• Integrative Medicine Research
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• v.3 no.1
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• pp.4-10
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• 2014

Green tea and coffee consumption have been widely popular worldwide. These beverages contain caffeine to activate the central nervous system by adenosine receptor blockade, and due to the caffeine, addiction or tolerance may occur. In addition to this caffeine effect, green tea and coffee consumption have always been at the center of discussions about human health, disease, and longevity. In particular, green tea catechins are involved in many biological activities such as antioxidation and modulation of various cellular lipid and proteins. Thus, they are beneficial against degenerative diseases, including obesity, cancer, cardiovascular diseases, and various inflammatory diseases. Some reports also suggest that daily consumption of tea catechins may help in controlling type 2 diabetes. However, other studies have reported that chronic consumption of green tea may result in hepatic failure, neuronal damage, and exacerbation of diabetes, suggesting that interindividual variations in the green tea effect are large. This review will focus on the effect of green tea catechins extracted from the Camellia sinensis plant on type 2 diabetes and obesity, and the possible mechanistic explanation for the experimental results mainly from our laboratory. It is hoped that green tea can be consumed in a suitable manner as a supplement to prevent the development of type 2 diabetes and obesity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.856-861
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• 2002

It has been reported in animal and human studies that green tea shows a health protective characteristics. In the present study, we investigated the disease prevalence according to chronic green tea consumption in 92 subjects (mean age: 59.548.9, men: 41, women: 51) living in green tea cultivation village. The consumption of green tea and other life-style characteristics were ascertained by a questionnaire. The subjects were divided into three groups according to the period of green tea consumption (0, < 10 year, and $\geq$ 10 year). For green tea consumption groups, most of the subjects have been drinking green tea in order to protect disease and recognized the effects of green tea as detoxification of alcohol and smoking, protection of cold or release from fatigue. There were no significant differences in drinking and smoking, physical activity, and a cold prevalence among the groups. Green tea consumption was associated with lower levels of prevalence of tooth decay as well as the osteoporosis. The score of dietary habits was higher by increasing green tea consumption period (p<0.05). Consequently, chronic green tea consumption can be considerably effective in health promotion.

• Journal of Nutrition and Health
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• v.35 no.8
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• pp.854-862
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• 2002

In the present study, we investigated the effects of chronic green tea consumption on the serum lipid profiles of 92 subjects (mean age: 59.5 $\pm$ 8.9, men: 41, women:51) living in a green tea cultivation village. The anthropometric and biochemical blood indices were measured, and nutritional intakes were assessed using 24-h recall method. Also, we administered a questionnaire regarding green tea consumption. The subjects were divided into three groups based on the period of green tea consumption (0, < 10 year, and $\geq$ 10 year). There were no significant differences in age, anthropometric indices (Wt, Ht, BMI, Body fat, LBM), and nutritional intakes among the groups. Serum LDL-cholesterol concentration was significantly lower in the $\geq$ 10 year group compared with the other groups (p < 0.05). Also, the LDL/HDL-cholesterol ratio was significantly lower in the $\geq$ 10 year group compared with the other groups (p < 0.05). The frequency of subjects with a normal range of serum LDL-cholesterol concentration (< 200 mg/dl) was significantly higher in the $\geq$ 10 year group compared with the other groups (p < 0.05). These results imply positive effects of chronic green tea consumption on blood lipid profiles, which requires confirmation in further studies.

• Journal of the Korean Society of Food Culture
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• v.19 no.2
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• pp.184-192
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• 2004

This study was conducted to investigate the perception and using behavior for the Green Tea by a survey. The subjects of this study were consisted of 43.1% of males and 56.9% of females in Daegu city and Gyeong-Sang Buk-Do Province. The main results are as follows : About 85.9% of the participants preferred the Green Tea owing to good for health but the others didn't like owing to not delicious. 51.1% of the subjects had one cup of Green Tea per day. The responses to the 13 questions of the Green Tea were measured on 5 point Likert scale. The item 'Green Tea is natural food' received the highest point but 'Green Tea is delicious' received the lowest. About one half of total subjects knew how to make the Green Tea and 40.4% of them learned the recipes from their mother. About 63.7% replied 'Increasing' prospects for the Green Tea consumption. About 53.7% said the plan should be 'made of good quality Green Tea' for the purpose of better improvement and extention of consumption.

