After water, tea is the second most consumed beverage in the world. All tea comes from the plant of Camellia sinensis, but various forms of extracting and processing the plant yield various types of tea.
Black tea leaves go through a process of wilting, bruising, rolling, and oxidation after harvesting.
If the leaves remain exposed to the air for a long time, oxidation occurs. Enzymes break down the chemicals in the leaves, creating their familiar scent and brown coloring.
The method for producing green tea is similar, but oxidation is not involved. Oxidation can bring nutritional benefits to black tea that are not present in green tea.
The nutrients in black tea, for instance, can minimize the risk of multiple cancers, protect the heart from atherosclerosis, and help maintain healthy blood pressure.
Learn more about the advantages of drinking black tea in this article, as well as the nutrients it offers and the potential risks.
Health benefits
Black tea accounted for about 84 percent of tea consumption in the U.S. in 2018, according to the United States Tea Association.
Black tea may have advantages comparable to green tea. However, several studies have looked specifically at black tea, and how the oxidation process can impact health.
Black tea as a source of antioxidants is a primary field of interest.
Antioxidants aid in fighting free radicals. Free radicals in the body are unstable molecules that arise from both natural processes and stresses on the environment.
The body can eliminate free radicals, but they can harm or alter cells in the body if too many build up.
These changes, such as atherosclerosis and certain cancers, may lead to the development of many diseases and conditions.
The elimination of free radicals can be assisted by antioxidants, and tea is one source of antioxidants. In fact, one study states that up to 30 percent of the dry weight of green and black tea consists of phenolic compounds that have antioxidant effects.
The antioxidants in black tea are, because of the oxidation phase, distinct from those in green tea. Green tea consists primarily of catechin. These are converted into thearubigin, theaflavin, and flavonol during oxidation.
These may give black tea different benefits to green tea.
What are antioxidants and how do we benefit from them?
Protecting against atherosclerosis
Atherosclerosis refers to a buildup of plaque in the walls of arteries. Coronary heart disease, stroke, and chronic kidney disease can contribute to this. Free radicals can contribute to this condition.
A 2004 hamster study indicated that drinking human-equivalent doses of black tea or green tea could avoid the development of atherosclerosis. In humans, further research is needed to confirm this.
One review indicates that it can help to protect against coronary heart disease by drinking three or more cups of tea a day.
It is important to remember, however, that black tea contains caffeine, and consuming more than three cups a day will add to the daily consumption of a person with a large amount of caffeine.
Researchers found data in 2013 to indicate that individuals who drank four or more cups of black tea a day had a lower risk of stroke.
Learn more about atherosclerosis here.
Lowering cancer risk
Findings cited by the National Cancer Institute (NCI) indicate that tea polyphenols can reduce tumor growth risk.
Black tea, in particular, can help reduce the risk of cancers of the skin, breast, lung, and prostate.
However, further studies are required to confirm whether consuming tea as part of the diet will help reduce the risk or not.
Blood Pressure Reduction
The results of a 2015 study indicated that diastolic and systolic blood pressure could be reduced by black tea.
The effect of a high fat meal on blood pressure also tended to be eliminated by drinking black tea.
Despite the caffeine content of the tea, the advantage remained. However, with only 19 participants, this was a small sample, so larger studies are required to validate these findings.
Find out more about foods that help to lower blood pressure in this post.
Protecting against diabetes
Some research has indicated that it may help to reduce the risk of diabetes by drinking tea.
In one study, over a span of 4 weeks, people with type 2 diabetes drank different quantities of black tea extract. The authors concluded that for individuals with this disease, daily consumption of black tea may have antioxidative and anti-inflammatory effects.
Benefits for other conditions
Black tea has also been found by researchers to help boost bone density, reduce the risk of rheumatoid arthritis, and protect against Parkinson’s disease.
To confirm these findings, however, further studies are needed.
Nutrition
The NCI note that tea contains:
- alkaloids, including caffeine, theophylline, and theobromine
- amino acids
- carbohydrates
- proteins
- chlorophyll
- fluoride
- aluminum
- minerals and trace elements
- volatile organic compounds, which contribute to its odor and taste
Due to its polyphenol content, black tea has an antioxidant impact. Polyphenols are chemical compounds that shield plants from ultraviolet radiation as well as harmful pathogens that cause disease.
One form of polyphenol consists of flavonoids. They are found in grapes, red wine, and various other foods.
The antioxidant effect of polyphenols can help to protect the body from disease-inducing changes.
What foods are strong antioxidant sources? Find out here.
Tips for serving
It can be a good way to have a daily caffeine boost by drinking black tea. The calorie content of tea is low, particularly when a person does not add sugar.
