Over the years, the benefits of black tea have been documented in a wide variety of studies. Due to its high concentration of antioxidants—especially polyphenols—its consumption has been linked to positive effects on heart health, metabolism, the digestive system, and the brain.
Specifically, this variety of tea is obtained through a process of withering, rolling, oxidation, and drying the leaves of the Camellia sinensis plant. Its flavor is stronger than that of other teas obtained from this species (such as green tea and oolong tea ), and it is also notable for containing more caffeine (between 2% and 4%).
While it’s not a first-line treatment for diseases, its anti-inflammatory, antioxidant, antidiabetic, and antitumor properties help maintain well-being. We’ll tell you in detail what it’s recommended for, how to consume it, and what its possible contraindications and side effects are.
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 has exhibited a wide variety of positive health effects.
It has been determined that it contains the following:
- Phenolic acids.
- Minerals (calcium, chromium, magnesium, iron, potassium, or phosphorus).
- Flavonoids (thearubigins, theaflavins, and catechins).
- Amino acids (L-theanine).
- Vitamins (A, C, and K).
- Caffeine.
Precisely because of this composition, it is attributed with several medicinal properties. More specifically, it is valued for its ability to combat inflammation, increase alertness, inhibit the effects of oxidative stress, and prevent cell damage.
1. Heart health
Flavonoids, the main antioxidant compounds in black tea, have a positive impact on heart health. This is largely due to their 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 is a 4% decrease in death from heart disease and a 2% decrease in the risk of heart attack.
It was also observed that it reduces the risk of stroke by 4% and the risk of death from all causes by 1.5%. Ultimately, it was determined that including it in a healthy dietary pattern can reduce the likelihood of cardiovascular disease and mortality among adults.
Another prospective study published in the journal Heart revealed that daily tea consumption helps reduce the likelihood of ischemic heart disease and the risk of relevant cardiovascular events, such as a heart attack.
In turn, a randomized controlled trial published in Preventive Medicine concluded that black tea ingested within a normal diet helps to reduce independent cardiovascular risk factors, such as high glucose and alterations in the lipid profile.
2. High cholesterol
Related to the previous point, it’s worth noting that black tea is linked to lower levels of bad cholesterol (LDL). The accumulation of this lipid in the arteries is associated with heart failure and stroke.
A review of studies shared in Clinical Nutrition details that the intake of this tea helped to decrease the serum concentration of this type of cholesterol, especially in people with a higher cardiovascular risk.
Meanwhile, a study in rats published in Lipids in Health and Disease details that theaflavin and terubigins —two flavonoids present 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 one randomized controlled trial, daily consumption of 5 cups of black tea 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 find interesting effects in lowering high blood pressure. In a meta-analysis published in Food & Function, patients who took a black tea supplement showed a significant reduction in systolic blood pressure compared to the control group.
Similar effects were observed in research shared in Complementary Therapies in Medicine, which revealed that regular tea intake helped to lower systolic blood pressure by 4.81 mm Hg and diastolic blood pressure by 1.98 mm Hg in people with hypertension.
4. Gut health
Drinking black tea regularly is also a way to support gut health. More specifically—and according to a review in Critical Reviews in Food Science and Nutrition —polyphenols help modulate the function of the intestinal barrier, in addition to promoting a balanced gut microbiota.
Another review of studies published in the journal Nutrients highlights that black tea, like other tea varieties derived from the Camellia sinensis species, has prebiotic activity due to its polyphenol content. In this way, it modulates the proportion of different types of gut bacteria and, incidentally, aids in weight loss.
5. Concentration and cognitive performance
Black tea contains up to 4% caffeine and an amino acid called L-theanine. Both of these stimulants are linked to increased mental focus and improved alertness. This explains why some people report feeling more energetic after drinking it.
A study published in the journal Nutrients found that L-theanine supplementation has the potential to stimulate brain function. This improves focus and memory, among other cognitive abilities.
Meanwhile, a small study published in Clinical Phytoscience determined that even a small amount of black tea helps improve cognitive processing. The beverage was linked to better performance on mental tasks and increased concentration.
6. High glucose
Black tea is not a first-line treatment for diabetes. However, including it as part of a healthy diet may offer benefits to patients with this disease.
A study published in the Asia Pacific Journal of Clinical Nutrition linked sugar consumption to a decrease in postprandial blood glucose levels after sucrose intake. Specifically, 24 patients with and without prediabetes consumed a high-sugar beverage followed by a low or high dose of black tea or a placebo.
Patients who consumed black tea—at both doses—showed a decrease in postprandial (after-meal) blood sugar levels 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, released in Nutrition & Metabolism, suggested that drinking black tea improves insulin sensitivity, especially after consuming sugary meals.
7. Bone health
A review published in the journal Medicine concluded that tea consumption helps reduce the risk of osteoporosis. These benefits are attributed to its high flavonoid content, which is linked to decreased bone density loss and stronger bones.
Another study in rats, shared by Frontiers in Physiology, suggests that theorugin and theaflavin from black tea play a beneficial role in controlling bone density loss by promoting osteoclastogenesis.
8. Dental health
The catechins contained in Camellia sinensis leaves have bactericidal and bacteriostatic properties that act against bacteria in dental plaque, such as Streptococcus mutans. A study published in the Open Access Macedonian Journal of Medical Sciences suggests that a tea-based mouthwash (specifically black and green tea) can be used as an alternative to prevent tooth decay.
Furthermore, 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.
However, it is advisable to use it in moderation, since the tannins it contains have been linked to the appearance of stains on the teeth, similar to those caused by coffee.
9. Antitumor potential
Neither black tea nor other varieties of tea can prevent or cure cancer. However, studies have determined that their components may slow the development of some forms of the disease and promote the death of malignant cells.
In a review published in Advances in Nutrition, researchers observed that tea consumption decreases the risk of oral cancer. To a lesser extent, it also appears to be associated with a lower risk of gastrointestinal, breast, ovarian, lung, and thyroid cancers.
10. Weight loss
If weight loss is your goal, black tea can be a good addition to your diet. A study published in Food & Function found that drinking three cups of black tea daily for three months helped reduce waist circumference and body weight compared to drinking a caffeinated control beverage.
In another study published in the journal Molecules, experts observed that the polyphenols in black tea have an anti-obesity effect without apparent side effects. They help stimulate metabolism, reduce oxidative stress, and regulate energy intake.