Black Tea

How does Black Tea work?

Black tea contains 2% to 4% caffeine, which affects thinking and alertness, increases urine output, and may reduce the symptoms of Parkinson's disease. It also contains antioxidants and other substances that might help protect the heart and blood vessels.

Are there safety concerns?

Black tea is safe for most adults. Too much black tea, such as more than five cups per day, can cause side effects because of the caffeine. These side effects can range from mild to serious and include headache, nervousness, sleep problems, vomiting, diarrhea, irritability, irregular heartbeat, tremor, heartburn, dizziness, ringing in the ears, convulsions, and confusion.

If you are pregnant or breast-feeding, black tea in small amounts is probably not harmful. Do not drink more than 2 cups a day of black tea. This amount of tea provides about 200 mg of caffeine. Consuming more than this amount has been linked to an increased risk of miscarriage and other negative effects.

Caffeine is probably safe in children in amounts commonly found in foods.

Avoid consuming large amounts of black tea if:

• You are pregnant or breast-feeding.
• You have a heart condition (arrhythmia).
• You have severe anemia or a bleeding disorder.
• You have breast, uterine, or ovarian cancer.
• You have endometriosis or uterine fibroids.
• You have osteoporosis.
• You have high blood pressure. Small amounts of black tea taken regularly do not seem to raise blood pressure, but the caffeine in black tea can affect blood pressure in someone who consumes caffeinated drinks infrequently.