ARTICLE | doi:10.20944/preprints202104.0527.v1
Subject: Life Sciences, Biochemistry Keywords: caffeine, pre-pregnancy, pregnancy, intake, quintiles
Online: 20 April 2021 (11:08:10 CEST)
We aimed to assess the caffeine intake before and during pregnancy, compliance with caffeine recommendations during pregnancy (200 mg/day) and factors associated with higher intakes before and in first trimester of pregnancy. Caffeine consumption was collected in a Spanish cohort of pregnant women through a validated food questionnaire, before and in each trimester of gestation (T1, T2 and T3). 463 pregnant women were recruited and follow-up through pregnancy. Compliance with caffeine intake recommendations during pregnancy and quintiles of mg/day of caffeine before and in T1 of pregnancy were calculated. A multivariate logistic regression, comparing extreme quintiles of consumption (Q1 vs Q5) was used. Mean caffeine intake before pregnancy was 120.05 mg/day (SD 117.85), 42.76 mg/day (SD 63.90) at 12th GW, 42.00 mg/day (SD 59.76) at 24th GW and 39.34 mg/day (SD 50.9) at 32nd GW (p<0.001). 86% of women complied with caffeine recommendations during pregnancy. At pregnancy (T1), being an active smoker was associated with Q5 > 100.1 mg/day, aOR = 22.69; 95% CI 4.67- 110.26. igh diet quality, aOR = 0.30; 95% CI, 0.13- 0.68, and moderate physical activity level, aOR= 0.44; 95% CI, 0.19-1.00, were inversely associated with Q5 > 100.1 mg/day. Pregnant women are mostly adhering to current caffeine intake guidelines. Higher caffeine intake at pregnancy is associated with other unhealthy habits during pregnancy.
REVIEW | doi:10.20944/preprints201808.0405.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: caffeine; coffee; systematic review; pregnancy; safety
Online: 23 August 2018 (05:33:43 CEST)
In 2016–2017, we conducted and published a systematic review on caffeine safety  that set out to determine whether conclusions presented in the heavily cited Health Canada assessment, Nawrot et al. , remain supported by more recent data. To that end, we reviewed data from 380 studies published between June 2001 and June 2015, which were identified from an initial batch of over 5,000 articles through a stringent search and evaluation process . In the current paper, we use plain language to summarize our process and findings, with the intent of sharing additional context for broader reach to the general public. We addressed whether caffeine doses previously determined not to be associated with adverse effects by Health Canada (400 mg/day for healthy adults, 300 mg/day for pregnant women, 2. 5 mg/kg body weight/day for adolescents and children, and 10 g/day for acute effects) remain appropriate for five outcome areas (acute toxicity, cardiovascular toxicity, bone & calcium effects, behavior, and development and reproduction) in healthy adults, pregnant women, adolescents, and children. We used a weight-of-evidence approach to draw conclusions for each of the five outcomes, as well as more specific endpoints within those outcomes, which considered study quality, consistency, level of adversity, and magnitude of response. In general, updated evidence confirms the levels of intake put forth by Nawrot et al., as not being associated with any adverse health effects, and our results support a shift in caffeine research from healthy to sensitive populations.
ARTICLE | doi:10.20944/preprints202011.0598.v1
Online: 23 November 2020 (20:15:40 CET)
Objectives: To determine the effects of caffeine consumption on the sleep habits and lifestyle of medical students. Methods: A cross-sectional study was conducted at Jinnah Sindh Medical University (JSMU) and Hamdard College of Medicine. On 422 undergraduate students aged 18-25 years, through random sampling. The duration of the study was from January 2019 to June 2019. The data was collected through self-administered questionnaire which included data regarding sleep habits and lifestyle of medical students. Results: Majority (81.6%) of the students consumed caffeine while only (18.4%) did not. One third of the participants (31.8%) reported caffeine consumption increased their academic performance and (57.3%) reported that it does not. More than half of the participants (63.3%) who consumed caffeine slept during class, whereas (47.2%) never had difficulty in falling asleep during the night. Conclusion: This research concluded that caffeine does have some role on sleep habits of medical students as they tend to have less sleep hours, experience day time dysfunction, average quality of sleep, and falling asleep during class. It has been concluded that caffeine has no effect on eating habits of medical students however, it does increase the screening time, keeping them active.
