Caffeine Intake and Its Sex-Specific Association with General Anxiety: A Cross-Sectional Analysis among General Population Adults

Acute, dose-response effects of guayusa leaf extract on mood, cognitive and motor-cognitive performance, and blood pressure, heart rate, and ventricular repolarization

PURPOSE

We conducted a randomized, double-blind, placebo-controlled crossover trial in young adults to examine the dose-dependent (600 mg versus 1200 mg), acute effects of consumption of an Ilex guayusa tea extract (GLE) on mood, cognitive and motor-cognitive performance, as well as its acute cardiovascular effects.

METHODS

Twenty-five adults (mean ± SD, age = 28 ± 7 y; 9 M/16 F) completed familiarization and then three randomly ordered experimental visits where they consumed either 600 mg (GLE600) or 1200 mg (GLE1200) GLE or placebo (PLA). Following supplement consumption, participants completed a mood state survey, assessments of perceived jitteriness, energy, and focus, and neurocognitive and motor-cognitive testing. Blood pressure (BP), heart rate, and QT interval length were determined before and after supplementation.

RESULTS

GLE600 significantly improved total mood disturbance (mean ± SE difference = -6.9 ± 2.6 au, p = 0.034), fatigue-inertia (-2.84 ± 0.89 au, p = 0.008), perceived energy (+13.00 ± 4.49 au; p = 0.02), motor speed (+4.52 ± 1.42 au, p = 0.008), and psychomotor speed (+7.20 ± 2.16 au, p = 0.005) relative to PLA. GLE1200 also improved psychomotor speed (+5.08 ± 2.16 ms, p = 0.045) and uniquely increased motor-cognitive performance as reflected by a decrease in reaction time (-0.106 ± 0.04 ms, p = 0.026) during a neurocognitive hop test. The effect of GLE on jitteriness was both dose- and sex-dependent. Jitteriness increased with increasing GLE dose in women only (p < 0.001). Both GLE600 and GLE1200 similarly increased systolic and diastolic BP by 4-5 mmHg (p ≤ 0.022). Neither GLE600 nor GLE1200 acutely influenced QTc length (p = 0.31).

CONCLUSIONS

The goal of GLE supplementation should be considered when selecting a dosing strategy. Lower dosages of GLE (e.g. 600 mg) appear to optimize cognitive and mood-related outcomes while limiting side-effects such as jitteriness in women, and higher dosages may be necessary (e.g. 1200 mg) to promote improvements in motor-cognitive performance.

Maternal low-dose caffeine intake during the perinatal period promotes short- and long-term sex-dependent hormonal and behavior changes in the offspring

AIM

Maternal caffeine crosses the placenta and mammary barriers, reaching the baby and, because his/her caffeine metabolism is immature, our hypothesis is that even a low caffeine intake (250 mg/day), lower than the dose limit recommended by the World Health Organization, can promote caffeine overexposure in the offspring, leading to short- and long-term changes.

MAIN METHODS

Pregnant Wistar rats received intragastric caffeine (CAF) (25 mg/Kg/day) or vehicle during the gestation and lactation periods. We evaluated morphometrical, metabolic, hormonal, and behavioral parameters of male and female offspring at different ages.

KEY FINDINGS

Even a low caffeine intake promoted lower maternal body mass and adiposity, higher plasma cholesterol and lower plasma T3, without changes in plasma corticosterone. Female CAF offspring exhibited lower birth weight, body mass gain and food intake throughout life, and hyperinsulinemia at weaning, while male CAF offspring showed reduced food intake and lower plasma T3 at weaning. At puberty and adulthood, male CAF showed higher preference for palatable food, aversion to caffeine intake and higher locomotor activity, while female CAF only showed lower preference for high fat diet (HFD) and lower anxiety-like behavior. At adulthood, both male and female offspring showed higher plasma T3. Male CAF showed hypertestosteronemia, while female CAF showed hypoinsulinemia without effect on glucose tolerance.

SIGNIFICANCE

A low caffeine intake during the perinatal period affects rat's offspring development, promoting sex-dependent hormonal and behavior changes. Current data suggest the need to review caffeine recommendations during the perinatal period.