• Journal of Life Science
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• v.21 no.2
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• pp.322-327
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• 2011

The effects of green tea consumption and/or exercise for 12weeks on body weight and select biochemical markers in plasma were evaluated in obese adolescents with a fat ratio of greater than 25%. The subjects were randomly divided into a control group (n=9), green tea consumption group (n=9), exercise group (n=9) and green tea consumption with exercise group (n=9). Subjects in both green tea consumption group and green tea consumption with exercise group were given more than five cups of green tea extract in hot water ($90^{\circ}C$) daily, equivalent to 1.5-1.7 g dry green tea, for 12 weeks. Subjects in both the exercise group and green tea consumption with exercise group participated in a training program (HRmax 60-70%, 60 min/day) for 12 weeks. Control subjects were only given water equal to the quantity of green tea being given to the subjects of green tea consumption. No significant changes body weights were seen in any of these treatments, but the waist to hip ratio was reduced with treatments of both green tea and exercise. The control group showed no significant changes in TNF-$\alpha$, IL-6 and leptin levels. Green tea consumption reduced leptin (p<0.05), TNF-$\alpha$, and leptin levels. Exercise lowered TNF-$\alpha$ (p<0.05), IL-6 (p<0.01), and leptin (p<0.05) concentrations. Meanwhile, a combination of green tea consumption and exercise lowered TNF-$\alpha$, IL-6 (p<0.05) and leptin (p<0.05) levels. These results indicate that green tea consumption and exercise both had a positive effect on the reduction of inflammatory cytokines, TNF-$\alpha$, IL-6 and leptin, in obese adolescents, but no synergistic effect on the reduction of these cytokines.

• Journal of the East Asian Society of Dietary Life
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• v.9 no.4
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• pp.501-513
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• 1999

In order to investigate consumption pattern and image of beverage, this study was performed by using questionnaire based on stratified random sampling about 200 students from September 6, 1999 to September 18, 1999. The result was as followings: 1. For the reasons of each beverage consumption, coke, soda pop and sport drinks were for quenching thirst. And coffee and juices were for dessert and milk.yoghurts, dietary beverages, green tea and ginseng tea were for health. 2. For the priority in selecting each beverage, trademark was dominant factor for choosing coke. And the dominant factor of choosing milk.yoghurts and ginseng tea was nutrition and in case of other beverages taste was the first factor. 3. For the place of taking beverages, coffee, coke and sport drinks were mainly consumed in school and milk.yoghurt and juices in home. 4. The college students loved or liked milk.yoghurt and juices, and they liked or enjoyed coke, soda pop, sport drinks and green tea moderately, and enjoyed ginseng tea and black tea moderately or disliked them. 5. For the frequency of each beverage, many of them consumed coffee and milk.yoghurt once or twice a day. and consumed coke. soda pop. sport drinks and juices once or twice a week. And they answered that they did not consume dietary beverages, green tea, ginseng tea and black tea so often. 6. There was significant correlation with frequency of drinking and preference score of beverage. 7. For the consumption of the Korean traditional beverages, more than 50% of the subjects had no experience in taking sangwha tea, omiza tea, and Kugiza tea. Among them, many answered that they would try the Korean traditional beverages, if they had an opportunity, and that their price was moderate. 8. The results from the analysis of the image of those beverages were as followings; \circled1 Coffee, coke, sport drinks and dietary beverages had a modern image and green tea, ginseng tea and black tea had a traditional image. \circled2 Coke, sport drinks and ginseng tea had a manly image and juices, dietary beverages, green tea and black tea had a womanlike image. \circled3 The students recognized coffee, coke, milkㆍyoghurt, sport drinks, juices, dietary beverages and green tea to be daily and catholic. \circled4 Milkㆍyoghurt, juices, dietary beverages, green tea, ginseng tea and black tea were recognized to be good for health and coffee and coke bad for health. \circled5 Coffee, coke, soda pop, sport drinks, juices and green tea were slightly concerned with a change. \circled6 Coke, soda pop and sport drinks had a dynamic image and coffee, juices. green tea, ginseng tea and black tea had a little static image.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.9
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• pp.1279-1285
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• 2010

