**5. Black tea benefits**

The healthiest tea for you is the one you will want to drink every day. By that definition, if you live in the West, the tea that is the healthiest for you is probably black tea. Over 90% of all tea sold in the West is black tea (or red tea, as it is known in the East).

Like green tea, oolong tea and white tea, black tea is made from leaves of the *Camellia sinensis* plant, so it shares many tea health benefits with other tea types. However, black tea is unique, and it is known to be especially beneficial for certain health purposes [8, 25].

The major health benefits of black tea include its nutritional value, anti-cancer benefits, digestive benefits, beneficial effects on skin and hair health, and much more. Grab a cup of tea (preferably organic tea) and learn more.

Black tea also contains catechins (the powerful antioxidants in tea that fight cancer-causing cells and help prevent heart disease), tannins (the naturally occurring chemical compounds that give black tea and red wine their astringency), guanine (a natural stimulant) and xanthine (another natural stimulant, similar to caffeine).

The many antioxidants and polyphenols in black tea are associated with a number of health benefits. Specifically, black tea contains complex flavonoids, which are polyphenols that aid in disease prevention. A single cup of black tea contains an average of 200 mg of flavonoids. Many doctors now recommend getting 600 mg of flavonoids per day for a range of health benefits. The flavonoid polyphenols in black tea known as thearubigin and theaflavin act as especially powerful antioxidants. Interestingly, these two flavonoids are more concentrated in black tea than in green tea [22, 23, 27].

#### **5.1 Black tea and cardiovascular health**

Black tea is abundant in antioxidants, such as flavonoids. These antioxidants have been demonstrated to lower the risk of heart disease. They do this by preventing the oxidation of LDL cholesterol and preventing damage in both the bloodstream and at artery walls. Additionally, black tea flavonoids can both improve coronary vasodilation and reduce clots, and its manganese may reduce the risk of coronary heart disease by helping cardiac muscle function. Studies have shown that as few as three cups of tea per day can improve heart health [25].

#### **5.2 Cancer prevention**

Perhaps the most-studied tea health benefit is its anti-cancer benefit. While most of the study has been on green tea, there is a growing body of evidence that black tea also plays a role in cancer prevention [25].

*Health Benefits of Aqueous Extract of Black and Green Tea Leaves DOI: http://dx.doi.org/10.5772/intechopen.91636*

It appears that the polyphenols in tea help prevent the formation of potential carcinogens in the body. This is particularly true with certain types of cancer, such as ovarian cancer, lung cancer, prostate cancer, colorectal cancer, and bladder cancer. Some studies also show that black tea may help prevent stomach cancer, prostate cancer, breast cancer and oral cancers (especially for those who use tobacco products) [25–28].

The mechanism with which black tea prevents cancer is an interesting one. Black tea contains a compound called TF-2. This chemical causes apoptosis ("programmed death") of cancer cells without harming normal, healthy cells. This helps to stop cancer growth before it even becomes noticeable, and may help in cases where cancer has already been diagnosed. Additionally, black tea also prevents cancer by inhibiting the formation and growth of malignant tumors [25].

#### **5.3 Black tea benefits the immune system**

The tannins in black tea do not just give it its characteristic taste. Several studies have shown that tannins help fight viruses such as influenza ("the flu"), dysentery, and hepatitis. Black tea also contains alkylamine antigens, which help boost immune response [25].

#### **5.4 Black tea and oral health**

There are many folk tales about tea, freshening the breath and cleansing the mouth. It turns out that they are true. Research has found that black tea may reduce oral cancers. Additionally, tea's polyphenols and tannin's kill and prevent the bacteria that cause tooth decay, and to drastically reduce the oral bacteria that cause bad breath [25].

#### **5.5 Black tea's digestive benefits**

The tannin in tea in general (and black tea in particular—it has more of them than other tea types) offer digestive benefits. They soothe gastric and intestinal illnesses, generally aid in digestion and decrease intestinal activity (making them useful for those with diarrhea) [24, 25].

#### **5.6 Black tea and hair health**

Although it may seem rather vain compared to some of the other more lifealtering health benefits of black tea, black tea is fantastic for your hair.

The high levels of antioxidants and caffeine in black tea both benefit hair health. The caffeine decreases a hormone that causes hair loss (known as DHT or dihydrotestosterone), while the antioxidants promote healthy hair growth. However, excess caffeine may stunt hair growth, so be careful not to overdo it. Black tea can also add shine, luster, and darkness to your hair if you incorporate it into your hair care regimen [25].

#### **5.7 Bone and connective tissue benefits of black tea**

If you drink tea regularly, you are more likely to have stronger bones and connective tissue than someone who does not drink tea regularly. Scientists believe this may be due to tea's phytochemicals [25].

#### **5.8 The effect of black tea on brain (and nervous system)**

The caffeine in black tea has been shown to improve mental focus and concentration by promoting blood flow in the brain. Unlike drinks with higher levels of caffeine and other stimulants (i.e., coffee and energy drinks), the caffeine in black tea is less likely to over-stimulate the heart and cause other unpleasant side effects.

Caffeine aside, studies show that L-theanine (an amino acid found in black tea) balances the effects of caffeine in a unique way, helping you concentrate more fully on tasks and act in a focused but relaxed manner. Furthermore, studies show that 1 month of four cups of black tea a day reduces levels of the stress hormone cortisol enough to boost your memory function, and some studies suggest that regular black tea consumption may prevent Parkinson's disease [8].
