Tea Caffeine Levels

(Graphic: Volume calculated in coffee cup sized vessles.)

In general, a tea has caffeine levels of 2.5–4.5%. Since caffeine is a water-soluble compound, approximately 80% of it is extracted during normal brewing. While the concentration of caffeine in tea can vary considerably depending on type and strength of brew a 170 mL (a regular teacup size—about 6oz) serving of tea contains on average 34 mg of caffeine.

For most people intakes of up to 400-450 mg of caffeine per day do not increase the risk of heart disease, hypertension or diverse effects on pregnancy or the fetus. This amount is equivalent to 10- 12 cups of tea per day.

It is estimated that coffee is a major source (60%) of caffeine for Americans, 30% comes from tea and the remaining 10% comes from cola drinks, chocolate and drugs.

Most epidemiological studies have investigated coffee consumption as a primary source of caffeine. Therefore, to determine the health effects of caffeine with respect to tea consumption, data from existing studies must be extrapolated.

While concerns of them raised regarding the possible effect of caffeine consumption in the development of cardiovascular disease and cancer, numerous epidemiological studies have failed to consistently implicate caffeine is a risk factor for these diseases.

Existing scientific data also indicates that chronic ingestion of caffeine, in amounts found in coffee or tea, has no negative effects on the central nervous system or urinary tract or renal function.

The general consensus is that consumption of methylxanthines (caffeine is a trimethylxanthine) from tea has no significant negative health implications. It is recognized, however, that certain individuals are sensitive to this chemical compound and could experience some adverse side effects. For such people, decaffeinated teas, now widely available, provide a suitable alternative.