“Tea plant, Camellia sinensis, has been cultivated for thousands of years and its leaves have been used for medicinal purposes. Tea is used as a popular beverage worldwide and its ingredients are now finding medicinal benefits,” the researchers say.

Black tea is a product made from the Camellia sinensis plant. The aged leaves and stems are used to make medicine. Green tea, which is made from fresh leaves of the same plant, has some different properties.

The study states that encouraging data showing cancer-preventive effects of green tea from cell-culture, animal and human studies have emerged.

“Evidence is accumulating that black tea may have similar beneficial effects,” they aver.

Tea consumption has also been shown to be useful for prevention of many debilitating human diseases that include maintenance of cardiovascular and metabolic health, even as various studies suggest that polyphenolic compounds present in green and black tea are associated with beneficial effects in prevention of cardiovascular diseases, particularly of atherosclerosis and coronary heart disease.

In addition, anti-aging, anti-diabetic and many other health beneficial effects associated with tea consumption are described.

“Evidence is accumulating that catechins and theaflavins, which are the main polyphenolic compounds of green and black tea, respectively, are responsible for most of the physiological effects of tea,” the study says; even as it describes the evidences from clinical and epidemiological studies in the prevention of chronic diseases like cancer and cardiovascular diseases and general health promotion associated with tea consumption.

However, experts at online portal, WebMD, warn that black tea contains between two and four percent caffeine, which affects thinking and alertness, and increases urine output, among others.

The portal also warns that high amounts of black tea can cause side effects due to the caffeine in it. “These side effects can range from mild to serious and include headache, nervousness, sleep problems, vomiting, diarrhoea, irritability, irregular heartbeat, tremor, heartburn, dizziness, ringing in the ears, convulsions, and confusion,” the portal claims.

In fact, WebMD says that more evidence is needed to rate the effectiveness of black tea for some of the uses to which it is put.

Speaking with PUNCH HealthWise, Dr. Oloyede said, “From available evidence, it has been found that every person should not take more than three to five cups of black tea daily, otherwise, the side effects of caffeine will be seen in that person.”

The nutrition expert noted that while black tea and coffee contain caffeine, the caffeine in black tea is less.

“Coffee contains high caffeine and because of this, it usually provides a quick energy boost.

“Apart from the fact that black tea contains caffeine, it also contains theanine, which causes a slow and continuous release of energy,” Oloyede explained.

He advised that people with high sensitivity to caffeine could take black tea. “if you have a high sensitivity to caffeine, then you should go for black tea,” he said.

Speaking on the effects of adding milk or sugar to black tea, Oloyede said, “The maximum effect of black tea is felt when taken as produced;” warning that adding other things does not diminish what is found in black tea, “but the issue is that the quantity you are taking is diluted by what you have added to the tea.”

Rating the ‘safety’ of black tea, WebMD says, “When taken by mouth, drinking moderate amounts of black tea is likely safe for most adults.

“Drinking too much black tea, such as more than five cups per day, is possibly unsafe,” because, “High amounts of black tea can cause side effects due to the caffeine in black tea.

“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.

“Also, people who drink black tea or other caffeinated beverages all the time, especially in large amounts, can develop psychological dependence.”

The portal also warns that drinking very high amounts of black tea containing more than 10 grams of caffeine is likely unsafe, warning that “Doses of black tea this high might cause death or other severe side effects.”

source: Punch