Interviews with Faculty Researchers

– Interview with Prof. Gan Renyou
Assistant Professor, Department of Food Science and Nutrition

Tea, made from the Camellia sinensis plant, is one of the most widely consumed beverages in China and globally. Beyond its cultural significance, tea is rich in bioactive compounds such as polyphenols, polysaccharides, caffeine, and especially epigallocatechin gallate (EGCG), a potent antioxidant linked to numerous health benefits.

Prof. Gan Renyou’s research focuses on how these compounds interact with the gut microbiota, which plays a vital role in breaking down tea components and enhancing their bioavailability and bioactivities. EGCG, for instance, is poorly absorbed in its original form, but colonic bacteria can convert it into more absorbable metabolites, amplifying its in vivo effects, supporting cardiovascular health and potentially preventing cancer.

Another key focus of Prof. Gan’s research is tea fermentation. The six main types of tea—green, yellow, white, oolong, black, and dark—undergo varying degrees of fermentation, each producing distinct chemical profiles. For instance, the unfermented green tea retains higher levels of catechins like EGCG, while the post-fermented dark tea yields theabrownins with unique ingredients that can fight against non-alcoholic fatty liver disease and obesity.

While regular tea consumption is linked to benefits such as improved cardiovascular health, better blood sugar regulation and cognitive support, Prof. Gan cautions against excessive use of concentrated green tea extracts, which may lead to adverse effects like liver damage. His work aims to identify safe and effective dosages, especially for use in supplements.

Tea’s expanding role in functional foods, beverages and even cosmetics, highlights its commercial and therapeutic values. Prof. Gan’s previous experience with patents further supports the development of tea-based bioactives for the health and wellness industries.

Although his findings are largely based on in vitro and animal studies, they lay a strong foundation for future clinical research. In China, where tea is both a daily ritual and a traditional remedy, his work bridges ancient practices with modern science - promoting tea as a powerful tool for preventive healthcare. Finally, tea can be considered as a typical example of “Food as Medicine”.

茶與腸道：透過生物活性成份解鎖健康之門

– 甘人友教授專訪
食品科學及營養學系助理教授

由茶樹種植而成的茶，是中國乃至全球最受歡迎的飲品之一。除了其深厚的文化意義外，茶還富含生物活性成份，例如多酚、多醣、咖啡因，尤其是表沒食子兒茶素沒食子酸酯（EGCG），它是一種強效抗氧化劑，能為人體帶來健康。

甘人友教授主要研究這些成份如何與腸道微生物群互動，當中的腸道菌群在分解茶的活性成份、提升其生物可利用性和生物活性方面發揮著重要作用。例如，EGCG在原始形態下的吸收率極低，但大腸中的細菌能將其轉化為更容易吸收的代謝物，讓其在人體內發揮功效，有助帶來心血管健康，甚至能預防癌症。

甘教授的另一個研究重點是茶葉的發酵過程如何帶來裨益。六大茶類中的黃茶、白茶、烏龍茶、紅茶和黑茶，都需要經過不同程度的氧化與發酵過程，每種都會產生獨特的化學成份。例如，未氧化發酵的綠茶保留了較高水準的兒茶素如EGCG，而後發酵的黑茶則產生出茶褐素，這種物質具有獨特成份，可對抗非酒精性脂肪肝和肥胖等疾病。

雖然日常飲茶能令身體健康，例如改善心血管健康、幫助調節血糖和提升認知功能等，甘教授提醒大眾應避免過量攝取濃縮綠茶萃取物，因其或會帶來肝臟損害等副作用。他的研究目的是確保保健食品所使用的劑量安全有效。

另外，茶在功能性食品、飲品甚至化妝品方面的應用越來越廣泛，顯示出其商業及藥用價值所在。而甘教授在專利方面的經驗，將有助將茶葉活性成份引入到健康產業之中。

雖然這些研究大部份都基於體外與動物實驗，但其已為將來進行臨床研究奠定了基礎。在中國，飲茶既是日常習慣亦是傳統療法，甘教授把古老智慧與現代科學結合起來，推動茶成為預防醫學的重要工具，最終令茶成為「以食為藥」的經典例子。