ARTICLE | doi:10.20944/preprints201801.0105.v1
Subject: Behavioral Sciences, Other Keywords: energy drinks; adolescent lifestyle; alcohol; caffeine; sports
Online: 12 January 2018 (05:12:03 CET)
The European Food Safety Authority (EFSA) has identified some risk factors for the occurrence of side effects linked to energy drinks (EDs) consumption by young people. Tachycardia, sleeplessness, caffeine addiction may be caused by excessive consumption of EDs during parties, sport matches, ect. EDs consumption has been evaluated in a sample of students in Italy together with some aspects of their lifestyle. The survey was performed in two high schools from September 2014 to June 2015. 583 students between 14 to 18 years were recruited and a standard questionnaire (EFSA checklist) was used to collect information on responders characteristics, beverages consumption, EDs with alcohol, and EDs and sports. 350 out of 583 responders (60%) consumed EDs and 146 out of 583 responders (25%) reported an occasional alcohol consumption. Despite 82 out of 146 alcoholic drinkers (56%) were EDs-alcohol consumers, only 70 out of 583 adolescents (12%) reported habitual EDs consumption. Moreover, 38 out of 379 (10%) of all physically active adolescents reported frequent EDs consumption before sportive trainings. Study results highlight the need for primary prevention measures in communication campaigns and training delivered by school to limit potential health threats related to excess of EDs consumption.
ARTICLE | doi:10.20944/preprints202203.0292.v1
Subject: Chemistry, Analytical Chemistry Keywords: paracetamol; ibuprofen; caffeine; classical least-square; simultaneous; spectroscopy
Online: 22 March 2022 (03:26:27 CET)
In this paper, the classical least square (CLS) method with molecular absorption spectrophotometric measurement was used to determine simultaneously of paracetamol (PAR), ibuprofen (IBU), and caffeine (CAF) in tablets. The absorbance spectra of the standard solutions and samples were measured over a wavelength from 220 to 300 nm with a 0.5 nm step. The concentration of PAR, IBU and CAF in the sample solutions were calculated by using a program called CLS-Excel written in Microsoft Excel 2016 and Visual Basic for Applications (VBA). The method and CLS-Excel program were tested on mixed standard laboratory samples with different PAR, IBU, and CAF concentration ratios, and they showed small errors and satisfying repeatability. An analytical procedure for tablets containing PAR, IBU, and CAF was developed. The reliability of the procedure was proved via the recovery and repeatability of the analysis results with an actual tablet sample and comparing the mean contents of active substances in the tablets obtained from the analytical procedure with the from the HPLC method. The procedure is simple with a reduced cost compared with the HPLC standard method.
ARTICLE | doi:10.20944/preprints202005.0254.v1
Online: 15 May 2020 (10:22:59 CEST)
In addition to being a source of freshener, coffee has an enormous possibility to be developed as a source of antioxidants for functional beverages. However, efforts to increase the value added of coffee as a health functional drink are still hindered by the presence of high level of caffeine, which is thought to have adverse effects on health, especially for coffee lovers who are vulnerable to caffeine. This study aims to optimise the steaming duration to produce low caffeine coffee while maintaining the sensory attributes and antioxidant compounds contained in it. Indonesian Arabica (Leksana variety) green coffee beans were steamed with multi-level steaming durations (0, 20, 40, 60 and 80 min) followed by roasting (medium-dark roast degree), grinding, and brewing (espresso method). The results indicate that caffeine content in the coffee was inversely proportional to the steaming duration. The lowest caffeine content was obtained from the treatment of 80 min steaming with a decrease of caffeine level up to 28.73%. However, the longer process of steaming caused a significant decrease in polyphenol content and antioxidant activity. The hedonic test shows that the steaming treatment of coffee can increase preferences of panellists. There were two driving attributes that influence the overall liking of coffee, namely: bitterness and aftertaste. Coffee obtained from the treatment of 60 min steaming was most preferred by panellists. The results of APLSR biplot mapping show that there was a big change in almost all attributes in the coffee samples after 40 min steaming.
