• Journal of Korean Home Economics Education Association
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• v.26 no.4
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• pp.21-34
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• 2014

This study examined the levels of recognition, knowledge, and intake behavior of foods containing caffeine and analyzed the factors affecting amount of caffeine intake to get basic materials for development of educational program for proper intake behavior of foods containing caffeine of high school students in Gyeongbuk region. Of 300 questionnaires that were distributed on December 27, 2013 to February 14, 2014, 255 responses were used for analysis. Frequency distributions, Cronbach's ${\alpha}$, t tests, one-way ANOVA, Pearson's correlation analysis, and regression analysis were conducted by SPSS Windows V.21.0. The mean of the level of concern about foods containing caffeine was 2.76/5.00 points; male and second and third grade students showed lower concern level than female and first grade students. The respondents answered that intake of foods containing caffeine had somewhat harmful effect on health, but it did not much help to refresh and increase concentration. The mean for the percentage of correct answers about knowledge of caffeine was 54.3. Small number of the respondents were advised to reduce intake of caffeine from school teachers or parents. The average of caffeine intake amount was 71.67mg/day; the average for male was 78.98mg/day, whereas for female 61.23mg/day. Almost thirteen percentage of the respondents took caffeine over RDA(Recommended Daily Allowance). According to the result of regression analysis for amount of caffeine intake, grade, BMI, concern about health, perception of whether foods containing caffeine help with refreshment and increase of concentration or not, and experiences of having advice from school teachers to decrease caffeine intake were significant. These results imply that it is necessary for high school students to educate how to take caffeine properly.

• Journal of Nutrition and Health
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• v.52 no.2
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• pp.227-241
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• 2019

Purpose: This study examined the relationship between caffeine intake and metabolic syndrome in Korean adults using the 2013 ~ 2016 Korea National Health and Nutrition Examination Survey data (KNHANES). Methods: The caffeine database (DB) developed by Food and Drug Safety Assessment Agency in 2014 was used to estimate the caffeine consumption. The food and beverage consumption of the 24 hr recall data of 2013 ~ 2016 KNHANES were matched to items in the caffeine DB and the daily caffeine intakes of the individuals were calculated. The sample was limited to non-pregnant healthy adults aged 19 years and older, who were not taking any medication for disease treatment. Results: The average daily caffeine intake was 41.97 mg, and the daily intake of caffeine of 97% of the participants was from coffee, teas, soft drinks, and other beverages. Multivariate analysis showed that the caffeine intake did not affect metabolic syndrome, hypertension, low HDL-cholesterol, and abdominal obesity. Diabetes and hypertriglyceridemia, however, were 0.76 (95% CI: 0.63 ~ 0.93), and 0.87 (95% CI: 0.77 ~ 0.98) in third quintile (Q3), and 0.66 (95% CI: 0.53 ~ 0.82) and 0.83 (95% CI: 0.73 ~ 0.94) in fourth quintile (Q4) compared to Q1, respectively. Therefore, caffeine intake of 3.66 ~ 45.81 mg per day is related to a lower risk of diabetes and hypertriglyceridemia. Conclusion: The study showed that adequate caffeine intake (approximately 45 mg) was associated with a lower prevalence of diabetes and hypertriglyceridemia. Therefore, it can be used as a guideline for the adequate level of caffeine intake for maintaining health.

• Journal of Life Science
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• v.12 no.4
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• pp.375-382
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• 2002

The purpose of this experiment was to examine influence of acute exercise on nocturnal sleep which had been disrupted by caffeine(400mg$\times$3) thought the daytime. Six healthy young males aged 21.0$\times$0.2 yr with a history of low caffeine use. Subjects completed three conditions in a within-subject. At three conditions Sleep EEG were investigated: (1) nocturnal following quiet rest, (2) nocturnal sleep following the consumption of 1200mg of caffeine (3) nocturnal sleep following cycling at 60 min of 60% V $O_{2peak}$ with 1200mg of caffeine consumption. Sleep data were calculated for REM sleep, REM latency, sleep onset latency, sleep efficiency, sleep stages, SWS. Those data were analyzed using repeated-measures ANOVA of change scores. A main effect to, drug(caffeine) indicated that caffeine elicited sleep disturbance that is, TST and sleep onset latency increase and sleep efficiency and stage 4 decrease. The effects of exercise on sleep following caffeine intake generally improve sleep that is, stage 2, 3 and SWS increase and sleep onset latency decrease. A condition effect for sleep indicated sleep improvement after exercise Therefore The data supported a restorative theory of slow-wave sleep and suggest that acute exercise may be useful in promoting sleep and reducing sleep disturbance elevated by a high dose of caffeine.

