• The Korean Journal of Community Living Science
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• v.16 no.1
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• pp.59-64
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• 2005

This study is to find out effects of hot water soluble extract from green tea, one of the Korean favorites, on the calcium metabolism and bone strength in body. To do so, calcium, phosphate, creatinine concentration and ALP activity in blood and the content of calcium and ash in the organ, the length, weight, strength in bone were measured. In addition, to find the calcium metabolism, the level of calcium intake, excretion, retention were measured. Twenty male Sprague-Dawley rats were divided into two groups and isoloated soy protein was provided as the source of protein and CaCO₃ was provided as the source of calcium. 0.5% hot water soluble extract from green tea was provided to the green tea groups and for the control group deionized water was provided. The results are as follows ; 1. There is no difference between the experimental groups in diet intake, weight gain, and the feed intake. 2. Feed efficiency ratio was low in the group which hot water soluble extract from green tea was provided. 3. There is no difference between groups the level of calcium, phosphorus, creatinine and ALP activity in serum. 4. There is no difference between groups weight, contents of ash and calcium in kidney and liver. 5. There is no difference between groups in calcium intake, absorption, excretion, and retention. 6. There is no difference between groups weight, length and strength in bone. In summary, when hot water soluble extract from green tea was provided with the amount of 150-200mg, which is taken when people generally drink as favorite tea, weight gain was reduced due to the decrease of feed efficiency ratio. However, it did not affect the availability of calcium in body at all. Thus, even if a big quantity of green tea powder or solid of hot green tea extract is not provided, the quantity obtained when people drink green tea lowers the feed efficiency ratio without reducing availability of calcium in body.

• Korean Journal of Community Nutrition
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• v.13 no.2
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• pp.189-198
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• 2008

This study investigated the influences of the beverage intake on food behavior and personality for 1295 adolescents. The results were as follows. The favorite beverage was 'fruit juice', and preference of 'coffee' was the lowest. 'Milk and dairy product' was highest and 'milkshake' was lowest in intake frequency of beverage. The preference correlated positively(r = 0.391) with the intake frequency of beverage, especially high in 'green tea and black tea'(r = 0.622), 'coffee'(r = 0.581), 'carbonated drink'(r = 0.538), and 'milk and dairy product'(r = 0.501). The explanation power(R2) of beverage preference on beverage intake was 0.153. The explanation power($R^2$) of beverage intake on food behavior was 0.127, and 'carbonated drink' and 'coffee' as well as 'milkshake' had a negative influence on food behavior: however, 'milk and dairy product', 'green tea and black tea', and 'fruit juice' had a positive influence on food behavior. The relationship of beverage intake and sociality was very low($R^2$= 0.013), and 'isotonic drink' and 'green tea and black tea' had a positive influence on sociality. The relationship between beverage intake and anger expression was also very low. 'Coffee' showed a positive relationship with anger-in. 'Carbonated drink' and 'milkshake' showed a positive result with anger-out. 'Milkshake' showed a negative relation with anger-control, but 'green tea and black tea' and 'milk and dairy product' showed a positive relation. From these results, it was necessary to develop the practical nutritioneducation program on proper beverage choice for adolescents leading to better metal and physical status.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1190-1196
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• 2006

This experiment was carried out to investigate the effects of Korean, Japanese and Chinese green tea on laying performance and egg quality in hens. A total of 168 "Tetran Brown" hens aged 40 weeks were assigned to 7 treatments in a completely randomized design. Each treatment had 4 replicates accommodating 6 layers per replication. The seven dietary treatments were: 1) control diet with no green tea added, 2) diet containing 1.0% Korean green tea (1.0% KGT), 3) diet containing 2.0% Korean green tea (2.0% KGT), 4) diet containing 1.0% Japanese green tea (1.0% JGT), 5) diet containing 2.0% Japanese green tea (2.0% JGT), 6) diet containing 1.0% Chinese green tea (1.0% CGT), and 7) diet containing 2.0% Chinese green tea (2.0% CGT). Egg production rate of the layers fed diets containing 1.0 or 2.0% green tea powders were significantly increased compared to that of the control (p<0.05). The egg weight of layers was significantly reduced in layers fed 1.0% CGT (p<0.05). The feed intake was significantly decreased in KGT and CGT groups at 2.0% inclusion levels (p<0.05). The egg shell thickness and shape index of JGT treatment was significantly lower than that of the control (p<0.05). There were no significant differences in albumen index, yolk index and Haugh unit of eggs for layers fed diets containing green tea powders regardless of origin (p>0.05). Green tea feeding to layers tended to reduce the overall cholesterol content of egg yolk. Particularly, 1.0 or 2.0% CGT significantly depressed the total cholesterol content of egg yolk (p<0.05). In conclusion, incorporation of 1.0 or 2.0% Korean, Japanese and Chinese green tea into layer diets regardless of origin had favorable effects on laying performance and egg quality profiles. Among the three green tea sources, the Chinese green tea powder had the highest reducing effect on cholesterol content in egg yolk.