ARTICLE | doi:10.20944/preprints201806.0045.v1
Subject: Behavioral Sciences, Cognitive & Experimental Psychology Keywords: caffeine; cognition; motor coordination; memory; social behavior; mice
Online: 4 June 2018 (13:02:34 CEST)
Heavy caffeine consumption is associated with adverse health effects. The effects of moderate and high doses of caffeine mixed with drinking water on the motor coordination, learning and memory and the social behavior in mice were studied in mice. Animals were divided into 3 groups: control group, moderate dose group (Ac MD) and high dose group (Ac HD). The animals were tested after 7 days of caffeine administration. Rota rod test for motor coordination showed that the mice of the moderate dose group could stay more time on the rotating rod before they fall than the control group and the high dose group. Water maze test for learning and memory showed better performance of mice receiving moderate dose of caffeine compared to the other groups. Animals that were administered moderate as well as high doses of caffeine showed no sociability and no preference for social novelty in the three-chamber test used to test the social behavior. In elevated plus maze, control animals showed no anxiety- like behavior while mice administered with caffeine were both showing anxiety-like behaviors. We concluded that acute administration of moderate dose of caffeine to mice could enhance their spatial memory and motor coordination. High doses however caused defects in memory and learning. The social behavior as the level of anxiety and sociability was affected negatively by moderate as well as high dose caffeine administration.
REVIEW | doi:10.20944/preprints202112.0405.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: caffeine; attention deficit hyperactivity disorder; impulsivity; ADHD; animal models
Online: 24 December 2021 (11:34:52 CET)
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by a persistent pattern of inattention and/or hyperactivity-impulsivity. Neurobiologically, ADHD impairments arise from abnormalities in different circuits involving the prefrontal cortex. In face of high rates of diagnosis, alternative/complementary pharmacological therapeutic approaches for ADHD are needed. Although the number of publications that study the potential effects of caf-feine consumption on ADHD treatment have been accumulating over the last years, and caffeine has recently been used in ADHD research in the context of animal models, an updated evi-dence-based systematic review on the effects of caffeine on ADHD-like symptoms in animal stud-ies is missing. To provide insight and value at the preclinical level, a systematic review based on PRISMA guidelines was performed for all publications available up to September 1, 2021. Caffeine treatment increases attention, improves learning, memory and olfactory discrimination, without altering blood pressure and body weight. These results are supported at the neuronal level. Nonetheless, the implication of caffeine in modulating ADHD-like symptoms of hyperactivity and impulsivity is contradictory, raising discrepancies that require further clarification. Our results strengthen the hypothesis that caffeine cognitive effects found in animal models could be trans-lated to human ADHD, particularly during adolescence.
ARTICLE | doi:10.20944/preprints202011.0631.v1
Subject: Medicine & Pharmacology, Allergology Keywords: tension-type headache; migraine; neck and shoulder pain; ibuprofen; caffeine
Online: 25 November 2020 (10:51:30 CET)
As neck and/or shoulder pain (NSP) frequently occur together with tension-type headache (TTH) and migraine, we explored how concomitant NSP affects perceived treatment responses to an analgesic. An anonymous survey was performed among 895 TTH and migraine sufferers who used the analgesic 400 mg ibuprofen/100 mg caffeine. NSP was relatively abundant among patients (42.4% for TTH; 39.2% for migraine), and associated with >1 additional day with headache per month. Reported pain reduction was independent from NSP for TTH and migraine. More patients became pain-free at 2 h in migraine with NSP (42.9%) compared to migraine without NSP (32.2%), which is different from TTH with NSP (60.6%) and TTH without NSP (71.4%). For both, migraine and TTH, a recurrence of headache on the same day was more prevalent in those with concomitant NSP leading to a greater likelihood of taking a second dose of the analgesic. NSP frequently occurs together with TTH and migraine patients. In migraine, NSP seems to be associated with a better treatment response at 2 h. The more frequent recurrence of pain in those with concomitant NSP indicates that NSP makes both headache types worse. Further studies are needed to substantiate these effects.
