Nervous system and brain
The amount of caffeine present in black tea, regulates the blood flow in the brain but doesn't over stimulate the heart. It helps the brain to retain more focus and concentrate on the task at hand. The amino acids found in black tea also help you relax. If you are a regular drinker of black tea, the levels of stress hormones in the body also decrease. It is researched that black tea is good for memory, it gives it a boost for a few hours and it has been said that it also acts as a protection against Parkinson's disease.
Black tea has been used in China for many years for gastric and intestinal illness. The tannins found in the tea have a therapeutic effect and aid in digestion. They cause the intestinal activity to reduce and have an anti-diarrhea effect.
The moderate amount of caffeine in black tea increases the metabolism and makes you more alert. The effect of tea is more subtle that cola or coffee, it doesn’t hit the body instantly like them. The presence of theophylline in the tea stimulates the heart, respiratory system and kidneys. This way, muscles and the cardio vascular system say healthy and a person remain energetic.
The presence of polyphenols in the tea help to stop the formation of some kinds of cancer including: lung, ovarian, prostate, bladder and colorectal. Some surveys show that black tea also aids in preventing prostate, breast and stomach cancer. TF-2 is a compound in black tea that causes these cells to die while not effecting the growth of other cells. Those people whose intake of cigarettes or other tobacco products is high should drink more black tea to prevent cancer.