• Journal of Nutrition and Health
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• v.46 no.4
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• pp.324-331
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• 2013

We investigated dietary effects of green tea powder (GTP) on plasma lipids, platelet aggregation, hemolysis, plasma TBARS, and liver enzymes. Thirty one volunteer diving women living on Jeju island consumed 4 g green tea powder daily for a period of four weeks and data for the study subjects were analyzed on the basis of diagnostic criteria for blood pressure (BP)(${\geq}$ 140/90 mmHg), plasma total cholesterol (TC)(${\geq}$ 200 mg/dL), and triglyceride (TG)(${\geq}$ 150mg/dL). Subjects with high BP had significantly higher TC and TG than those with normal BP. Subjects with higher TC had higher TG, and those with higher TG had lower HDL cholesterol. Platelet aggregation in the initial slope was significantly higher in subjects with normal BP, normal TC, or normal TG than their counterparts in high BP, TC, and TG. HDL cholesterol after GTP intake increased only in subject groups with normal BP, normal TC, or normal TG, and plasma TG after GTP intake decreased only in groups with higher BP, higher TG, or higher TC. Plasma TC and TG in subjects with normal BP increased after GTP intake. GTP intake caused a decrease in the initial slope of platelet aggregation in all subject groups with little effect on maximum aggregation. Total bilirubin showed a significant increase and GOT increased in all subject groups after GTP intake. Beneficial effects of short term intake of green tea powder might differ depending on the subject conditions in terms of blood pressure, plasma lipids, and other cardiovascular conditions. However, with the hypolipidemic, antithrombotic, and antioxidant actions of its bioactive flavonoids, long term usage of GTP or brewed green tea may provide preventive effects against cardiovascular disease.

• Journal of the Korean Society of Food Culture
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• v.22 no.4
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• pp.420-433
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• 2007

This study was performed to investigate the effect of the health related factors on the preference and frequency of intake of coffee and traditional beverages among 280 university students (128 males and 152 females) who were residing in Incheon areas. The results were as follows; 1. Male students of over weight and obese were more than female students and female students of under weight were more than male students. Female students were interested in weight control and had an experience in weight control more than male students. 2. The group who was much interested in weight control preferred green tea, yuja tea and dunggulre tea. The group who was much interested in health when drink beverages preferred green tea, ginseng tea, dunggulre tea, vinegar drinks and water but didn’t prefer coffee. 3. The frequency of intake of green tea is high in the group who had an experience in weight control. And the frequency of intake of honey tea was high in the group who drank alcohol almost every day. Coffee intake was the highest among beverages in smokers and water intake was the highest among beverages in nonsmokers. In conclusion this study showed that as an interest in health is higher, the preference and frequency of intake of coffee was low whereas those who intake of traditional beverages was high in general.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1769-1774
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• 2005

