Black tea is known to be strong in flavour and it contains more caffeine than other teas, though less caffeine than coffee or energy drinks. It is made from the leaves of a bush called Camellia sinensis. Black tea also contains stimulants and antioxidants.

Healthline states that black tea is one of the most consumed beverages in the world, aside from water, and offers a variety of health benefits because it contains antioxidants and compounds that can help lower inflammation in the body.

Emmy Ntamanga, a Kigali-based nutrition consultant, says that black tea is known to protect against diabetes, noting that research suggests so. 

He adds that it’s evident that black tea may reduce the risk of cancer based on recent studies conducted by the National Cancer Institute (NCI) which proposes that the polyphenols present in black teas may decrease the risk of tumour growth, and to be specific, black teas reduce the risk of skin, breast, lung, and prostate cancers.

Ntamanga, however, notes that black tea must not be considered as an alternative treatment for cancer. 

"People who consume black tea can help get rid of and lessen damage in the body, which after sometime may help lower the risk of chronic diseases. The main sources of antioxidants in black tea and a blend of polyphenols like catechins, theaflavins, and thearubigins, promote general health,” he says. 

Ntamanga explains that black tea contains caffeine and a type of amino acid called the L-theanine—which can assist in improving alertness and focus.

He says that some studies show that drinks containing a combination of L-theanine and caffeine increase the alpha activity brain and have significant results on focus and alertness.

Black tea is known to be effective for oral health, for instance, research funded by the Tea Trade Health Research Association indicated that black tea reduced plaque formation and restricted bacterial growth. Black tea also reduces cavities and tooth decay and the polyphenols present in black tea also suppress cavities—bacteria that hinder the growth of bacterial enzymes that form the sticky-like material that binds plaque to teeth.

Scientists state that black tea contains antioxidants known as flavonoids, which are beneficial to heart health. Consuming it on a regular basis may help reduce many risk factors for heart disease, including high blood pressure, high cholesterol, elevated triglyceride levels and obesity.

Ntamanga explains that black tea is rich in numerous vitamins and minerals that are good for the skin, and these include; zinc, magnesium, and potassium, all of which can help to protect and renew the skin. In addition to these beneficial compounds, consuming tea can help you stay hydrated—a thing that may assist the skin to look healthy, fresh, and flourished.

He also adds that black tea can calm headaches due to its average caffeine content. In addition, caffeine present in black tea can also help increase the efficacy of pain medication such as aspirin and ibuprofen. However, he says that tea shouldn’t be consumed in excess as it contains caffeine which can cause headaches. 

Health experts note that black tea has also been suggested for tea drinkers as it strengthens bones and lowers prospects of developing arthritis due to the phytochemicals found in tea.

According to WebMD, drinking large amounts of black tea, more than four or five cups a day, may cause health problems. That’s mostly because of caffeine-related side effects and some of these may include; anxiety and difficulty sleeping, faster breathing, headache, increased urination, irregular heartbeat, nausea and vomiting, nervousness and restlessness, ringing in the ears, tremors, anaemia and high blood pressure. 

"Black tea or black tea supplements may interfere with other medicines and supplements you are taking. Some medicines can also cause caffeine to stay in your body longer than usual. Talk to your doctor to find out if any medicines you are taking may have this effect. The caffeine in black tea may also interfere with certain blood tests. Always tell your doctor about any supplements you are taking, including natural ones and those bought without a prescription,” the site states.