Most of us have heard about the health benefits of tea, and this has been confirmed by numerous scientific studies. Since the mid-1980s, scientists have accumulated over 8,000 publications on the health benefits of tea. In 2010, over a thousand papers related to tea and health were published worldwide. Today, with advances in technology, more and more scientific reports are confirming the anti-cancer properties of tea.
Among various types of loose leaf teas such as loose leaf green tea, loose leaf black tea, loose leaf oolong tea, loose leaf dark tea and loose leaf white tea, loose leaf oolong tea stands out for its anti-cancer benefits. Let's delve into the details.
Research Has Shown That Oolong Tea Has a Preventive and Therapeutic Effect on Several Types of Cancer.
1 Oolong Tea in the Prevention of Esophageal Cancer
In 1998, researchers at the Toxicology and Chemistry Research Department of the Institute of Nutrition and Food Hygiene, Chinese Academy of Preventive Medicine, conducted experiments on the inhibitory effects of tea in animal models. They fed rats with five types of tea, including Anxi TieGuanyin, and exposed them to a carcinogen, methyl-nitroso-ketone. After three months, the rats that did not consume tea had an esophageal cancer incidence rate of 90% and an average tumor count of 5.2. In contrast, the rats that consumed tea had an incidence rate of 42-67% and an average tumor count of 2.2-3. Among the teas, Anxi TieGuanYin exhibited the most potent anti-cancer effects. In another experiment using sodium nitrite and methyl-nitroso-ketone as carcinogenic precursors, no esophageal cancer occurred in the tea-consuming group, while the non-tea-consuming group had a 100% incidence rate.
An epidemiological study in Taiwan also revealed a significant inverse relationship between oolong tea consumption and the risk of esophageal squamous cell carcinoma (ESCC).
2 Oolong Tea in the Prevention of Stomach Cancer
A large-scale, community-based prospective cohort study in Japan explored the potential relationship between tea consumption and stomach cancer risk among Japanese men and women. The study involved 63,848 participants (26,025 men and 37,823 women) aged 40-79 years, with a median follow-up period of 13.3 years. The main outcome variable was the risk of stomach cancer determined by tea consumption frequency. The results showed that tea consumption had no association with the risk of stomach cancer in both men and women, but oolong tea was found to have a certain inhibitory effect on the carcinogenesis of human stomach cancer cells.
3 Oolong Tea in the Prevention of Breast Cancer
In 2018, research by Shi H and colleagues discovered that oolong tea induces DNA damage and fragmentation, inhibiting the growth, proliferation, and tumorigenesis of breast cancer cells. It is considered a promising chemopreventive agent for breast cancer.
4 Oolong Tea in the Prevention of Colorectal Tumors
A study by Niho and colleagues in 2006 found that a flavonoid derivative in oolong tea called tea flavonoid glycoside, when continuously fed to Min mice lacking the Apc gene and rats with azoxymethane-induced colon tumors for 14 weeks, had strong potential in inhibiting the development of precancerous lesions in the colon.
In addition to these findings, several studies suggest that oolong tea also has certain preventive and therapeutic effects on uterine cancer, skin cancer, lung cancer, prostate cancer, liver cancer, and kidney cancer.
Why Does Oolong Tea Have Anti-Cancer Health Benefits?
The main production steps of loose leaf oolong tea include withering, shaking, roasting, rolling, and drying. It is the unique processing method of oolong tea that imparts it with a rich profile of bioactive compounds, including tea polyphenols (catechins), tea pigments (catechins, theaflavins), theanine, caffeine, tea polysaccharides, vitamins, and aromatic substances.
Among these compounds, the primary substance EGCG (Epigallocatechin gallate) , which is a type of tea polyphenols, plays a significant role in cancer prevention and treatment. Firstly, EGCG exhibits antioxidant activity. Secondly, EGCG inhibits the activity of enzymes that promote tumor development, including protein kinase C, ornithine decarboxylase, cyclooxygenase, and lipoxygenase. Thirdly, EGCG can enhance the activity of enzymes with anti-cancer properties, such as catalase and glutathione S-transferase. Fourthly, EGCG can counteract the proliferation of tumor cells. In summary, EGCG helps restore the normal order of cells, disrupts tumor cells, and accelerates apoptosis (cell death) in cancer cells.
Furthermore, regular consumption of oolong tea can help boost the body's immune system, which also plays a role in cancer prevention and treatment.
To buy oolong tea with better efficacy, it is advisable not to purchase bagged tea or tea with added sugar and flavorings, and instead opt for loose-leaf tea. Loose-leaf oolong tea is typically crafted using various techniques to impart rich flavor and aroma without any additives, with the tea leaves remaining intact. The best loose leaf tea is of high quality in terms of both craftsmanship and raw materials.
Recommended Brewing Method for Oolong Tea
To get the maximum benefits from oolong tea, it's best to consume the tea within two hours after brewing. If you wish to have more, you can simply brew a fresh batch.
The reason for this is that tea contains many antioxidants, which are made up of various unstable hydroxyl groups. Therefore, within two hours of steeping, it is advisable to finish the tea, as these beneficial compounds can undergo changes, potentially losing their cancer-fighting properties and even possibly producing substances that may not be beneficial to the body.
In fact, different types of oolong tea have their own specific brewing methods. I recommend trying iTeaworld's Oolong Tea Sampler, as they not only offer a variety of classic oolong teas but also provide detailed information about these oolong teas, including their origin, tea leaf quality, and brewing methods. This will help you gain a better understanding of oolong tea and select the one that suits your preferences.
It's important to note that the formation of cancer is usually complex, and proactive treatment and adherence to medical advice are of utmost importance. However, maintaining a healthy lifestyle, including regular consumption of oolong tea, can play a supportive role in cancer prevention and treatment. Hopefully, this article has helped you understand some of the knowledge about oolong tea's role in preventing and treating cancer, as well as how to enjoy oolong tea more effectively.