• Journal of Life Science
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• v.14 no.5
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• pp.741-746
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• 2004

This study investigated the response of GLUT-4 and GRP-78 protein expression in soleus muscle of Streptozotocin-induced diabetic rats with caffeine oral administration by imposing different exercise intensities. Rats were randomly divided into 5 groups (n=6 in each group): diabetic group (D), diabetic-caffeine group (DC), diabetic-caffeine group with low intensity exercise (DCL), diabetic-caffeine group with moderate intensity exercise (DCM) and diabetic-caffeine group with high intensity exercise (DCH). The rats in DCL, DCM and DCH groups were exercised acutely by treadmill running for 8 meter/m, 16 meter/m and 25 meter/m, respectively. Little difference in GLUT-4 protein expression was shown in DC and DCL compared to D. GLUT-4 protein expression was decreased in DCM and increased in DCH was observed. GRP-78 protein expressions in DCL, DCM and DCH were little lower than that of D. An increase in GRP-78 protein was observed in DC. Improved insulin sensitivity with acute high intensity exercise gives the rats important therapy that lowers insulin requirement. This improvement of insulin sensitivity for glucose transport in skeletal muscle results from translocation of the GLUT-4 protein from the endoplasmic reticilum to the cell surface and increase in total quantity of GLUT-4 protein. It is not clear what mechanism reduced GRP-78 protein level in exercise group. It is merely conjectured that caffeine-induced lipolysis provided cells with energy in abundance and this relieved stress which cells are subjected to receive when performing exercise.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.9
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• pp.1128-1136
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• 2017

Previous studies of the caffeine consumption pattern were limited primarily to beverages containing caffeine. Therefore, this study examined the caffeine consumption patterns and levels in beverages and foods containing caffeine among high school students (n=310) in the Yongin region. The participants included 171 boys (55.2%) and 139 girls (44.8%). The daily mean caffeine intake of the respondents was 41.27 mg (0.651 mg/kg) and 36.47 mg (0.696 mg/kg) in boys and girls, respectively. Among the caffeinated food groups, coffee had the highest caffeine intake group in both boys (18.95 mg) and girls (26.28 mg). Girls consumed large amounts of caffeine in the form of Americano-style coffee (20.04 mg), whereas boys consumed more canned coffee (6.77 mg) than girls (2.43 mg, P<0.01). Carbonated soft drinks were the second most prevalent source of caffeine intake in both groups, even though boys (14.29 mg) consumed larger amounts of caffeine than girls (5.85 mg, P<0.001). Multiple regression analysis investigating the major contributing food group to daily total caffeine intake also showed that the highest standardized coefficient was in coffee regardless of gender (boys 0.492, P<0.001 and girls 0.944, P<0.001), followed by carbonated soft drinks and energy drinks. Approximately 95% of high school students consumed normal levels of caffeine, whereas 3.5% of boys and 5.8% of girls consumed excessive amounts based on the standard limit of Korea Food and Drug Administration (<2.5 mg/kg/d) for adolescents. The daily mean caffeine intake of the excess group was 5.38 mg/kg and 6.96 mg/kg in boys and girls, respectively. Consequently, safe daily caffeine intake needs to be determined throughout continuous national management guidelines and nutritional education.

• Journal of Nutrition and Health
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• v.49 no.5
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• pp.367-377
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• 2016

Purpose: This study analyzed the degree of job stress and caffeine intake in workers in industrial positions in order to determine the relationships between job stress and caffeine intake. Methods: For this purpose, this study conducted a survey targeting 361 blue collar workers working for K manufacturing company, Gwangju. Results: The total score for job stress in subjects was $72.7{\pm}6.8points$/100points. According to job stress, subjects were categorized as follows: Q1 for the group who had the least stress; Q2 for the group who had little stress; Q3 for the group who had a lot of stress, and Q4 for the group who had the most stress. As for the effects of caffeine on health, 57.1% thought that caffeine is helpful and not harmful if taken properly while 17.3% responded that less caffeine consumption is better. Daily intake of caffeine according to stress was presented as: $172.0{\pm}85.3mg$ in Q1, $179.0{\pm}83.7mg$ in Q2, $187.9{\pm}81.4mg$ in Q3, and $214.2{\pm}147.3mg$ in Q4 (p < 0.05). The percentages of caffeine consumption compared to the daily safe limit in subjects were: $43.0{\pm}21.3$, $44.8{\pm}20.9$, $47.1{\pm}20.4$, and $53.6{\pm}36.8%$ in Q1, Q2, Q3, and Q4, respectively (p < 0.05). Adverse effects such as nausea or vomiting from caffeine were most common in Q4 (p < 0.05). Conclusion: As a result, higher stress in blue collar workers working for K manufacturing company was associated with more caffeine consumption. Groups with a lot of stress (Q4) consumed approximately 50% of daily safe limit of caffeine. Considering the results above, this study suggests that further research on more precise caffeine intake and its effects is needed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.6
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• pp.709-720
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• 2009

