Controlling for caffeine in cardiovascular research: A critical review

Comparative Impact of Organic Grass-Fed and Conventional Cattle-Feeding Systems on Beef and Human Postprandial Metabolomics-A Randomized Clinical Trial

BACKGROUND/OBJECTIVES

Cattle-feeding systems may have health implications for consumers of beef products. Organic grass-fed (GRA) and conventional (CON) cattle-feeding systems may result in beef products with differing metabolite profiles and therefore could impact the postprandial metabolomic response of consumers. This study aims to measure whole beef metabolomics and postprandial metabolomic response of consumers between GRA and CON beef to elucidate potential health implications.

METHODS

This study followed a randomized double-blind crossover design with healthy male and female subjects (n = 10). Plasma samples were taken at fasting (0) and postprandially for four hours after consumption of a steak from each condition. Untargeted metabolomic analysis of whole beef and human plasma samples used LC/MS. Multivariate and pathway enrichment analysis in MetaboAnalyst was used to investigate metabolite and biochemical pathways that distinguished CON and GRA.

RESULTS

Cattle-feeding systems impacted both postprandial and whole beef steak metabolomic profiles. Metabolites that contributed to this variation included carnitine species (Proionylcarnitine), fatty acids, amino acids (L-valine), and Calamendiol. These metabolites have been associated with oxidative stress, inflammation, and cardiovascular health. Functional pathway enrichment analysis revealed numerous amino acid degradation pathways, especially branched-chain amino acids, and fatty acid degradation that changed throughout the postprandial time course.

CONCLUSIONS

These findings suggest that CON and GRA cattle-feeding systems differentially impact whole beef metabolomics, as well as consumer postprandial metabolic responses and the associated health implications.

Publication guidelines for human heart rate and heart rate variability studies in psychophysiology-Part 1: Physiological underpinnings and foundations of measurement

This Committee Report provides methodological, interpretive, and reporting guidance for researchers who use measures of heart rate (HR) and heart rate variability (HRV) in psychophysiological research. We provide brief summaries of best practices in measuring HR and HRV via electrocardiographic and photoplethysmographic signals in laboratory, field (ambulatory), and brain-imaging contexts to address research questions incorporating measures of HR and HRV. The Report emphasizes evidence for the strengths and weaknesses of different recording and derivation methods for measures of HR and HRV. Along with this guidance, the Report reviews what is known about the origin of the heartbeat and its neural control, including factors that produce and influence HRV metrics. The Report concludes with checklists to guide authors in study design and analysis considerations, as well as guidance on the reporting of key methodological details and characteristics of the samples under study. It is expected that rigorous and transparent recording and reporting of HR and HRV measures will strengthen inferences across the many applications of these metrics in psychophysiology. The prior Committee Reports on HR and HRV are several decades old. Since their appearance, technologies for human cardiac and vascular monitoring in laboratory and daily life (i.e., ambulatory) contexts have greatly expanded. This Committee Report was prepared for the Society for Psychophysiological Research to provide updated methodological and interpretive guidance, as well as to summarize best practices for reporting HR and HRV studies in humans.

Caffeine: a potential mechanism for anti-obesity

Obesity refers to the excessive accumulation of fat caused by a long-term imbalance between energy intake (EI) and energy expenditure (EE). Over recent years, obesity has become a major public health challenge. Caffeine is a natural product that has been demonstrated to exert anti-obesity effects; however, the mechanisms responsible for the effect of caffeine on weight loss have yet to be fully elucidated. Most obesity-related deaths are due to cardiovascular disease. Recent research has demonstrated that caffeine can reduce the risk of death from cardiovascular disease; thus, it can be hypothesized that caffeine may represent a new therapeutic agent for weight loss. In this review, we synthesize data arising from clinical and animal studies over the last decade and discuss the potential mechanisms by which caffeine may induce weight loss, focusing particularly on increasing energy consumption, suppressing appetite, altering lipid metabolism, and influencing the gut microbiota. Finally, we summarize the major challenges associated with caffeine and anti-obesity research and highlight possible directions for future research and development.

