Tea is one of the most popular beverages globally, with black tea representing approximately 80% of consumption worldwide. The leaves of the Camellia sinensis plant are crushed, exposed to air, and dried to make black tea. This converts the green tea catechins into more complex theaflavins and thearubigins, giving black tea its characteristic dark color and unique flavor profile.
The diverse bioactive components of black tea include theaflavins like theaflavin-3-gallate, thearubigins, catechins like epigallocatechin gallate (EGCG), flavonoids, alkaloids like caffeine, amino acids like theanine, and more.
Green tea has catechins, while black tea has theaflavins and thearubigins formed during fermentation.
Antioxidant Properties
A growing body of research suggests regular black tea consumption may protect against various diseases and chronic conditions. The foremost bioactivity of black tea polyphenols is antioxidant capacity. Theaflavins are more potent antioxidants than catechins, effectively scavenging free radicals and chelating transition metals involved in oxidative reactions.
Anti-Inflammatory Effects
Black tea demonstrates anti-inflammatory properties by suppressing inflammatory cytokines like IL-1β, IL-6, IL-8, TNF-α and boosting anti-inflammatory IL-10 production. However, the low bioavailability of black tea polyphenols likely limits anti-inflammatory effects in humans. Still, black tea polyphenols may help protect against dental caries through antibacterial mechanisms.
Anticancer Properties
Numerous studies reveal black tea polyphenols inhibit proliferation, metastasis, mutagenesis, angiogenesis and spur apoptosis in cancer cells. While cell culture and animal research are promising, epidemiological data fails to clearly demonstrate black tea consumption significantly reduces cancer risk in humans.
Cardiovascular Benefits
Black tea polyphenols can reduce the risk of cardiovascular disease. They do this by improving factors such as high cholesterol, inflammation, and problems with blood vessels. This is especially beneficial for patients with existing heart problems. However, large cohort studies do not find a significant correlation between black tea intake and reduced CVD mortality.
Inconsistent Results in Human Trials
The inconsistent results in human trials may be caused by several factors. One possible reason is not enough intake for a therapeutic effect. Another reason could be the low absorption of black tea polyphenols. Additionally, differences in metabolism based on genetics and culture may also contribute to inconsistent results.
Bioavailability studies show low plasma levels of black tea polyphenols and metabolites post-ingestion. However, digestion may enhance bioavailability by converting thearubigins to the smaller and more absorbable theaflavins.
Conclusion
In summary, black tea exhibits diverse bioactivity in vitro and shows promise for improving human health. More research is needed to prove that drinking black tea regularly is good for your health. This is because previous studies have had mixed results, and the body doesn’t absorb all the beneficial compounds in tea.
Video
Black Tea: Its Most Powerful Benefit, Dr. Berg
Scientific Studies
An Update on the Health Benefits of Green Tea
The Benefits of Green Tea – A Review
For an overview of the different types of tea, please follow this link.
For the health benefits of other teas, please follow these links: