• Journal of Nutrition and Health
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• 제29권7호
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• pp.713-720
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• 1996

To study the effect of caffeine intake levels on iron metabolism, the iron utilization, iron contents of serum, liver, spleen, kidney, hemoglobin and hematocrit were compared in rats of different sex fed various levels of caffeine (3.5 and 7.0mg/100g body weight) for three weeks. There were no significant caffeine induced differences in feed intake, body weight gain but feed intake of male rats were significantly lower than that of female rats. Hemoglobin, hematocrit and iron contents of the serum were not significantly different between caffeine free and caffeine groups or male and female rats. Iron contents of kidney were decreased by elevation of injected caffeine levels rather than those of liver and spleen. caffeine male groups showed more increased uine volume, urinary and fecal excretions of iron than caffeine free or caffeine female groups. Apparent digestibility and retention of iron were significantly decreased by increment of injected caffeine levels. Male rate rats were more susceptible to injected caffeine on iron excretion than female rats. Current findings suggest that excessive caffeine consumption can affect iron excretion via urine and feces thereby decrease the utilization of iron, and have more significant effect on male than female rats.

• Journal of Nutrition and Health
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• 제25권7호
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• pp.597-607
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• 1992

The present study examined effects of caffeine on coronary circulation myocardial oxygen me-tabolism and calcium release in isolated perfused guinea pig hearts. Intracoronary caffeine({{{{ {10 }^{-5 } }}}}∼{{{{ { 10}^{-3 } }}}}M) was employed for 10 minutes to measure coronary perfusate flow(CF) and coronary vascular sresistance(CVR) at a constant coronary perfusion pressure of 80 cmH2O Perfusate myocardial oxygen consumption(MVO2) and percent oxygen extraction(%EC2) were calcula-ted. In addition calcium contents in both perfusate samples were measured to calculate calcium release in coronary venous effluent. Caffeine significantly decreased CF and increased CVR during 10 minutes of caffeine perfusion regardless of dose of caffeine perfused exhibiting time-response. While % EO2 was significantly enhanced with caffeine MVO2 was markedly reduced. The coronary venous perfusate pH dcreased during the perfusion with caffeine. These changes were consistent with caffeine-induced metabolic acidosis. Calcium release appeared to be dose-dependent and high dose of caffeine greatly increased venous calcium release even 2 minutes after perfusion with carffeine. These finding in dicate that caffeine produced coronary vasoconst-riction with increased calcium release in isolated perfused guinea pig hearts. Additionaly this vasoconstrictor response mignt be due tin part to the direct actions of caffeine.

• Journal of Nutrition and Health
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• 제30권8호
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• pp.911-919
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• 1997

The purpose of this research was to investigate the effect of caffeine levels on calcium utilization in rats of different age and sex. Calcium utilization was compared in rats of different age(4 weeks and 10 months) and sex that were fed various levels of caffeine (0, 3.5, and 7mg/100g body weight) for 3 weeks. There was no significant difference in feed intake, serum calcium level, and ash content in tibia among the groups. Fecal calcium excretion was lower in young rats than in adults, Urinary calcium excretion significantly higher in the caffeine groups than that in the no-caffeine group. Daily retention and apparent absorbability of calcium in young rats were higher than those in adult rats. However, there was no significant difference among groups of different sex and caffeine levels. The results of this study suggest that caffeine consumption promotes urinary calcium excretion.

• 한국환경과학회지
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• 제27권12호
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• pp.1205-1214
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• 2018