REVIEW | doi:10.20944/preprints201808.0032.v1
Subject: Chemistry, Medicinal Chemistry Keywords: caffeine; methylxanthine; chlorogenic acid; caffeic acid; inflammation; antimutagen; anticancer; antioxidant
Online: 2 August 2018 (05:14:02 CEST)
Tea and coffee are the most commonly used beverages throughout the world. Both decoctions are rich in small organic molecules such as phenolics/polyphenolics, purine alkaloids, many methylxanthines, substituted benzoic and cinnamic acids. Many of these molecules are physiologically chemopreventive and chemoprotective agents against many severe conditions such as cancer, Alzheimer, Parkinsonism, inflammation, sleep apnea, cardiovascular disorders, bradycardia, fatigue, muscular relaxation, and oxidative stress. Caffeine, a purine alkaloid, is a common metabolite of both tea and coffee aqueous decoctions and its concentration in tea/coffee depends on the fermentation process, preparation of the water extract and quality of tea leaves/coffee beans. A 250 ml of a coffee cup contains 100-150 mg caffeine while the same volume of strong tea contains 25-40 mg caffeine. The present paper presents the potential of caffeine as a potent chemopreventive agent that can be used for numerous physiological disorders.
ARTICLE | doi:10.20944/preprints201707.0086.v1
Subject: Chemistry, Analytical Chemistry Keywords: Caffeine, Uncertainty calculation; ISO 17025, Guatemala coffee grains; GC-FID
Online: 28 July 2017 (13:05:43 CEST)
A simple method for the determination of caffeine in coffee grains by GC-FID is presented in the current work. The method was fully validated according to ISO 17025 requirements and European Commission regulation. The accuracy, as provided by recovery experiments was higher than 93%, and the precision, as provided by the (%)Relative standard deviation under reproducibility conditions, was lower than 5%. All independent parameters that lead in the increase of methods uncertainty were investigated. In the present work all special precautions were taken into account in order to avoid the use of an internal standard. The method was applied in real samples and possible health claims were investigated.
ARTICLE | doi:10.20944/preprints202209.0287.v1
Subject: Medicine & Pharmacology, Behavioral Neuroscience Keywords: Coffea arabica; antioxidant; acetylcholinesterase inhibition; catalepsy; unilateral 6-hydroxydopamine lesion; caffeine
Online: 20 September 2022 (03:22:27 CEST)
Epidemiologic studies suggest an inverse correlation between coffee consumption and the occurrence of neurodegenerative diseases, but the role of caffeine and roasting degree are still matter of debate. The objective of this work was to evaluate the effects of caffeinated (light, medium, and dark roast) and decaffeinated instant coffee samples in acetylcholinesterase inhibition and antioxidant assays, as well as in animal models of Parkinson’s disease. Caffeinated coffees inhibited the acetylcholinesterase in much smaller concentrations than decaffeinated coffee. All coffee samples showed antioxidant capacity without relation with the caffeine content. Dopaminergic-like activity in the haloperidol-induced catalepsy test was observed with caffeinated coffee, but not in the decaffeinated sample. The medium roast coffee reduced the number of rotations of rats after methamphetamine administration on the 6-hydroxydopamine unilateral lesion of the medial forebrain bundle. However, the coffee treatment did not avoid the loss of dopaminergic neurons on substantia nigra pars compact and only the smallest dose of coffee was able to avoid the decrease of dopamine levels in the lesioned side of the striatum. Altogether, these results suggest that coffee exerts moderate pro-cholinergic and pro-dopaminergic effects and caffeine seems to be the main responsible for these effects.
REVIEW | doi:10.20944/preprints202012.0559.v1
Subject: Medicine & Pharmacology, Allergology Keywords: sports cardiology; athlete; caffeine; anabolic steroids; heart disease; cardiac magnetic resonance imaging
Online: 22 December 2020 (12:39:52 CET)
Several performance-enhancing or ergogenic drugs have been linked to both significant adverse cardiovascular effects and increased cardiovascular risk. Even with increased scrutiny on the governance of performance-enhancing drugs (PEDs) in professional sport and heightened awareness of the associated cardiovascular risk, there are some who are prepared to risk their use to gain competitive advantage. Caffeine is the most commonly consumed drug in the world and its ergogenic properties have been reported for decades. Thus, the removal of caffeine from the World Anti-Doping Agency (WADA) list of banned substances, in 2004, has naturally led to an exponential rise in its use amongst athletes. The response to caffeine is complex and influenced by both genetic and environmental factors. Whilst the evidence may be equivocal, the ability of an athlete to train longer or at a greater power output cannot be overlooked. Furthermore, its impact on the myocardium remains unanswered. In contrast, anabolic steroids are recognised PEDs that improve athletic performance, increase muscle growth and suppress fatigue. Their use, however, comes at a cost, afflicting the individual with several side effects, including those that are detrimental to the cardiovascular system. This review addresses the effects of the two commonest PEDs, one legal, the other prohibited, and their respective effects on the heart, as well as the long-term implications.
