10 Benefits of Black Tea According to Scientific Evidence

The benefits of black tea are largely due to its high antioxidant content. What are its applications? Find out more!
10 Benefits of Black Tea According to Scientific Evidence
Maria Patricia Pinero Corredor

Reviewed and approved by the nutritionist Maria Patricia Pinero Corredor.

Last update: 12 October, 2023

Over the years, the benefits of black tea have been documented in a wide variety of studies. Thanks to its abundant concentration of antioxidants – especially polyphenols – its intake might have positive effects on heart health. Also on metabolism, the digestive system, and the brain.

In particular, this variety of tea undergoes the process of withering, rolling, oxidizing, and drying the leaves of the Camellia sinensis plant. Its flavor is stronger than other teas from this species (such as green tea and oolong tea) and it also stands out for containing more caffeine (between 2% and 4%).

Although it’s not a first choice treatment against diseases, its anti-inflammatory, antioxidant, anti-diabetic, and anti-tumor properties help to maintain well-being. We’ll tell you in detail what it’s good for, how to consume it, and its possible contraindications and side effects.

10 benefits of black tea according to science

For several decades, the benefits of black tea have been a subject of interest for scientists. Its concentration of active compounds exhibits a wide variety of positive health effects.

It contains the following:

  • Phenolic acids
  • Minerals (calcium, chromium, magnesium, iron, potassium, and phosphorus)
  • Flavonoids (tearubigins, theaflavins, and catechins)
  • Amino acids (L-theanine)
  • Vitamins (A, C, and K)
  • Caffeine

Precisely because of this composition, several medicinal properties are attributed to it. To be more precise, it’s valued for its ability to fight inflammation. It can also increase alertness, inhibit the effects of oxidative stress, and prevent cell damage.

Is there evidence? We’ll discuss it below.

1. The benefits of black tea for heart health

Flavonoids, the main antioxidant compounds in black tea, have a positive impact on heart health. This is largely because they play a role in regulating inflammatory processes and preventing oxidative damage.

In this regard, a meta-analysis shared through Advances in Nutrition reported that for every cup of tea consumed daily, there’s a 4% decrease in death from heart disease and a 2% decrease in the risk of a heart attack.

It was also found to reduce the risk of stroke by 4% and the risk of death from all causes by 1.5%. In the end, it was determined that including it in a healthy dietary pattern can reduce the odds of cardiovascular disease and mortality among adults.

Another prospective study reported in the journal Heart revealed that daily tea consumption helps reduce the odds of ischemic heart disease and the risk of relevant cardiovascular events, such as heart attack.

Ischemic heart disease occurs when arteries become clogged and prevent – partially or completely – blood from being supplied to the heart muscle.

In turn, a randomized controlled trial published in Preventive Medicine concluded that black tea – ingested as part of a normal diet – helps to reduce independent cardiovascular risk factors, such as high glucose and alterations in the lipid profile.

Té negro reduce el riesgo cardiovascular.
The flavonoids in black tea could reduce overall cardiovascular risk when consumed frequently.

2. High cholesterol

Related to the previous point, note that black tea is linked to lower levels of “bad” cholesterol (LDL). The accumulation of this lipid in the arteries is related to heart failure and stroke.

A review of studies shared in Clinical Nutrition details that the intake of this tea helped to reduce the serum concentration of this type of cholesterol, especially in people at higher cardiovascular risk.

A study in rats reported in Lipids in Health and Disease found that theaflavin and terubigins – two flavonoids found in black tea – have the potential to address diseases associated with oxidative stress, such as hypercholesterolemia and hyperglycemia.

Even so, research results are mixed. In a randomized controlled trial, daily consumption of 5 cups of black tea per day did not significantly change the lipid profile in people with borderline hypercholesterolemia.

3. High blood pressure

Continuing with the benefits of black tea for cardiovascular health, we found interesting effects in lowering high blood pressure. In a meta-analysis reported in Food & Function, patients who took a black tea supplement had a significant reduction in systolic blood pressure compared to the control group.

Similar effects were seen in research shared in Complementary Therapies in Medicine , which revealed that regular tea intake helped lower systolic blood pressure by 4.81 mm Hg and diastolic blood pressure by 1.98 mm Hg in people with hypertension.

Because of its flavonoid content, black tea has benefits for people with hypertension. However, its intake should be within the framework of a healthy diet.

4. Intestinal health

Consuming black tea on a regular basis is also a way to take care of intestinal health. To be more precise – and as compiled in a review in Critical Reviews in Food Science and Nutrition –polyphenols help modulate the function of the intestinal barrier, in addition to supporting the balance of the microbiota.

Black tea (abundant in polyphenols) seems to promote the growth of good intestinal bacteria, while inhibiting the activity of harmful bacteria.

Another review of studies shared in the journal Nutrients highlights that black tea, as well as other tea varieties derived from the Camellia sinensis species, have prebiotic activity due to their contribution of polyphenols. In this way, it modulates the proportion of intestinal bacteria types and, incidentally, contributes to weight loss.

By modulating the function of the intestinal barrier and promoting the growth of healthy bacteria, black tea contributes to the strengthening of immune function. Still, larger studies are needed.

5. Concentration and cognitive performance

Black tea contains up to 4% caffeine and an amino acid called L-theanine. Both of these stimulating substances are associated with increased mental concentration and improved alertness. This explains why some people report feeling more energy after ingestion.

In this regard, research reported in the journal Nutrients found that L-theanine supplementation has the potential to stimulate brain function. In doing so, it improves focus and memory, among other cognitive abilities.

Meanwhile, a small study shared by Clinical Phytoscience determined that even a small amount of black tea helps improve cognitive processing. The beverage was linked to better mental task performance and increased concentration.

