Interview with Assistant Professor Kazutoshi Chayama from Shizuoka University
We interviewed Professor Chayama, an expert in Japanese green tea nutrition. In his studies, he has found that Japanese green tea limits fat accumulation in the body, preventing obesity. In this conversation we ask him about the scientific mechanism.
Biography Assistant Professor Kazutoshi Chayama from Shizuka University’s Faculty of Agriculture, Symbiosis and Bioscience.
Professor Chayama studies the physiological function of food and natural elements. He has written many theories on the effects of the Japanese green tea. This includes the effects Japanese green tea has in combating cancer. Shizuoka, in central Japan, is also well known as one of the biggest production sites of Japanese green tea in Japan.
DS: Could you please tell us why you started studying Japanese green tea?
Professor Chayama: Initially my studies did not focus on Japanese green tea. I studied Breast Cancer in the Medical Research Laboratory (MRL) at Tokyo University. One day, I read an epidemiology study that showed those living in the Kawane area within Shizuoka Prefecture suffered from cancer less than other areas. Furthermore, in Kawane people frequently drink Japanese green tea. Based on this study, my advisor told me to research Japanese green tea.
DS: I see. You had some previous research on Japanese green tea before jumping in to your own research.
Professor Chayama: Yes, but we faced many challenges to obtain visible results. After I started studying Japanese green tea, I had the opportunity to move to Shizuoka University. I also started to investigate if Japanese green tea had any effect on the AIDS virus. This study did not have significant results however, the experiment triggered continuous studies of the effects of Japanese green tea. When we dissected the mice we used in the cancer experiments, we realised the mice that drank green tea had less belly fat.
Professor Chayama: Our data showed that the mice that drank Japanese green tea possessed 40% less fat. Based on this data, we experimented with varying amounts of crushed Japanese green tea leaves in their feed for a prolonged time period. We found that adding more than 2% of crushed Japanese green tea leaves dramatically reduced the amount of fat in mice. We also found that the fat in their blood decreased. With these results, we worked with Japanese companies to introduce the Japanese green tea into foods and drinks that are certified by Food for Specified Health Uses (authorised by the Japanese Government).
Professor Chayama: The key elements in Japanese green tea are Catechins, Theanine, and Caffeine. Tea also has Vitamin C and other elements, but for our research we focus primarily on Catechins and Theanine, which are unique to Japanese green tea.
DS: How about those concerned about their caffeine consumption?
Professor Chayama: Of course too much caffeine is bad for health however, Caffeine plays an important role in Japanese green tea. A suitable amount of Caffeine creates a deep taste in brewed tea. Caffeine also has health benefits in preventing fat accumulation particularly when people consume Caffeine with Theanine and Catechins.
DS: Could you provide more details on how the three elements work?
Professor Chayama: They work with enzymes made by the liver. Our liver produces two enzymes. One synthesises fat, while the other decomposes fat. Consuming both Catechins and Caffeine can reduce the enzyme synthesising fat and increase the one decomposing fat. The combination of Caffeine and Catechins is unique to Japanese green tea, and is not found in coffee.
Professor Chayama: We also discovered that Japanese green tea reduced the appetites of the mice we experimented on. Japanese green tea activates the hormone called Incretin, which produces the signal “to stop eating”. Thus far we have only tested on mice, but we plan to continue the study with human beings.
For example, we found out that the benefits of mixing a Japanese green tea called Benifuuki with ginger. Ginger has a metabolism boosting effect, thus mixing it with Benifuuki boosting the effect of reducing fat accumulation.
DS: That is very exciting that blending Japanese green tea with other ingredients can not only produce a wide variety of taste, but also increase the health benefits! Thank you for the interview Professor Chayama.
After the Interview
Professor Chayama explained the scientific facts using non-technical languages. The health effects of Japanese green tea that we knew by word of mouth have now been supported by scientific facts. It is now recommended by science that we should get a cup of matcha a day.