COMMUNICATION | doi:10.20944/preprints201908.0192.v1
Subject: Chemistry, Applied Chemistry Keywords: caffeine; colloidal coffee; optical absorption; pH sensor; solute-solvent interactions; UV absorber
Online: 19 August 2019 (04:14:30 CEST)
Coffee and caffeine have been used as solar absorbers and also to increase the thermal stability and efficiency of perovskite solar cells. In this work, we report the sensing of extremely alkaline pH by colloidal coffee solution aided by generation of an optical absorption band in the near-UV region. This generation of absorption band could be explained by the orientation induced dipole-dipole interactions arising from differing caffeine-solvent interactions with varying pH. Such a generation leads to the lowering of direct as well as indirect bandgaps from 4 eV-->2.8 eV& 3.4 eV-->2.5 eV, respectively. We also estimate the changes in optical energy storage efficiency, inferring it to be highest for pH 11 having the highest intensity of the generated absorption band (λ_abs≈360 nm). With these observations and further deductions, the work reported in this paper would be of immense interest to the researchers working in the field of development of chemical pH sensors and also in the development of novel UV absorbers.
ARTICLE | doi:10.20944/preprints201807.0469.v1
Subject: Materials Science, Nanotechnology Keywords: caffeine; nitrogen-doping; graphene; nanowires; functionalization; pyridinic; monolayer; synthesis; carbon nanostructures; nanomaterials
Online: 25 July 2018 (06:10:43 CEST)
In this work, we propose an easy and a low cost method for the synthesis of Nitrogen-Doped Graphene NDG and its silver nanowires NW functionalization NWGN. The synthesis was performed using the improved graphene oxide method, chemical reduction of graphene oxide in the presence of caffeine as green nitrogen source and the subsequently the silver nanowires growth in the surface, by the chemical reductions salts in the presence of NG. Achieving a homogeneous growing (coating) of graphene sheets. The samples were analyzed using conventional characterization techniques: SEM-EDX, XRD, FT-IR, RAMAN, TEM, HRTEM, STEM and XPS.
REVIEW | doi:10.20944/preprints201807.0467.v1
Subject: Medicine & Pharmacology, Obstetrics & Gynaecology Keywords: caffeine; coffee; epidemiology; recall bias; misclassification; residual confounding; reverse causation; publication bias
Online: 25 July 2018 (05:57:48 CEST)
Consumption of coffee by women early in their pregnancy has been viewed as potentially increasing the risk of miscarriage, low birth weight, and childhood leukemias. Many of these reports of epidemiologic studies have not acknowledged the potential biases inherent in studying the relationship between early-pregnancy-coffee consumption and subsequent events. I discuss five of these biases, recall bias, misclassification, residual confounding, reverse causation, and publication bias. Each might account for claims that attribute adversities to early-pregnancy-coffee consumption. To what extent these biases can be avoided remains to be determined. At a minimum, they need to be acknowledged wherever they might account for what is reported.
