Black tea health benefits: widely accepted as being good for you.
As far back as the 3rd century BC the Chinese recommended tea to improve concentration and alertness. They referred to it as the ‘elixir of life’. Thomas Garraway, London’s first tea merchant, advertised it as a cure-all. Black tea health benefits are now widely recognised amongst health professionals.
Caffeine in tea
Tea does contains caffeine, a stimulant, but at lower levels than coffee. An average cup contains the following levels:
- White tea contains 6.3 mg caffeine per 100ml.
- Green tea contains 10.6 mg caffeine per 100ml.
- Oolong contains 11.0 mg of caffeine per 100ml.
- Black tea contains 19.9 mg of caffeine per 100ml.
These caffeine levels in tea compares with these other beverages as follows:
- Hot chocolate containing around 2.1 mg of caffeine per 100ml.
- Instant coffee containing around 24.1 mg of caffeine per 100ml.
- Ground coffee containing around 45.4 mg of caffeine per 100ml.
- Espresso coffee containing around 173.6 mg of caffeine per 100ml.
Source: Caffeine Informer
The polyphenols contained in tea slow the absorption of caffeine by the body, making tea much more refreshing and revitalising than coffee. The caffeine levels in the blood stream caused by coffee tend to cause a sharp peak. Unlike black (oxidised) teas, green teas have very low caffeine levels. See our Green Tea section.
Theanine in tea
Tea also contains an amino acid called theanine which aids relaxation and helps overcome anxiety. This is present in high concentrations in some Japanese green teas, such as Sencha Gyokuro, which are grown partially in the shade and therefore have a high concentration of chlorophyll.
Combats Cardio-vascular Disease
Drinking tea can help reduce the risk of heart disease, stroke and thrombosis. This is due to the cholesterol inhibiting effects of the antioxidants present in tea. A cup of tea typically contains three times as many antioxidants as an average apple. In five research papers summarised in 2007 four of five studies found significant correlations between tea consumption and a lower risk of coronary heart disease and hypertension.
Tea Reduces the Risk of Diabetes
Diabetes is a condition of disordered glucose metabolism linked with obesity. The main source of glucose in the body comes from the digestion and hydrolysis of dietary carbohydrates, i.e. starches and sugars. Two studies demonstrate that extracts from black tea leaves can help to modulate levels of the enzymes responsible for glucose, thereby reducing its production.
Tea Reduces Cholesterol Levels
Ten studies looking at tea drinking and serum cholesterol levels found that drinking black tea significantly reduced LDL cholesterol levels, with the effect being higher amongst subjects with high cardiovascular risk.
Tea Combats the effects of Alzheimer’s and Parkinson’s Diseases
Regular consumption has been shown to act as a neuro-protective agent in combating the onset of Alzheimer’s and Parkinson’s Diseases.
Tea Combats Cancer
Consumption may, according to research, reduce the risk of various cancers, especially lung, colon and skin cancers. This is due to the natural antioxidants present in both green and black tea. These antioxidants combat oxidation caused by free radicals. Research has also shown that green tea may lower the risk of breast cancer.
Tea’s Anti-viral and Anti-bacterial Properties
As with all fresh fruit and vegetables tea contains antioxidants. However, due to its constituent polyphenol content, the antioxidant levels in green tea have been reported to be one hundred times more effective than vitamin C and twenty-five times better than vitamin E at protecting the immune system. Tea is considered to be a natural antiseptic.
Tea Combats the Natural Effect of Ageing
Antioxidants are particularly valuable in combating the effects of free radicals which are naturally occurring yet toxic molecules. They damage healthy cells and affect their ability to function normally. One group of antioxidants is known as polyphenols and around half of these are flavanoids. Tea is said to have the highest flavonoid content of all plants at 15% dry weight and accounts for 80% of the UK population’s dietary intake of flavonoids.
Flavanoids are divided into flavonols and flavanols. Tea is very rich in the latter which are especially valuable as they contain catechins which are very effective at combating free radicals. Green tea contains an abundance of especially bioactive catechins.
Live longer! A recent study published in the American Journal of Nutrition found that drinking two cups of tea a day is associated with a 40% reduction in risk of mortality from all causes.
Additional Health Benefits of Tea
- Tea taken without milk or sugar has no calories.
- Tea is rich in vitamins B1, B2 and C.
- Tea is good for dental hygiene. As a natural source of fluoride, tea helps strengthen teeth and prevent tooth and gum decay. Only 11% of water supply in the UK has fluoride added to it.
- Tea reduces dental decay. The polyphenol compounds have been demonstrated to prevent Streptococcus mutans, the bacteria that causes dental cavities, from adhering to our teeth.
- Tea supplies us with calcium. Four cups each day provides around 17% of our recommended daily calcium needs. This helps give us strong bones and teeth. Five studies summarised in 2003 concluded that consuming over four cups per day improved bone density in older women.
- Tea contains 22% of our recommended daily amount (RDA) of zinc.
It should be stressed that as a natural product there are many variations in the relative concentrations of complex chemical compounds naturally found within tea. These will depend on the exact variety, where it is grown, the sunlight received during growth, whether the leaves are manufactured as green or black, the amount used in brewing and the length of time it is infused. Further scientific research will need to address these issues for more conclusive results on some of the health benefits of tea. Much of the latest research into the health properties of tea is summarised by the Tea Council.
See our page on Green tea health benefits.