During the past few decades, significant increase in the consumption of coffee has led to rapid increase in the production of coffee waste in South Korea. Spent coffee waste is often treated as a general waste and is directly disposed without the necessary treatment. Spent Coffee Grounds (SCGs) can release several organic contaminants, including caffeine. In this study, leaching tests were conducted for SCGs and oxidative degradation of caffeine were also conducted. The tested SCGs contained approximately 4.4 mg caffeine per gram of coffee waste. Results from the leaching tests show that approximately 90% of the caffeine can be extracted at each step during sequential extraction. Advanced oxidation methods for the degradation of caffeine, such as $UV/H_2O_2$, photo-Fenton reaction, and $UV/O_3$, were tested. UV radiation has a limited effect on the degradation of caffeine. In particular, UV-A and UV-B radiations present in sunlight cause marginal degradation, thereby indicating that natural degradation of caffeine is minimal. However, $O_3$ can cause rapid degradation of caffeine, and the values of pseudo-first order rate constants were found to be ranging from $0.817min^{-1}$ to $1.506min^{-1}$ when the ozone generation rate was $37.1g/m^3$. Additionally, the degradation rate of caffeine is dependent on the wavelength of irradiation.

• Investigative Magnetic Resonance Imaging
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• 제21권2호
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• pp.102-105
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• 2017

In adolescents, sleep deprivation problem is getting worse, and increased caffeine consumption is considered to relieve the stress caused by sleep deprivation and academic burden. In this study, immediate neurologic effects of caffeine intake on adolescents were evaluated in three high school students using the ${\gamma}-aminobutyric$ acid (GABA)/creatine ratio on magnetic resonance spectroscopy (MRS). MEGA-PRESS MRS and TE 135 ms single voxel MRS were performed in the anterior cingulate cortex before and after drinking a cup of coffee, which contained 104 mg of caffeine. GABA and creatine were measured on LCModel 6.3, respectively. In all three students, GABA/creatine ratios were decreased after caffeine intake. The GABA/creatine ratios obtained before caffeine intake were decreased after caffeine intake in all the three adolescents. In this preliminary study, caffeine intake caused an immediate decrease in the GABA/creatine ratio in the brain and it may be related to the neurologic effects of caffeine on an adolescent's brain.

• Biomolecules & Therapeutics
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• 제26권5호
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• pp.432-438
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• 2018

Worldwide, caffeine is among the most commonly used stimulatory substances. Unfortunately, significant caffeine consumption is associated with several adverse effects, ranging from sleep disturbances (including insomnia) to cardiovascular problems. This study investigates whether treatment with the Evodia rutaecarpa aqueous extract (ERAE) from berries and its major molecular component, evodiamine, can reduce the adverse caffeine-induced sleep-related and excitation effects. We combined measurements from the pentobarbital-induced sleep test, the open field test, and the locomotor activity test in mice that had been dosed with caffeine. We found that ERAE and evodiamine administration reduced the degree of caffeine-induced sleep disruption during the sleep test. Additionally, we found that evodiamine significantly inhibits caffeine-induced excitation during the open field test, as well as decreasing hyperlocomotion in the locomotor activity test. Additional in vitro experiments showed that caffeine administration decreased the expression of ${\gamma}$-aminobutyric acid $(GABA)_A$ receptor subunits in the mouse hypothalamus. However, evodiamine treatment significantly reversed this expression reduction. Taken together, our results demonstrate that ERAE and its major compound, evodiamine, provide an excellent candidate for the treatment or prevention of caffeine-induced sleep disturbances and excitatory states, and that the mechanism of these beneficial effects acts, at least in part, through the $GABA_A$-ergic system.

• Child Health Nursing Research
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• 제25권1호
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• pp.48-55
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• 2019

Purpose: This study aimed to investigate the status of caffeine-containing energy drink consumption among Korean nursing students and to identify associated psychological factors. Methods: In total, 187 Korean nursing students participated in this cross-sectional study. A self-administered questionnaire was used to identify participants' general characteristics and psychosocial factors (self-esteem, academic stress, depression, and college adjustment) associated with energy drink consumption. Data were analyzed with SPSS using descriptive statistics, the $x^2$ test, the t-test, and logistic regression. Results: More than two-thirds (73.3%) of the participants had consumed energy drinks. Among the investigated psychological factors, depression appeared to most strongly influence energy drink consumption behaviors in this population. Conclusion: The consumption of caffeine-containing energy drinks was found to be common among nursing students preparing to become health care professionals; depressed nursing students were more likely to have consumed energy drinks than non-depressed students. Nursing educators should emphasize the early detection of unhealthy beverage consumption habits and provide appropriate education to enhance healthy behaviors in future health care professionals.