Noise annoys-But personal choice can attenuate noise effects on cardiac response reflecting effort

Since personal choice fosters commitment and shields action execution against potentially conflicting influences, two laboratory experiments with university students (N = 228) tested whether engaging in action by personal choice versus external assignment of task characteristics moderates the effect of irrelevant acoustic noise on cardiovascular responses reflecting effort. Participants who could personally choose the stimulus color of moderately difficult cognitive tasks were expected to be shielded against the irrelevant noise. By contrast, when the stimulus color was externally assigned, we predicted receptivity for the irrelevant noise to be high. As expected, in both experiments, participants in the assigned color condition showed stronger cardiac pre-ejection period reactivity during task performance when exposed to noise than when working in silence. On the contrary, participants who could choose the stimulus color were shielded against the noise effect on effort. These findings conceptually replicate and extend research on the action shielding effect by personal choice and hold practical implications for occupational health.

Change in Caffeine Consumption after Pandemic (CCAP-Study) among University Students: A Cross-Sectional Study from Italy

(1) Background: The lockdown, imposed to limit the pandemic evolution, impacted the social habits and lifestyle of inhabitants also from many countries other than Italy. Caffeine consumption could be a useful option to improve mood, as the lockdown strongly affected mental health, particularly increasing anxiety and sleep disorders. (2) Methods: It was a cross-sectional study aimed to evaluate the change in caffeine consumption after the pandemic period in a sample of Italian University students. It investigated coffee and products containing caffeine consumption, the anxiety level by State Trait Anxiety Inventory (STAI) and sleep quality with the Insomnia Severity Index (ISS). (3) Results: A total of 404 participants were enrolled in the study. During the lockdown period, 23% of subjects consumed more coffee compared to the pre-pandemic period. Daily coffee consumption also changed after the lockdown period compared to the pre-pandemic period, with 36.1% of subjects that increased their consumption. Comparing other caffeine-based products, energizing supplement consumption showed a greater increase after the lockdown period than energy drinks. Regarding anxiety, subjects who reported increased coffee consumption reported higher STAI scores and ISS. (4) Conclusions: About a quarter of university students increased their consumption of caffeine-based products after the pandemic, reporting higher levels of anxiety and poor sleep quality.

Valorization of baobab seeds (Adansonia digitata) as a coffee-like beverage: evaluation of roasting time on bioactive compounds

The baobab tree (Adansonia digitata) can be found in sub-Saharan Africa, and its fruit presents high nutritional value. However, baobab seeds are often discarded and their potential remains underutilized. This study aimed to investigate the effect of roasting time (30/55/80/105 min at 200 °C) on the physical-chemical properties of baobab seeds and the bioactive compounds in a coffee-like beverage. The results showed a decrease in moisture, Aw (water activity), and hardness of baobab seeds with increasing roasting time. These changes resulted from moisture loss, caramelization, and Maillard reactions, which also affected appearance when compared with unroasted baobab seeds. The pH of the beverage decreased to a value of around 6.01 after 105 min of roasting. The total phenolic content and antioxidant activity of the beverage increased with roasting time, reaching 851.2 mg GAE/100 g (after 80 min) and 18.9 mmol Fe2+/100 g (after 55 min), respectively. The caffeine content remained stable around 16 mg/100 g from 55 to 105 min, lower than that of unroasted coffee beans and decaffeinated coffee. These findings suggest the potential for valorizing baobab seeds in the development of a new coffee-like beverage with lower caffeine content.

