• Journal of Nutrition and Health
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• v.29 no.9
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• pp.950-957
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• 1996

This study was designed to investigate the effects of caffeine intake on Ca and P metabolism in ovariectomized rats. For this purpose, the ovariectomized female rats weighing 230.8$\pm$3.5g were divided into four groups, eight rats each ; control, low caffeine(LC), medium caffeine(MC)and high caffeine(HC) groups. They were supplied for six weeks with the caffeine of 0mg, 66.8mg, 167mg and 334mg per kilogram of diet, respectively, and the results are summarized as follows. 1) There were no significant differences in feed intake, feed efficiency ratio and body weight change among all of experimental groups. But liver weight(both total weight and weight/body weight) was significantly decreased by caffeine in MC group. 2) The weight of tibia was decreased by caffeine intake in MC and HC groups. But the length, Ca and P content of tibia and femur was not changed in all of caffeine groups. 3) Ca, PTH and calcitonin levels in serum were not affected by caffeine. While, serum P level in HC group was significantly increased as compared with the control. 4) The fecal excretion of Ca and P tended to be higher in the caffeine groups, and as the result, the absorption rate, retention and retention rate of Ca and P tended to be decreased. It was noteworthy that P retention was significantly lowered in HC group as compared with LC group. The results showed that, when caffeine was taken by ovarietomized rats, the weight of tibia was decreased and the retention rate of Ca and P tended to be lowered. Therefore, too much intake of caffeine for women whose bone mineral density of tibia is decreased after postmenopause seems to accelerate the decrease of bone mineral density due to the negative effect on metabolism of Ca and P.

• The Korean Journal of Zoology
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• v.15 no.4
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• pp.163-182
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• 1972

The effects of caffeine on the ATPase activity and Ca uptake of the fragmented sarcoplasmic reticulum isolated from rabbit skeletal muscle were studied. The ATPase activity of the heavy fraction (2,000-8,000xG) was stimulated by caffeine while that of other lighter fractions was not. It is suggested that the enhancement of the ATPase by the caffeine treatment. The Ca uptake of the heavy and middle (10,000-20,000xG) fractions was inhibited by caffeine when measured at the medium Ca concentration higher than 200 nmoles/mg protein, while only that of the heavy fraction was inhibited when measured at the Ca concentration below 200 nmoles/mg protein. Experiments with dicumarol suggested that caffeine inhibits the Ca uptake of the mitochondria as well as that of the sarcoplasmic reticulum and that the inhibition of the Ca uptake by caffeine in the low Ca concentration in the heavy fraction is due to the inhibition of the mitochondrial Ca uptake by caffeine. It appeared highly probable that the potentiation of muscle contraction caused by caffeine is solely due to the inhibition of the Ca uptake by and to the release of the accumulated Ca from the sarcoplasmic reticulum.

• Toxicological Research
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• v.33 no.2
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• pp.157-164
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• 2017

This study was to evaluate the age-dependent effects of caffeine exposure on the long bones and reproductive organs using male rats. A total of 15 immature male rats and 15 young adult male rats were allocated randomly to three groups: a control group and two groups fed caffeine with 120 and 180 mg/kg/day for 4 weeks. Exposure to caffeine at either dose significantly reduced body weight gain; a proportional reduction in muscle and fat mass in immature animals, whereas a selective reduction in fat mass with relatively preserved muscle mass in young adult animals. The long bones of immature rats exposed to caffeine were significantly shorter and lighter than those of control animals along with decreased bone minerals. However, there was no difference in the length or weight of the long bones in young adult rats exposed to caffeine. Exposure to caffeine reduced the size and absolute weight of the testes significantly in immature animals in comparison to control animals, but not in young adult animals exposed to caffeine. In contrast, the adrenal glands were significantly heavier in caffeine-fed young adult rats in comparison to control animals, but not in caffeine-fed immature rats. Our results clearly show that the negative effects of caffeine on the long bones and testes in rats are different according to the age of the rat at the time of exposure, and might therefore be caused by changes to organ sensitivity and metabolic rate at different developmental stages. Although the long bones and testes are more susceptible to caffeine during puberty, caffeine has negative effects on body fat, bone minerals and the adrenal glands when exposure occurs during young adulthood. There is a need, therefore, to educate the public the potential dangers of caffeine consumption during puberty and young adulthood.

• International Journal of Advanced Culture Technology
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• v.11 no.4
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• pp.216-222
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• 2023

The purpose of this study is to examine the effect of caffeine intake on sleep duration of college students. The data collection period was April 6 to June 30, 2023, and 381 samples were used for final analysis. The general characteristics of the subjects were 38.6% daily water intake of less than 1 liter, caffeine beverage intake was 36.5% once to twice a week, 25.2% three to four times, 13.9% five to six times, 14.7% zero times, and 9.7% more than seven times. The most common purpose of caffeine intake was "to wake up" at 54.6%. factors affecting the subjects' sleep were Caffeine drinks besides coffee and grades. Since this study confirmed that non-coffee caffeine drinks affect sleep duration among caffeine drinks available to students, it is necessary to provide education on caffeine intake control and information that the maximum daily intake is 400 mg for college students.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.3
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• pp.363-371
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• 2010