This study was conducted to identify daily caffeine intakes in beverages for elementary school children and to evaluate its effectiveness after nutrition education. The caffeine contents of 140 commercial beverages were analysed by high performance liquid chromatography-ultraviolet detector (HPLC-UV) and information about their consumption were obtained by surveying 267 children. Researchers gave nutrition education to the children, who were 6 to 11 years old and attended 9 classes of 3 elementary schools, by lecture, Powerpoint file and moving picture. Their preference and intake amount on beverages were investigated by questionnaire before and after nutrition education. The order on caffeine contents was coffee ($33.8{\pm}2.4{\sim}49.1{\pm}5.6\;mg/100\;mL$)> coffee milk ($10.6{\pm}3.3\;mg/100\;mL$)> cola ($6.0{\pm}2.4\;mg/100\;mL$)> green black oolong tea drink ($6.0{\pm}2.4\;mg/100\;mL$)> chocolate milk and chocolate drink ($1.6{\pm}0.7{\sim}1.7\;mg/100\;mL$)> black ice tea mix ($1.3{\pm}1.7\;mg/100\;mL$). The order on children's preference was carbonated drink and fruit and vegetable drink (27%)> sports drink (26%)> processed cocoa mix (7%)> milk (6%)> vitamin & functional drink (3%)> green tea drink (2%)> black tea drink and coffee (1%). The average daily caffeine intakes except tea drink was $5.9{\pm}11.2$ mg/person/day ($0.17{\pm}0.32$ mg/kg bw/day), ranged from $0.0{\sim}80.5$ mg/person/day for children. The sources of caffeine were coffee 57% (3.4 mg/person/day), coffee milk 20% (1.2 mg/person/day), carbonated drink 15% (0.9 mg/person/day), chocolate milk and chocolate drink 6% (0.4 mg/person/day), and vitamin & functional drink 2% (0.1 mg/person/day). After nutrition education, the preference of carbonated drink, coffee, vitamin drinks & functional drink was decreased significantly (p<0.05, p<0.05, p<0.01) and the intakes of carbonated drink, chocolate milk & chocolate drink, and vitamin & functional drink were also decreased significantly (p<0.01, p<0.05, p<0.01). This study has shown that nutrition education influences the preference and the intake behavior of caffeinated beverages.

• Journal of Food Hygiene and Safety
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• v.29 no.2
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• pp.105-116
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• 2014

Surveys on the consumption of caffeinated beverages by high school students (n=886) were performed. Of the students, 97.0% consumed a variety of caffeinated beverages, including carbonated drinks (90.0%), processed milk and cocoa (79.0%), coffee (63.0), teas (52.1), energy drinks (16.4%) and nourishment drinks (15.5%). The frequency of intake per student was 8.2 times per week. Caffeine intake through the caffeinated beverages was 41.53 mg/day, which was accounted for by coffee (51.5%), carbonated drinks (19.6%), processed milk and cocoa (11.5%), teas (11.4%), energy drinks (5.0%) and nourishment drinks (1.1%). Students with high levels of stress, those who consumed snacks twice a day, and those who used a computer (or smart phone) for more than 3 hours per day showed significantly higher caffeine intake. The groups with high caffeine intake experienced heart palpitations, insomnia and pollakiuria. Students indicated that they consumed the caffeinated beverages for the taste (57.9%), waking up (18.0%), thirst (13.2%), etc. (10.9%). They tended to consume drinks with a high content of caffeine to sleep less. In addition, they rarely checked the label, and showed a lack of awareness of the caffeine contents in the beverages, which calls for education.

• Journal of Ginseng Research
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• v.30 no.1
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• pp.15-21
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• 2006

This study was carried out to determine the antioxidative activities of tissue cells of mouse kidney isolated from mice fed with different formulation of drinks. The swimming ability of experimental groups without caffeine showed the same pattern, but caffeine group decreased slightly. Superoxide dismutase(SOD) and catalase(CAT) activities of caffeine-containing groups were decreased significantly, but the control and ginseng-containing groups were increased. Hydroperoxide contents did not increase significantly all experimental groups. Hydroperoxlde contents of the control and ginseng-containing groups were similar, but caffeine-containing groups increased. Compared to the control and ginseng-containing groups, lipid peroxidation level and protein contents in caffeine-containing groups were decreased significantly. In conclusion, the antioxidative activities of mouse kidney isolated from mice fed with ginseng-containing products was increased slightly.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.658-663
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• 1993

This study was designed to investigate the effect of dietary vitamin E levels on lipid metabolism in caffeine-fed rats. Male Sprague-Dawley rats were fed on diet containing one of three levels of vitamin E(37.5, 750, or 1,500mg/kg diet0 which was with or without 0.3% caffeine. The rats were sacrificed after 5 and 10 weeks of the feed periods. Results obtained from this study were as follows ; Net weight gain, feed intake and FER in the caffeine added groups were significantly decreased as compared to those of only vitamin E fed group. Liver and kidney weights tended to increase in the caffeine added groups, but spleen and heart weights were not affected. Total lipid contents in serum and liver tended to decrease as dietary vitamin E became increasing and caffeine diet adding. Serum total cholesterol content tended to increase in the caffeine added group. But, liver cholesterol content were decreased. And the higher the dietary vitamin E level became, the lower serum and liver cholesterol contents were. Serum and liver triglyceride contents were significantly lower in the caffeine added groups than in the only vitamin E fed groups. The degree of decrease was more evident as dietary vitamin E level became more increasing. Serum aminotransferase activity was not affected in all experimental groups.