Caffeine intake in adults with cardiovascular diseases; A cross-sectional study

Background: Caffeine in the safe dose range has been associated with a reduction in the risk of chronic diseases. There is evidence that caffeine intake has both protective and negative effects on cardiovascular diseases. Aim: This study aimed to investigate caffeine intake in cardiovascular patients. Methods: The study sample was selected from individuals who applied to the Cardiology policlinic of Tekirdağ Namık Kemal University Hospital. A questionnaire was applied using face-to-face interview method to determine their demographic information, nutritional status and anthropometric measurements. Moreover, the nutritional status of the participants was determined by the Food Frequency Questionnaire and the type of cardiovascular disease was determined by a physician. The blood parameters of the sample for the last three months were questioned. The sample has been ninety people of whom fifty cardiovascular diseases (CVDs) were diagnosed and forty were non-diagnosed (ND). Results: The mean age of individuals (n = 90) was 43.2 ± 14.4. The BMI and waist circumference of the CVDs group were statistically significantly higher than the ND group (p < 0.001). While the total caffeine consumption of the ND group was 209.34 ± 143.85 mg/day, consumption of the CVDs group was 209.99 ± 196.76 mg/day. LDL cholesterol and total cholesterol did not show statistically significant difference between the two groups. However, HDL cholesterol was significantly higher in the ND group (p ≤ 0.001). Conclusion: Present results show that daily caffeine consumption may partially affect blood parameters associated with cardiovascular diseases, especially in the presence of coronary artery disease.

Dietary caffeine intake is associated with favorable metabolic profile among apparently healthy overweight and obese individuals

BACKGROUND

Recent studies have revealed some conflicting results about the health effects of caffeine. These studies are inconsistent in terms of design and population and source of consumed caffeine. In the current study, we aimed to evaluate the possible health effects of dietary caffeine intake among overweight and obese individuals.

METHODS

In this cross-sectional study, 488 apparently healthy individuals with overweight and obesity were participated. Dietary intake was assessed by a Food Frequency Questionnaire (FFQ) and the amount of dietary caffeine was calculated. Body composition was determined by bioelectrical impedance analysis (BIA). Enzymatic methods were used to evaluate serum lipid, glucose, and insulin concentrations.

RESULTS

Those at the highest tertile of dietary caffeine intake had lower percentage of fat mass, higher fat free mass and appetite score (P < 0.05). Also, lower total cholesterol (TC) and low density lipoprotein cholesterol (LDL-c) was observed in higher tertiles of dietary caffeine intake compared with lower tertiles. In multinomial adjusted models, those at the second tertile of dietary caffeine intake were more likely to have higher serum insulin (P = 0.04) and lower homeostatic model assessment of insulin resistance (HOMA-IR) values compared with first tertile (P = 0.03) in crude model. While, in the age, body mass index (BMI), sex, physical activity, socio-economic status (SES) and energy intake -adjusted model (Model III), those at the third tertile of dietary caffeine intake were more likely to have low serum LDL concentrations [odds ratio (OR) = 0.957; CI = 0.918-0.997; P = 0.04]. With further adjustment to dietary vegetable, fiber and grain intake, those at the third tertile of dietary caffeine intake were more likely to have low systolic blood pressure (SBP), LDL and high HDL levels compared with those at the first tertile (P < 0.05).

CONCLUSION

High intakes of dietary caffeine was associated with lower LDL, SBP, insulin resistance and higher HDL concentrations among overweight and obese individuals. However, due to observational design of the study, causal inference is impossible and further studies are warranted to confirm our findings.

Can personal task choice shield against fear and anger prime effects on effort? A study on cardiac response

This experiment tested whether personal task choice can shield against implicit affective influences on sympathetically mediated cardiovascular response, reflecting effort. Participants were N = 121 healthy university students who completed a moderately difficult memory task with integrated briefly flashed and masked fear vs. anger primes. Half of the participants believed they could choose between an attention and a memory task, while the other half was automatically assigned to the task. Replicating previous research, we expected an influence of the affect primes on effort when the task was externally assigned. By contrast, when participants were given a task choice, we predicted strong action shielding and thus a weak implicit affect effect on resource mobilization. As expected, participants in the assigned task condition showed stronger cardiac pre-ejection period reactivity when exposed to fear primes than when processing anger primes. Importantly, this affect prime effect disappeared when participants could ostensibly choose the task. These findings add to other recent evidence for action shielding by personal task choice and importantly extend this effect to implicit affective influences on cardiac reactivity during task performance.