Persona con cansancio y sin concentración.
Some people use black tea infusions to improve their brain performance when tired. According to science, it might work.

6. High glucose

Black tea is not a first-line treatment for diabetes. However, including it as part of a good diet can bring benefits to patients with this disease.

Research shared in the Asia Pacific Journal of Clinical Nutrition linked its consumption to a decrease in postprandial blood glucose levels following sucrose intake. Specifically, 24 patients with and without prediabetes took a high-sugar drink followed by a low or high dose of black tea or a placebo.

In patients who ingested black tea – at both doses – a decrease in postprandial (after-meal) sugar levels was found compared to those who took a placebo. However, larger and more comprehensive studies are needed.

Another study links black tea to improved insulin response in people with obesity and insulin resistance. The publication, published in Nutrition & Metabolism , suggested that drinking black tea improves insulin sensitivity, especially after eating meals high in sugar.

It’s possible that black tea may benefit people with prediabetes and type 2 diabetes. However, it should be consumed without added sweeteners.

7. Bone health

A review reported in the journal Medicine concluded that tea intake helps reduce the risk of osteoporosis. These qualities are due to its high flavonoid content, which might decrease bone density loss and strengthen bones.

Another study in rats, shared by Frontiers in Physiology, suggests that theorugins and theaflavins in black tea play a beneficial role in controlling bone density loss by promoting osteoclastogenesis.

These benefits of black tea are particularly useful in menopausal and postmenopausal women, who are at increased risk for bone deterioration and osteoporosis.

8. Dental health

Catechins contained in Camellia sinensis leaves have bactericidal and bacteriostatic properties that act against dental plaque bacteria, such as Streptococcus mutans. A study shared in the Open Access Macedonian Journal of Medical Sciences states that a mouthwash based on tea (black and green to be more precise) can be used as an alternative to prevent the formation of dental caries.

Likewise, information from the American Society For Microbiology suggests that black tea and its components benefit oral health by interfering with the formation of bacterial plaque that causes cavities and periodontal disease.

In any case, it’s advisable to use it in moderation, since the tannins it contains have been related to the appearance of stains on teeth, similar to those caused by coffee.

9. Antitumor potential

Neither black tea nor other varieties of tea can prevent or cure cancer. Despite this, studies have determined that its components may delay the development of some forms of this disease and promote the death of malignant cells.

In a review shared by Advances in Nutrition, researchers observed that tea intake decreases the risk of oral cancer. To a lesser extent, it also appears to be associated with a lower risk of cancers – be it gastrointestinal, breast, ovarian, lung, or thyroid cancer.

Given the lack of larger, well-designed studies, for now, these findings are only a starting point for research into the effects of green tea on cancer. It should not be considered a treatment.

10. Weight loss

If weight loss is what you’re after, black tea can be a good addition to add to your diet. A study revealed by Food & Function found that drinking three cups of black tea a day for three months helped reduce waist circumference and body weight, compared to drinking a caffeinated control beverage.

One hypothesis suggests that these effects occur because of its high content of flavones, which act as antioxidants in the body. Still, we need more evidence.

In other research in the journal Molecules , experts observed that the polyphenols in black tea have an anti-obesity effect without apparent side reactions. In itself, they help to stimulate metabolism, as well as reduce oxidative stress and regulate energy intake.

Weight loss is one of the benefits of drinking black tea.
Black tea can only be an aid in a weight loss plan when accompanied by a healthy diet and lifestyle.

The risks and possible side effects of black tea consumption

For most healthy adults, moderate consumption of black tea is safe.

In general, two to three cups a day are tolerable. Problems begin to occur with more than four or five cups a day. This is largely due to its caffeine content.

In excess, this stimulant in black tea can trigger the following symptoms:

  • Anemia
  • Hypertension
  • Headaches
  • Nausea and vomiting
  • Restlessness and anxiety
  • Ringing in the ears
  • Increased urination
  • Difficulties to sleep
  • Nervousness and tremors
  • Breathing alteration

On the other hand, patients with anxiety disorders, bleeding disorders, a history of convulsions, irritable bowel syndrome, and hormonal problems shouldn’t drink it. Consult a doctor before trying this drink or supplements derived from it.

There’s a high risk of interactions between black tea and some medications. For safety reasons, doctors don’t recommend its simultaneous use with the following drugs:

  • Ephedrine
  • Clozapine
  • Estrogens
  • Carbamazepine
  • Antibiotics (quinolones)
  • Asthma medications
  • Phenylpropanolamine
  • Diuretic drugs
  • Anticoagulants
  • Contraceptives
  • Antidepressants

Whenever you are taking drugs or supplements (vitamins, herbs, dietary supplements, etc.), check with your doctor if there are risks of consuming them together with black tea.

Find out: Tea or Coffee After a Meal: Good or Bad?

The proper way to drink black tea for maximum benefits

In general, people drink black tea as a beverage, be it in a tea bag or in its dried form.

People usually drink it straight but some add other herbs or lemon. The proportions are usually one teaspoon or one sachet (5 grams) per cup of water (250 milliliters).

The drink is ready for consumption after letting the tea infuse for 10 minutes. Strain and sweeten to taste (and avoid sweeteners).

The benefits of black tea when consumed in moderation

Right now, black tea is one of the most consumed beverages along with coffee and green tea. It’s also an alternative to coffee and energy drinks. Although its potential benefits are still under investigation, its high antioxidant content could improve health.

In any case, it’s advisable to drink it in moderation, without exceeding three cups a day. If you’re under treatment with medication or if there is any underlying disease, consult your doctor before including this drink in your diet. Keep this in mind!

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

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This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.