• 한국식품영양과학회지
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• 제46권9호
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• pp.1128-1136
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• 2017

경기도 용인지역에 위치한 고등학교에 재학 중인 고등학생 310명을 대상으로 카페인 함유 식품의 소비 패턴 및 소비 수준에 대한 조사를 실시한 후 결과를 요약하면 다음과 같다. 연구 대상자의 성별은 남학생이 171명(55.2%), 여학생이 139명(44.8%)이었으며 학년은 1학년이 31.9%, 2학년이 34.2%, 3학년이 33.9%였다. 하루 평균 카페인 소비량은 남학생의 경우 41.27 mg, 여학생은 36.47 mg으로 남학생이 많은 것으로 나타난 반면, 몸무게 1 kg당 하루 평균 카페인 소비량은 여학생 0.696 mg, 남학생 0.651 mg으로 여학생이 높게 나타났으나 유의적인 차이는 없었다. 카페인의 소비패턴은 '커피류(남학생 18.95 mg/d, 여학생 26.28 mg/d)'가 성별과 관계없이 가장 많았으며 그다음으로는 '탄산음료류(남학생 14.29 mg/d, 여학생 5.85 mg/d)'로 나타났다. 남학생은 '커피류' 중 '캔커피(P<0.01)'와 '탄산음료(P<0.001)'의 소비가 여학생에 비해 많았으며 여학생(0.33 mg/d)은 남학생(0.24 mg/d)보다 '초콜릿류'의 소비가 많은 것으로 나타났다(P<0.05). 카페인의 하루 평균 총소비량에 대한 각 카페인 함유 식품군의 기여도를 조사한 결과에서도 성별과 관계없이 '커피류(남학생 0.492, P<0.001, 여학생 0.944, P<0.001)'가 가장 높은 표준화 계수 값을 나타냈다. 그다음으로는 성별과 관계없이 '탄산음료류', '에너지음료류' 순이었다. KFDA의 청소년 기준 하루 안전한 카페인 소비량(<2.5 mg/kg)을 기준으로 고등학생들의 카페인 소비 수준을 조사한 결과, 남학생의 3.5%와 여학생의 5.8%가 과잉으로 카페인을 섭취하는 것으로 나타났다. 카페인 과잉섭취군의 하루 평균 카페인 소비량은 여학생(376.82 mg)이 남학생(341.35 mg)에 비해 많았으나 유의적인 차이는 없는 것으로 나타났으며 몸무게 1 kg당 카페인 소비량은 남학생 5.38 mg, 여학생 6.96 mg으로 나타났다. 고등학생의 약 95% 정도가 하루 평균 카페인 소비량이 정상적인 수준을 나타내고는 있으나 일부 고등학생들의 카페인 섭취가 과잉된 것으로 나타났으므로 안전한 카페인의 섭취가 유도될 수 있도록 고카페인 식품에 대한 국가적인 차원의 철저한 관리지침을 통해 안전한 섭취의 유도 및 적극적인 영양교육이 요구된다.

• 한국학교보건학회지
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• 제29권3호
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• pp.132-139
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• 2016

Purpose: In this study, we analyzed the correlation between high-caffeine energy drink intake and mental health in high school students. Methods: Analyses were conducted using the data of 27,097 responses from the 2015 Korea Youth Risk Behavior Web-based Survey of general high school students. Data were analyzed by logistic regression based on a complex sample design. Results: High-caffeine energy drink intake was positively correlated with the rates of smoking, alcohol consumption, violence, depression, and suicidal thoughts and negatively correlated with the sense of happiness. Conclusion: High-caffeine energy drink intake has a significant impact on the mental health of high school students. Therefore, in-depth research and policies on high-caffeine energy drink intake and the mental health of young individuals are required.

• Integrative Medicine Research
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• 제3권1호
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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.