Changes in health-related lifestyle choices of university students before and during the COVID-19 pandemic: Associations between food choices, physical activity and health

The COVID-19 pandemic has had a profound effect on our lives and society, influencing both individuals' lifestyles and habits. Recent research shows that anxiety and loneliness have continued to rise, along with changes in food and lifestyle choices. The aim of the study was to investigate whether the pandemic influenced food choices and consumption of energy drinks, alcohol, fruits, and vegetables among first-year university students. Additionally, assessing the relationship between mental and physical health, physical activity, and food choices. A total of 128 male and 128 female first-year students at the University of Iceland were invited to answer an electronic questionnaire in January and early February 2021. A total of 118 students (54% men) participated in the study and valid answers were 115 (46% participation rate). Almost half of the students (44%) experienced that their food choices had worsened, while 14% reported an improvement, compared to before the pandemic. Consumption of caffeinated beverages increased for 26% of students, while 19% experienced a decrease. Just over half of the students reported not drinking alcohol (13%) or reduced consumption (41%). Participants who reported that their mental health had deteriorated or remained the same tended to spend less time on physical activity and experienced worsened food choices (p<0.05). Similarly, those who spent less or the same time on physical activity estimated that their food choices had deteriorated (p<0.05). The COVID-19 pandemic has had a significant impact on the lifestyles of university students and this study has revealed how lifestyle choices and mental health seem to be highly affected by one another. Additionally, the potentially harmful effects of excessive intake of energy drinks need to be enhanced. Interestingly, about 40% of the respondents in the current study drank less alcohol during the pandemic than prior to the pandemic, indicating a strong relationship between alcohol drinking and social gatherings. This study reveals the importance of educating young people on healthy lifestyle choices and the importance of mental health needs to be emphasised.

How Long Is Long Enough? Controlling for Acute Caffeine Intake in Cardiovascular Research

Caffeine substantially affects cardiovascular functioning, yet wide variability exists in caffeine control procedures in cardiovascular reactivity research. This study was conducted in order to identify a minimal abstention duration in habitual coffee consumers whereby cardiovascular reactivity is unconfounded by caffeine; Six hours (caffeine's average half-life) was hypothesized. Thirty-nine subjects (mean age: 20.9; 20 women) completed a repeated measures study involving hand cold pressor (CP) and memory tasks. Caffeinated and decaffeinated coffee were administered. The following cardiovascular indices were acquired during pre-task, task, and post-task epochs prior to coffee intake, 30 min-, and six hours post-intake: Heart rate (HR), high-frequency heart rate variability (HF-HRV), root mean squared successive differences (RMSSD), systolic and diastolic blood pressures (SBP, DBP), mean arterial pressure (MAP), pre-ejection period (PEP), left ventricular ejection time (LVET), systemic vascular resistance (SVR), systemic vascular resistance index (SVRI). Results support the adequacy of a six-hour abstention in controlling for caffeine-elicited cardiovascular changes. The current study offers a suggested guideline for caffeine abstention duration in cardiovascular research in psychophysiology. Consistent practice in caffeine abstention protocols would promote validity and reliability across such studies.

Examining the potential of VR program Tilt Brush in reducing anxiety

Recent advancement in technology has made virtual reality (VR) more accessible and immersive than ever before, resulting in its increasing utility in various industries. Despite this, VR has remained an underutilised tool within clinical psychology. This study aimed to explore the potential of using VR for therapeutic benefits through examining the level of flow and anxiety-reducing effects of freeform drawing in real life (on paper) versus drawing in VR (using Tilt Brush) via a randomised-controlled trial with 40 participants. State and trait anxiety was measured using the State-Trait Anxiety Inventory, level of flow was measured using the Long Flow State Scale, and level of presence was measured using the iGroup Presence Questionnaire. Overall level of flow was not significantly different between both groups, implying drawing in VR induces as much flow as drawing in real life. Level of flow was positively correlated to level of presence experienced in the VR group (p < .01). Although there was no significant interaction effect, both groups experienced an overall decrease in state anxiety, with the VR group experiencing a significant reduction of state anxiety from pre- to post-test (p < .01).

