Green Tea

Originating in China, and infused there from possibly the first century BC, tea is the second most consumed drink in the world after water. It is consumed by more than two-thirds of the world's population. Among all the teas consumed in the world green tea, which is loaded with antioxidants, is the most studied for its health benefits. Accumulating evidence from cellular, animal, clinical and epidemiological studies have linked green tea consumption to various health benefits such as cancer prevention, improving chronic inflammation and degenerative diseases like cardiovascular and liver diseases, diabetes, neurodegenerative diseases, ultraviolet B (UVB)-induced skin aging, arthritis and bone fractures. Although some of these health benefits have not been consistently achieved by intervention trials, positive results from some clinical trials have provided direct evidence supporting the protective effect of green tea against, at least, human cancer. i

A new Japanese study, published on January 7, 2025, provides further evidence that green tea may help fight cognitive decline and therefore reduce dementia risk. In this study 8766 seniors who regularly drank green tea (one cup of tea was equivalent to approximately 200 mL) had fewer of the brain lesions that are characteristic of dementia than those who did not drink it. Interestingly this cross-sectional study included coffee consumption and, while it found a significant association between lower cerebral white matter lesions and higher green tea consumption, coffee did not show similar benefits. This is possibly because green tea’s unique composition, such as catechins, might be more effective against white matter lesions than coffee’s compounds, which are mainly chlorogenic acid and caffeine. The researchers said “green tea consumption may contribute to white matter lesion reduction by improving blood pressure. Moreover, green tea contains less caffeine than coffee, which negatively affects blood pressure, thus suggesting that green tea may have a more beneficial impact on white matter lesions.” The study had some limitations including that there was no information on how the green tea was brewed, leading to potential variations in the content of bioactive substances. ii

Two other human clinical studies from last year investigated the use of green tea topically. One study, from August 2024, showed that green tea extract ointment has a small effect on the healing process and pain reduction of episiotomy wounds. iii In another study, from March 2024, the use of 3% green tea extract cream improved the appearance of stretch marks on the skin.

References

Dou QP. Tea in Health and Disease. Nutrients. 2019 Apr 25;11(4):929. doi:

10.3390/nu11040929. PMID: 31027187; PMCID: PMC6520965.

ii Shibata S, Noguchi-Shinohara M, Shima A, Ozaki T, Usui Y, Taki Y, Uchida K,

Honda T, Hata J, Ohara T, Mikami T, Maeda T, Mimura M, Nakashima K, Iga JI,

Takebayashi M, Ninomiya T, Ono K; Japan Prospective Studies Collaboration for

Aging and Dementia (JPSC-AD) study group. Green tea consumption and cerebral

white matter lesions in community-dwelling older adults without dementia. NPJ Sci Food. 2025 Jan 7;9(1):2. doi: 10.1038/s41538-024-00364-w. PMID: 39774601; PMCID: PMC11707279. iii Sayahi M, Jahangirimehr A, Hatami Manesh Z, Mojab F, Nikbina M. The effect of Camellia sinensis ointment on perineal pain and episiotomy wound healing in primiparous women: A triple-blind randomized clinical trial. PLoS One. 2024 Aug 1;19(8):e0305048. doi: 10.1371/journal.pone.0305048. PMID: 39088486; PMCID: PMC11293732. iv Ayuningsih S, Jusuf NK, Putra IB. Efficacy of green tea ( Camellia sinensis Linn) 3% extract cream on improvement of striae distensae. F1000Res. 2024 Mar 21;13:208. doi: 10.12688/f1000research.142199.1. PMID: 38854441; PMCID: PMC11157189.