Green tea – a long-standing traditional beverage – attracts attention due to its high antioxidant content. However, does the habit of drinking tea every day really help prevent cancer as many people hope?
The anti-cancer effects of green tea
According to Dr. Le Tieu Nhat, a lecturer in the Faculty of Traditional Medicine, University of Health Sciences , Vietnam National University Ho Chi Minh City, green tea (Camellia sinensis) is a familiar beverage, especially popular in Asian culture. The main active ingredient in green tea is polyphenol, mainly belonging to the catechin group. Among them, EGCG is the dominant catechin and has been studied the most, thanks to its strong antioxidant properties.
Meanwhile, cancer originates from the excessive proliferation of abnormal cells, which are closely linked to damage caused by prolonged oxidative processes.
Animal and in-vitro studies have shown that flavonoids in green tea, particularly EGCG, have anticancer potential through multiple complex mechanisms, not just antioxidant effects. This compound can inhibit the formation of blood vessels that nourish tumors, while catechins also help suppress the growth, invasion, and metastasis of cancer cells, as well as regulate cell proliferation. Several recent meta-analyses have also noted an association between the consumption of green tea or green tea products and a lower risk of cancer.
Drinking green tea can be considered part of a healthy lifestyle.
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There are still limitations in terms of scientific evidence.
Much of the current evidence comes from studies using pure (unprocessed) flavonoids, and therefore does not fully reflect the effects of green tea when consumed in practice. Results from animal studies are also difficult to extrapolate to humans due to differences in metabolism and microbiome.
Meta-analyses show conflicting results, with many studies having small sample sizes. Green tea may only help prevent certain types of cancer, and its effectiveness depends on the type of tea and preparation method. Additionally, green tea drinkers tend to have healthier lifestyles, which can confound the results.
Green tea can also cause side effects such as digestive disorders, insomnia, restlessness, mild hypertension, mild liver toxicity, or skin allergies, especially with the extract form. Drinking tea that is too hot (>65°C) also increases the risk of esophageal cancer.
EGCG in green tea has strong antioxidant properties.
PHOTO: AI
Drinking green tea as part of a healthy lifestyle.
According to Dr. Le Tieu Nhat, although current studies have not provided enough conclusive evidence to confirm that green tea is the absolute "key" to cancer prevention, we cannot deny the biological potential and health benefits that this beverage offers.
Instead of viewing green tea as a cure-all, consumers should approach drinking it as part of a healthy lifestyle. To maximize benefits and minimize side effects, maintain a habit of moderate tea consumption, ensuring the serving temperature is below 65°C, and combine it with a balanced diet and regular health checkups.