Caffeine. A critical review of contemporary scientific literature

Caffeine is a secondary metabolite extensively studied for its stimulatory properties and presumed association with specific pathologies. This alkaloid is typically consumed through coffee, tea, and other plant products but is also an additive in many medications and confectionaries. Nonetheless, despite its worldwide consumption and acceptance, there is controversial evidence as to whether its effects on the central nervous system should be interpreted as stimulatory or as an addiction in which typical withdrawal effects are canceled out with its daily consumption. The following discussion is the product of an extensive review of current scientific literature, which aims to describe the most salient topics associated with caffeine's purpose in nature, biosynthesis, metabolism, physiological effects, toxicity, extraction, industrial use and current plant breeding approaches for the development of new caffeine deficient varieties as a more economical option to the industrially decaffeinated coffees currently available to caffeine intolerant consumers. Keywords: biosynthesis, decaffeination, extraction, metabolism, physiological effects, plant breeding.

Automated Detection of Caffeinated Coffee-Induced Short-Term Effects on ECG Signals Using EMD, DWT, and WPD

The effect of coffee (caffeinated) on electro-cardiac activity is not yet sufficiently researched. In the current study, the occurrence of coffee-induced short-term changes in electrocardiogram (ECG) signals was examined. Further, a machine learning model that can efficiently detect coffee-induced alterations in cardiac activity is proposed. The ECG signals were decomposed using three different joint time-frequency decomposition methods: empirical mode decomposition, discrete wavelet transforms, and wavelet packet decomposition with varying decomposition parameters. Various statistical and entropy-based features were computed from the decomposed coefficients. The statistical significance of these features was computed using Wilcoxon's signed-rank (WSR) test for significance testing. The results of the WSR tests infer a significant change in many of these parameters after the consumption of coffee (caffeinated). Further, the analysis of the frequency bands of the decomposed coefficients reveals that most of the significant change was localized in the lower frequency band (<22.5 Hz). Herein, the performance of nine machine learning models is compared and a gradient-boosted tree classifier is proposed as the best model. The results suggest that the gradient-boosted tree (GBT) model that was developed using a db2 mother wavelet at level 2 decomposition shows the highest mean classification accuracy of 78%. The outcome of the current study will open up new possibilities in detecting the effects of drugs, various food products, and alcohol on cardiac functionality.

Does coffee, tea and caffeine consumption reduce the risk of incident breast cancer? A systematic review and network meta-analysis

OBJECTIVE

We aimed to evaluate the association between coffee and/or tea consumption and breast cancer (BC) risk among premenopausal and postmenopausal women and to conduct a network meta-analysis.

DESIGN

Systematic review and network meta-analysis.

SETTING

We conducted a systematic review of electronic publications in the last 30 years to identify case-control studies or prospective cohort studies that evaluated the effects of coffee and tea intake.

RESULTS

Forty-five studies that included more than 3 323 288 participants were eligible for analysis. Network meta-analysis was performed to determine the effects of coffee and/or tea consumption on reducing BC risk in a dose-dependent manner and differences in coffee/tea type, menopause status, hormone receptor and the BMI in subgroup and meta-regression analyses. According to the first pairwise meta-analysis, low-dose coffee intake and high-dose tea intake may exhibit efficacy in preventing ER(estrogen receptor)- BC, particularly in postmenopausal women. Then, we performed another pairwise and network meta-analysis and determined that the recommended daily doses were 2-3 cups/d of coffee or ≥5 cups/d of tea, which contained a high concentration of caffeine, particularly in postmenopausal women.

CONCLUSIONS

Coffee and tea consumption is not associated with a reduction in the overall BC risk in postmenopausal women and is associated with a potentially lower risk of ER- BC. And the highest recommended dose is 2-3 cups of coffee/d or ≥5 cups of tea/d. They are potentially useful dietary protectants for preventing BC.