The purpose of this study was to examine the impact of caffeine on lipid concentrations in ovariectomized rats. Forty-four rats (75${\pm}$5 g) were randomly divided into ovariectomy(ovx) and sham groups, each of which were randomly divided into two subgroups that were fed the control diet or a caffeine-supplemented diet (0.03%/diet). The experimental groups were classified into 1) sham-control, 2) sham-caffeine, 3) ovx-control and 4) ovx-caffeine groups. All rats had been fed on experimental diet and deionized water ad libitum for 6 weeks. Triglyceride concentration and total cholesterol were measured in serum and liver. Serum HDL-cholesterol was measured. Serum LDL-cholesterol and atherogenic index were calculated. Weight gain and food efficiency ratio were higher in ovx groups than in sham groups (p<0.05). Caffeine intake did not affect weight gain and food efficiency ratio. Mean food intake was significantly increased in ovx-caffeine group than other three groups. There were no significant differences in serum triglyceride, total cholesterol, HDL-cholesterol, LDL-cholesterol and atherogenic index between the control diet group and caffeine diet group. In addition, hepatic triglyceride and cholesterol level was unaffected by caffeine intake or ovariectomy. Therefore, we suggest that caffeine (0.03%/diet) intake may not have adverse effects on serum lipid level in ovariectomized rats.

• Journal of Pharmaceutical Investigation
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• v.34 no.2
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• pp.131-138
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• 2004

This study was aimed to investigate the feasibility of nasal delivery of caffeine for the elimination of sleepiness. The effects of various vehicles, solubilizers, and enhancers on the permeation of caffeine through rabbit nasal mucosa was observed. The permeation study was carried out using a Franz-type permeation system at $37^{\circ}C$, and the amount of caffeine permeated though the rabbit nasal mucosa was determined by a validated HPLC. The apparent solubility and phys iochemical stability of caffeine in various nasal formulations were was determined. The effect of hydrotropes and modified cyclodextrins on the solubility of caffeine in water was determined by equilibrium solubility method. The solubility of caffeine in water was 29 mg/mL at $30^{\circ}C$. The addition of sodium benzoate and nicotinamide at 10% improved the solubility of caffeine (115 and 132 mg/mL, respectively) in aqueous solution. The flux of caffeine though the nasal mucosa from aqueous solution was $2.1{\pm}0.26\;mg/cm^2/hr$. The addition of sodium benzoate reduced its permeation $(1.4{\pm}0.01\;mg/cm^2/hr)$, but sodium benzoate with 5% $2HP{\beta}CD$ and 0.03% monoterpenes increased its permeation $(2.4{\pm}0.04\;mg/cm^2/hr)$ markedly. The addition of nicotinamide also increased also increased its permeation $(2.5{\pm}0.36\;mg/cm^2/hr)$. markedly. As the concentration of caffeine in nasal formulation increased, the permeation flux increased linearly. Caffeine was stable physicochemically and enzymatically in the nasal mucosa extract at $37^{\circ}C$. These results suggest that caffeine can be efficiently delivered nasally and the development of nasal formulation will be feasible.

• Investigative Magnetic Resonance Imaging
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• v.21 no.2
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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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• v.26 no.5
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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.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.677-687
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• 2017

Caffeine has a long history of human consumption but the consumption of caffeine due to caffeinated energy drinks(CEDs) is rapidly growing. Marketing targets of CED sales are children, adolescents and young adults, possibly caffeine-sensitive groups and its effect for them can be significantly different from healthy adults. Caffeine-related toxicities among these groups are growing in number and a number of countries are recognizing severity of caffeine toxicities. Previous research showed prediction of maximal plasma caffeine concentration profiles after the single CED ingestion and the primary aim of this study is to visually predict plasma caffeine concentration after the single and multiple ingestion of standard servings of CED. Based on the population pharmacokinetic model using Monte Carlo simulation, prediction of caffeine concentration leading to caffeine intoxication in the sensitive groups is quantitatively presented and visualized. This research also broadens the perspective by creating and utilizing diverse open science tools including R package, Edison Science App and Shiny apps.

• Journal of the Korean Society of Food Science and Nutrition
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• v.4 no.1
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• pp.45-48
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• 1975

Coffee is a popular beverage with many people at home and in the tea-room. Caffeine is a major chemical compound of coffee. A little caffeine is a stimulant to the movement and spiritual nerve, but much caffeine influences sleep, nervousness, non-concentration, headache and giddiness depending upon each person. The writer expresses the result of the caffeine content in the coffee which is collected from the coffee- shops of Seoul. The contents are as follows : 1) Caffeine content of the coffee of the tea-room was researched dividing into the central Seoul city and the outskirts of Seoul. 2) Caffeine content of the coffee in the outskirts tea-rooms is $0.32{\sim}1.23mg/ml$ and the average is 0.546mg/ml (SD 0.19). 3) Caffeine content of the coffee of the central city is $0.34{\sim}0.73mg/ml$ and the average is 0.513mg/ml(SD 0.12). 4) There was no difference between the outskirts and the central city. 5) Caffeine content of the coffee of the tea-rooms according to each season is going to be researched.