) 95 mg; espresso (30 ml) 63 mg; instant coffee 60 mg; black tea 47 mg; green tea 28 mg; cola 34 mg; decaf 2 to 5 mg.
Who should be careful?
- Pregnant and breastfeeding women
- People with anxiety, panic attacks, insomnia, heart rhythm problems or uncontrolled high blood pressure
- People with acid reflux or stomach ulcers, since coffee increases stomach acid
- Children and teenagers
- People who take medicines that interact with caffeine; ask your pharmacist
- Caffeine can reduce iron absorption; drink coffee between meals, not with them, if you are low in iron
Signs you have had too much
Jitters, fast heartbeat, headaches, stomach upset, trouble sleeping and irritability. Cut down gradually to avoid withdrawal headaches.
Tips for healthier coffee
- Skip sugary syrups and heavy cream; they cancel out the benefits and add hundreds of calories.
- Stop drinking coffee 6 to 8 hours before bedtime; caffeine stays in your body for 5 to 6 hours or longer.
- Filtered coffee has fewer cholesterol-raising oils (cafestol) than unfiltered coffee such as French press, Turkish or boiled coffee, which matters if you drink many cups.
- Decaf keeps most antioxidants if you want to avoid caffeine.
- Add cinnamon or cardamom for flavor instead of sugar.
- Drink water too; coffee is mildly hydrating in normal amounts, not dehydrating.
Frequently asked questions
Does coffee stunt growth?
No evidence supports this, but children should avoid caffeine for other reasons.
Is it OK to drink coffee on an empty stomach?
For most people yes. If it causes stomach upset or reflux, drink it with food.
This is general information, not medical advice.
