Black coffee contains antioxidants, boosts alertness, and has almost no calories. Too much caffeine can cause jitters and poor sleep.
Benefits
- Antioxidants (chlorogenic acids).
- Boosts alertness and focus.
- About 2 calories per cup.
- Linked to lower risk of type 2 diabetes, Parkinson’s and liver disease in studies.
Caffeine
An 8 ounce cup has about 95 mg.
Limit
The FDA says up to 400 mg a day is safe for most adults.
Downsides
Jitters, insomnia, reflux.
Pregnancy
Limit to 200 mg.
Nutrition and effects
A cup (8 oz, 240 ml) of black coffee has about 2 calories, 95 mg of caffeine, and small amounts of potassium, magnesium and niacin. Coffee contains chlorogenic acids and other polyphenols that have antioxidant activity.
- A 2017 umbrella review in the BMJ found that coffee drinking was associated with lower risk of all-cause mortality, cardiovascular disease and type 2 diabetes, with the largest benefit at 3 to 4 cups per day.
- Caffeine improves alertness and short-term performance.
- The FDA states that 400 mg of caffeine per day (about 4 cups) is generally safe for healthy adults.
Downsides and pregnancy
Too much caffeine can cause jitters, insomnia, rapid heartbeat and stomach upset. Coffee can worsen reflux in some. ACOG advises limiting caffeine to under 200 mg per day during pregnancy. Unfiltered coffee, like French press, raises LDL cholesterol more because it contains cafestol. People with anxiety, arrhythmia or high blood pressure should check with a doctor.
Nutrition and effects
Black coffee has about 2 calories per 8 ounce cup, with about 95 mg of caffeine. Observational studies link 3 to 4 cups a day with lower risk of type 2 diabetes, Parkinson’s disease and liver disease. The FDA says up to 400 mg of caffeine daily is generally safe.
Downsides and pregnancy
Coffee can cause jitters, insomnia and reflux. Pregnant women are advised to limit caffeine to 200 mg per day, per ACOG. Unfiltered coffee can raise LDL cholesterol.
Health associations
A 2017 BMJ umbrella review of meta analyses found that drinking 3 to 4 cups of coffee a day was associated with a lower risk of death and cardiovascular disease compared with no consumption. A 2021 Nutrients review linked coffee to lower type 2 diabetes risk. Chlorogenic acids give antioxidant activity. Black coffee has no sugar or fat.
Cautions
Coffee raises blood pressure briefly and interferes with iron absorption when taken with meals. Pregnant women should keep caffeine under 200 mg daily. Those with arrhythmia, anxiety or insomnia may need less. Withdrawal causes headaches within 12 to 24 hours. Unfiltered coffee such as French press contains cafestol that raises LDL.
Based on data from the BMJ and the FDA