REVIEW | doi:10.20944/preprints202212.0138.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Spent coffee grounds; SCG Briquettes; SCG Biodiesel; Caffeine; Residual Oil; Irregular Particle Size
Online: 8 December 2022 (01:42:06 CET)
Coffee is regarded as the highly consumed beverage throughout the world and has established a key spot in the world economy as an important commodity for trading. In general, they are produced by brewing their roasted and ground beans, which release aromatic coffee; as well as produce an equivalent amount of spent coffee grounds (SCG). Previously, they were discarded as wastes or used as natural pest repellent or garden fertilizer; however, in recent times, are valorized into biofuels owing to their high calorific value. In fact, SCG briquettes have gained wide attention for supplying energy renewably, especially to the rising energy demand; and also have been identified as an effective measure to reduce their pollution. With this in mind, this present chapter focuses on reviewing the availability and chemistry involved in these SCG wastes, pre-treatments and preparations required for their briquetting, compacting techniques followed, and fuel characteristics of their briquettes, from various available works of literature. Here, their availability showcases the amount of SCG wastes generated with respect to time and consumption, wherein understanding their chemistry helps in deciding the pre-treatments necessary for their briquetting. Meanwhile, preparation techniques briefs about the necessary pre-treatments undertaken before compaction by different researchers; and the fuel characteristics define the physicochemical and mechanical properties of their briquettes, developed using various compaction methods. Besides, combustion behaviors of these briquettes are explained in terms of their burning characteristics and emission levels, as reported in literatures; which help in deciding their suitability as a replacement for existing fossil coal. Eventually, all the reported data were in accordance with their permissible standards and suggested these SCG as a highly renewable solid biofuel.
ARTICLE | doi:10.20944/preprints202206.0321.v1
Subject: Chemistry, Food Chemistry Keywords: coffee leaf tea; novel food; coffee by-products; Coffea arabica; caffeine; epigallocatechin gallate
Online: 23 June 2022 (09:22:46 CEST)
The production of coffee leaf tea (Coffea arabica) in El Salvador and the influences of processing steps on non-volatile compounds and volatile aroma-active compounds were investigated. The tea was produced according to process steps of conventional tea (Camellia sinensis) with available possibilities on the farm. Influencing factors were the leaf type (old, young, yellow, shoots), processing (blending, cutting, rolling, freezing, steaming), drying (sun drying, oven drying, roasting) and fermentation (wild, yeast, Lactobacillus). Subsequently, the samples were analysed for the maximum levels of caffeine, chlorogenic acid, and epigallocatechin gallate permitted by the European Commission. The caffeine content varied between 0.37 g/100 g dry mass (DM) and 1.33 g/100 g DM, the chlorogenic acid between not detectable and 9.35 g /100 g DM and epigallocatechin gallate could not be detected at all. Furthermore, water content, essential oil, ash content, total polyphenols, total catechins, organic acids, and trigonelline were determined. Gas chromatography—mass spectrometry-olfactometry and calculating of the odour activity values (OAVs) were carried out to determine the main aroma-active compounds, which are β-ionone (honey-like, OAV 132-927), decanal (citrus-like, floral, OAV 14-301), α-ionone (floral, OAV 30-100), (E,Z)-2,6-nonadienal (cucumber-like, OAV 18-256), 2,4-nonadienal (melon-like, OAV 2-18), octanal (fruity, OAV 7-23), (E)-2 nonenal (citrus-like, OAV 1-11), hexanal (grassy, OAV 1-10), and 4-heptenal (green, OAV 1-9).
ARTICLE | doi:10.20944/preprints201911.0390.v1
Subject: Chemistry, Food Chemistry Keywords: caffeine; 16-O-methylcafestol; kahweol; furfuryl alcohol; tetramethylsilan (TMS); magnetic resonance spectroscopy; validation studies
Online: 30 November 2019 (10:20:17 CET)
Monitoring coffee quality as a means of detecting and preventing economically motivated fraud is an important aspect of international commerce today. Therefore, there is a compelling need for rapid high throughput validated analytical techniques such as quantitative proton NMR spectroscopy for screening and authenticity testing. For this reason, we sought to validate an NMR spectroscopic method for routine screening of coffee for quality and authenticity. A factorial experimental design was used to investigate the influence of NMR device, extraction time and nature of coffee on the content of caffeine, 16-O-methylcafestol (OMC), kahweol, furfuryl alcohol and 5-hydroxymethylfurfural (HMF) in coffee. The method was successfully validated for specificity, selectivity, sensitivity and linearity of detector response. The proposed method produced satisfactory precision for all analytes in roasted coffee, except for kahweol in canephora (robusta) coffee. The proposed validated method may be used for routine screening of roasted coffee for quality and authenticity control, as its applicability was demonstrated during the recent OPSON VIII Europol-Interpol operation on coffee fraud control.