Retinoic Acid Signaling Plays a Crucial Role in Excessive Caffeine Intake-Disturbed Apoptosis and Differentiation of Myogenic Progenitors

Whether or not the process of somitogenesis and myogenesis is affected by excessive caffeine intake still remains ambiguous. In this study, we first showed that caffeine treatment results in chest wall deformities and simultaneously reduced mRNA expressions of genes involved in myogenesis in the developing chicken embryos. We then used embryo cultures to assess in further detail how caffeine exposure affects the earliest steps of myogenesis, and we demonstrated that the caffeine treatment suppressed somitogenesis of chicken embryos by interfering with the expressions of crucial genes modulating apoptosis, proliferation, and differentiation of myogenic progenitors in differentiating somites. These phenotypes were abrogated by a retinoic acid (RA) antagonist in embryo cultures, even at low caffeine doses in C2C12 cells, implying that excess RA levels are responsible for these phenotypes in cells and possibly in vivo. These findings highlight that excessive caffeine exposure is negatively involved in regulating the development of myogenic progenitors through interfering with RA signaling. The RA somitogenesis/myogenesis pathway might be directly impacted by caffeine signaling rather than reflecting an indirect effect of the toxicity of excess caffeine dosage.

Paenibacillus polymyxa biofertilizer application in a tea plantation reduces soil N2O by changing denitrifier communities

Increasing the use of nitrogen fertilizers in tea orchards has led to intense nitrous oxide (N₂O) emissions. Foliar application of Paenibacillus polymyxa biofertilizer has been proven to be beneficial for organic tea production. In this study, tea yield and quality were significantly improved after application of P. polymyxa biofertilizer compared with the control but were not significantly different from chemical fertilizer treatments. However, the average N₂O fluxes in tea fields treated with chemical fertilizers and biofertilizers (225 kg N·ha^-1·year^-1 for both) were 50.6-973.7 and 0.6-29.1 times higher than those in the control treatment, respectively. Pot experiments conducted to explore the mechanism of N₂O reduction induced by P. polymyxa biofertilizer showed that applying P. polymyxa in addition to urea could reduce N₂O fluxes by 36.5%-73.1%. Quantitative PCR analysis suggested that a significant increase in the quantity of nirK and nosZ genes was linked to the reduction of N₂O, and high-throughput sequencing of nosZ revealed active and potentially efficient denitrifiers in different treatments. Our findings suggest that P. polymyxa biofertilizer is in line with the requirements of modern agriculture, which aims to increase product yield and quality while reducing negative environmental impacts.

Caffeine and blood pressure: a critical review perspective

The WHO reported that high blood pressure (BP) is one of the primary causes of death worldwide. Hypertension (HPT) is a major risk factor for CVD and related diseases as well as for diseases, leading to a considerable increase in cardiovascular risk. Since BP response could also be influenced by caffeine, which is widely consumed with coffee and other items, it is important to define the possible effects associated with caffeine intake. The most recent findings aimed at clarifying the role of caffeine consumption on BP and HPT risk/incidence are conflicting and difficult to interpret. Therefore, in the present narrative review, we aimed to examine various methodological inaccuracies/aspects and factors that make studies difficult to be compared, in order to obtain a single consensus on the effects of caffeine intake on the risk of BP and HPT. We observed that this heterogeneity in results could be due to the presence of: (i) several variables affecting BP (such as age, sex, genetic and lifestyle aspects); (ii) different caffeine content of food and beverages; and (iii) caffeine metabolism. Moreover, different methodological aspects in the evaluation of daily dietary caffeine intake and in the BP measurement could add some other bias in the interpretation of results. Therefore, it is mandatory to consider all methodological aspects and confounding factors to generate a standardised methodology in order to increase cross-study consistency and minimise confounding effects of different variables on the relationship between BP response and HPT risk/incidence after caffeine intake.