This study was conducted to investigate the effects of green tea or coffee consumption on the serum lipids profiles. This study analyzed data of 1,343 participants (753 males and 590 females) among the people who underwent medical check-up. The subjects were divided by three groups as pattern of green tea or coffee consumption. Anthropometric measurements, biochemical analysis and nutrient intake using a food frequency questionnaire were performed. There were no significant differences among groups in height, % body fat, waist circumference, and body mass index. There was no significant difference among groups in energy intake. Fat intake was significantly higher in green tea and coffee group than the control group in men subjects. The intakes of dietary Fe, vitamin A, $\beta$-carotene, and folate was the lowest in coffee group (p<0.05). The intakes of dietary fat was the highest in coffee group in male subjects (p<0.05). Serum concentrations of total cholesterol and LDL-cholesterol were green tea< control< coffee group in order by multivariate analysis after adjusting for confounding factors. The serum concentrations of total cholesterol and LDL-cholesterol were significantly lower in green tea group than coffee group by multivariate analysis after adjusting for confounding factors (p<0.05). However, there was no significant difference in the serum concentrations of total cholesterol and LDL-cholesterol between green tea and control group. These results suggest that green tea consumption didn't show positive effects in preventing hyperlipidemia but coffee consumption showed negative effects in hyperlipidemia.

• Journal of Preventive Medicine and Public Health
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• v.43 no.4
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• pp.366-367
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• 2010

Green tea is a popular beverage and its health benefits are well known. However, inconsistent results have been reported in observational studies concerning the association between green tea consumption and the lung cancer risk. In this commentary, several methodological issues underlying the measurement of tea exposure are highlighted. The recommendations should be useful for designing and planning prospective cohort studies to ascertain the protective effect of green tea against lung cancer.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.4
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• pp.285-296
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• 2016

This study was conducted to obtain a better understanding of American green tea consumers for increasing Korean green tea sales in the US market. In doing so, this study investigated green tea choice attributes of US consumers and segmented them based upon their perceptions about important attributes of green tea. A factor-cluster segmentation approach was used for this study. An exploratory factor analysis identified five green tea choice motives: 'Sensory', 'Diet', 'Price', 'Health', and 'Brand'. Based upon these five choice attributes, cluster analyses classified all respondents into four homogeneous subgroups: 'Highly motivated', 'Taste/Price oriented', 'Health oriented', and 'Brand oriented'. Cross-tab tests proved that green tea consumption and purchasing patterns were significantly different among the four clusters. In particular, two cluster groups representing 'Highly motivated' and 'Health oriented' groups were found to offer the most utility for further American green tea market segmentation research. Findings show that American green tea consumers include a wide range of age groups and they usually buy green tea at grocery markets. Managerial implications for all cluster groups based upon their unique characteristics are provided. Korean green tea companies can apply these findings in order to develop more effective and efficient marketing strategies to attract American consumers to buy more Korean green tea.

• Journal of Nutrition and Health
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• v.56 no.1
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• pp.70-85
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• 2023

Purpose: Several studies have been conducted on the relationship between green tea intake and metabolic syndrome. However, compared to the studies carried out internationally, there is inadequate research on the relationship between domestic green tea consumption and metabolic syndrome. Therefore, in this study, the general characteristics of Koreans according to their green tea intake and its association with metabolic syndrome were examined. Methods: A total of 44,611 subjects were included in the study, and analysis was carried out using data from the Korean Genome and Epidemiology Study (KoGES) for Korean adults aged 40 or older. Green tea consumption was estimated using 106 verified food frequency questionnaires (FFQ). Metabolic syndrome was defined using the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) parameters. After adjusting for confounding variables by performing a Cox regression analysis, the association between green tea consumption and metabolic syndrome was confirmed through the hazard ratio (HR) and 95% confidence interval (CI). Results: The average incidence of metabolic syndrome was 18.7% (20.8% in men and 17.8% in women). Compared to those who drank almost no green tea, in subject groups consuming more than one cup of green tea a day, the metabolic syndrome incidence was significantly reduced by 15% (HR, 0.85; 95% CI, 0.74-0.96; p trend = 0.0200) among men and by 19% (HR, 0.81; 95% CI, 0.73-0.90; p trend < 0.0001) among women. In addition, the biomarkers related to metabolic syndrome also tended to decrease overall in these groups. Conclusion: This study concluded that as the intake of green tea increased, the incidence of metabolic syndrome and related indicators decreased. Therefore, green tea intake is believed to have a positive effect on the prevention and management of the metabolic syndrome.