This experiment was carried out to evaluate the effects of feeding green tea powder on laying performance and egg quality in hens. A total 180 'Tetran Brown' laying hens aged 40 weeks were assigned to 6 treatments in a completely randomized design. Each treatment consisted of five replicates accommodating six layers per replication. The experimental diets were a negative control containing no green tea, a positive control diet containing antibiotics (0.05% chlortetracycline) and diets containing 0.5%, 1.0%, 1.5% and 2.0% green tea powder. Egg production rate of layers fed the diets containing green tea powder did not differ significantly from that of the negative and positive controls (p>0.05). Egg weight was decreased significantly in the group fed the diet containing 0.5% green tea powder (p<0.05). Feed intake of layers was significantly higher for the diet containing 1.5% green tea powder compared to that of negative and positive control diets (p<0.05). The eggshell thickness reduced significantly in the layer group fed the diets containing green tea powder regardless of dietary levels (p<0.05). Green tea powder tended to reduce egg yolk cholesterol in this experiment. Particularly, dietary 2% level of green tea powder significantly suppressed the cholesterol contents of the egg yolk (p<0.05). Thiobarbituric acid value (TBA) of egg yolk was significantly reduced by green tea diets (p<0.05). The yellowness of egg yolk was increased in the layers fed the 2.0% green tea diet compared with that of control diet (p<0.005). The Linoleic and $\alpha$-linolenic acids tended to increase in the group fed diets containing 1.5% green tea powder even though there were no significant differences among treatments (p>0.05). The oleic and docosahexaenoic acid contents of the egg yolk were similar among treatments (p>0.05). Based on the results of the experiment, it is concluded that green tea powder inclusion in the diet for layers at 2.0% level can reduce the cholesterol content and TBA value of the egg yolk, implying its potential effect on egg quality parameters.

• Nutritional Sciences
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• v.8 no.3
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• pp.175-180
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• 2005

Green tea, which has high polyphenols amount, is thought to have hypocholesterolemic effects. The present study was performed to further examine the hypocholesterolemic action of green tea, especially (-) epigallocatechin gallate (EGCG) for its effect on diet-induced hypercholesterolemia in rats. Male Sprague-Dawley rats (n=15) were fed a green tea-free diet (control), $1.0\%$ green tea catechin (catechin) or $0.5\%$ green tea catechin EGCG for seven weeks. Hypercholesterolemia was induced by adding $1\%$ cholesterol and $0.5\%$ cholic acid to all diets. There was no difference in food intake and body weight gain among the groups. The green tea EGCG treatment led to a significant improvement in plasma levels of total cholesterol, low density lipoprotein (LDL)-cholesterol and high density lipoprotein (HDL)/LDL ratio (p<0.05). There was no significant effect on the plasma HDL-cholesterol level. The catechin treatment led to a 4.19-fold increase in the LDL-receptor mRNA level compared to the control, but the EGCG treatment did not affect the hepatic LDL-receptor mRNA level. Our results suggest that when blood cholesterol level is down-regulated by green tea EGCG, the LDL receptor gene-independent pathway may dominate the hypocholesterolemic action of EGCG.

• Journal of the Korean Society of Food Culture
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• v.21 no.1
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• pp.8-16
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• 2006

This study was performed by questionnaire to investigate the preference and intake frequency of Korean traditional commercial beverages. The subjects were consisted of 320 participants in Daegu and Kyungpook area. 'Chain market' scored 49.4% as purchasing place of traditional beverages. 'Tea bag' scored 31.6% as the favorite package of traditional beverages. On the reasons of drinking traditional beverage 'good for health' scored the highest with 31.3% respondents, followed by 'good smell' with 14.4%. Coffee and traditional tea were the choice of beverage after having a rich meal and on occasion of entertaining guests. The favorite foods in ordinary days were 'tea', 'alcohol', 'ice cream', 'nuts' and 'cookie'. More than thirty percent of the respondents, both male and female, raised the need of improvement in taste of traditional beverage. In the intake frequency, Korea traditional beverages obtained 1.80 points as a whole. 'Green tea' scored highest(3.40points) while 'mulberry-leaf tea' received the lowest score of 1.31 points. The preferred Korean traditional drinks were 'greed tea', 'shick hae', 'citron tea', 'misitgaru', 'maesil tea', 'rice tea' in the order. On the other hand, the preference for 'mulberry-leaf tea', 'boxthom tea', 'ginger tea', 'chrysanthemum tea' and 'omija tea' was very low. The people who are on twenties preferred 'shick hae', 'honey tea', 'citron tea', 'black tea' and 'misitgaru' more than the other generation.

• 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.