Without adding sugar or sweeteners, ways to change the flavor include:
- blending the tea with spices, such as cinnamon
- adding lemon juice
- adding mint
People can make use of it in cooking as well. For example, they can use it:
As a stock: Black tea can add a smoky taste to red meat or mushroom soups.
In poaching liquids: In black tea, poaching food infuses the aroma into the food. Poaching mushrooms in lapsang souchong black tea is one idea.
For cooking beans and grains: When cooking rice or beans, swapping water for tea adds a smoky nuance to their flavor.
In desserts: Infuse the flavor of tea into warm milk and add to puddings or custards. Or, infuse Earl Grey black tea into a chocolate mousse.
Risks
Drinking black tea can have some dangers. Those risks are addressed in more detail in the following pages.
Toxic elements
There are minerals in all brewed tea that, in abundance, may be poisonous.
In tea, lead and aluminum are present. These heavy metals can be harmful to humans in large doses. In certain teas, small traces of arsenic and cadmium may also be found, but not in dangerous amounts.
Black tea also has high levels of manganese. The body requires this mineral, but in excess, it can be harmful.
The longer tea brews, the higher the concentration of these toxic elements would be. You can reduce the risks by boiling tea for a maximum of 3 minutes.
There may also be traces of pesticides in the leaves, depending on where and how individuals cultivate the tea. This is another justification for individuals to reduce the amount of tea they eat each day.
Effects of caffeine
There is about 2-4 percent caffeine in black tea.
When drinking tea in large amounts, people who are sensitive to caffeine may experience insomnia, anxiety, irritability, or an upset stomach.
Also, consuming too much caffeine can lead to:
- cardiac arrhythmia, or an irregular heartbeat
- diarrhea and irritable bowel syndrome
- eye pressure, and possible glaucoma
- an increase or decrease in blood sugar
- an increase in blood pressure
- a loss of calcium through the urine, which could lead to weakened bones and possible osteoporosis
People who regularly drink tea and who experience some of the symptoms above should consider limiting their intake of tea. They should see a doctor if symptoms persist.
Anemia
Black tea contains tannins. One 2017 analysis found that foods high in tannins, such as tea, can be a good source of antioxidants, but they may also decrease the ability of the body to absorb iron.
For this reason, when taking iron supplements or eating an iron-rich meal, people with a history of iron deficiency should avoid drinking tea.
They should also leave an hour between eating and drinking black tea.
Learn more about iron deficiency anemia here.
Interactions with drugs and supplements
A number of different medications and supplements can interact with black tea and the caffeine it contains.
Such drugs include, but are not limited to:
Adenosine: Before a heart stress test, doctors offer this drug.
Antibiotics: Certain forms of antibiotics influence the way caffeine breaks down in the body.
Carbamazepine (Tegretol): Caffeine can decrease the efficacy of this drug in seizure protection.
Ephedrine: This is a stimulant, as is caffeine. Therefore, taking them together could cause side effects.
People who use medicines should talk to their doctor about their caffeine intake through tea or coffee. It may have an impact on how their medications work and their risk of adverse effects.
Composition
Iced teas and ready-to-drink teas, since the composition is different, can be less nutritious than plain black tea. Sugar and other ingredients can be contained in instant and flavored teas.
Adding sugar, milk, cream, and syrups to tea tends to increase the calorie content and may decrease its health benefits.
Summary
Black tea is a common drink around the world, and there may be some health benefits to it. Often, it is low in calories.
The potential risks, such as high caffeine and sugar intake, should be taken into account by people who drink a lot of tea, particularly with added milk, sweeteners, or syrup.
If a high consumption of black tea is likely to interfere with any drugs they are taking or affect other aspects of their health, they may also wish to ask their doctor.
Sources
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(LINK) - Grassi, D., et al. (2015). Black tea lowers blood pressure and wave reflections in fasted and postprandial conditions in hypertensive patients: A randomized study [Abstract].
(LINK) - Khan, N., & Mukhtar, H. (2013). Tea and health: Studies in humans.
(LINK) - Larsson, S. C., et al. (2013). Black tea consumption and risk of stroke in women and men [Abstract].
(LINK) - Lobo, V., et al. (2010). Free radicals, antioxidants and functional foods: Impact on human health.
(LINK) - Schwalfenberg, G., et al. (2013). The benefits and risks of consuming brewed tea: Beware of toxic element contamination.
(LINK) - What are the health benefits of black tea? (LINK)
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(LINK) - Tea fact sheet. (2019).
(LINK) - Vinson, J. A., et al. (2004). Green and black teas inhibit atherosclerosis by lipid, antioxidant, and fibrinolytic mechanisms [Abstract].
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