Demographic Differences in Insomnia and Anxiety and the Association with Cardiovascular Risk Factors among Jordanian Healthy Adult

Background

Prior studies showed that anxiety and insomnia are both associated with Cardiovascular Disease (CVD). There is a lack of literature related to the prevalence of insomnia and anxiety among healthy adult populations in developing countries as in Jordan, Therefore, this study aimed to examine the association between the CVD risk factors and both insomnia and anxiety among healthy adults had one or more modifiable CVD risk factors.

Materials and Methods

A cross-sectional method was used to examine the prevalence of anxiety, insomnia, and demographical and clinical association with anxiety and insomnia among 1000 Jordanian adult participants using the Hamilton Anxiety Rating Scale and the insomnia severity index. Pearson's correlation was used to examine the correlation between anxiety and insomnia scores. Linear regression was used to examine predictors to anxiety and insomnia based on demographical and clinical details.

Results

The result of the current study showed that (30.20%) of participants had higher anxiety scores, (29.70%) had moderate to severe insomnia. Moreover, there was a significant positive correlation between anxiety and insomnia scores, p = 0.01. Based on the current study findings only marital status and anxiety were unique predictors of insomnia F(14,45) = 989, p = 0.001. Moreover, Predictors of anxiety were gender, hypertension, Diabetes mellitus, dyslipidemia, and insomnia F(19,89) = 989, p = 0.001.

Conclusions

Sleep and psychological well-being are important components of an adult's health and well-being. The study showed that marital status and anxiety are predictors of insomnia. Whereas, gender, hypertension, diabetes mellitus, dyslipidemia, and insomnia were predictors of anxiety. This study highlights the importance of the implementation of a primary prevention strategy for individuals with modifiable CVD risk factors to reduce anxiety and insomnia levels among adults.

Effects of Different Caffeine Dosages on Maximal Physical Performance and Potential Side Effects in Low-Consumer Female Athletes: Morning vs. Evening Administration

While previous studies have explored a range of factors governing the optimal use of caffeine (CAF) in athletes, limited research has explored how time of day (TOD) affects the ergogenic effects of various CAF dosages on physical performance. This study aimed to increase knowledge about how different recommended CAF doses (3 mg/kg vs. 6 mg/kg) ingested at different TODs affected maximal high-intensity physical performance and the perception of potential side effects in female athletes. In this double-blind, randomized, and counterbalanced study, 15 low CAF consumer athletes (aged 18.3 ± 0.5 y) underwent six trials, including three testing conditions assessed across two TODs: one in the morning (08:00 a.m.) and one in the evening (06:00 p.m.). During each condition, the participants ingested either a placebo, 3 mg/kg CAF (CAF (3 mg)), or 6 mg/kg CAF (CAF (6 mg)) capsules 60 min before each test with an in-between washout period of at least 72 h. In each trial, the participants performed a countermovement jumps test (CMJ), a modified agility t test (MATT), a repeated sprint ability (RSA), a rating of perceived exertion (RPE), and finally, a CAF side effects questionnaire. Our findings indicate the absence of an ergogenic effect on CMJ, MAT, and RSA performance in the evening after administering CAF (3 mg) or CAF (6 mg) compared to a placebo. Likewise, when CAF was ingested in the morning, there was an improvement in these performances with both CAF (3 mg) and CAF (6 mg), with greater improvement observed after CAF (6 mg). Additionally, neither the CAF dosage nor the TOD had a significant effect on the RPE. The occurrence of side effects increased significantly after the evening ingestion of CAF, particularly with a moderate dose of CAF (6 mg). Our findings indicate that the effectiveness of CAF depends on the TOD and CAF dosage. When ingested in the morning, a moderate dose of CAF (6 mg), rather than CAF (3 mg), is more effective in improving short-term physical performance without affecting CAF side effects in female athletes. Nevertheless, when ingested in the evening, neither dose was sufficient to enhance short-term physical performance, and both dosages increased the incidence of CAF side effects, particularly at a moderate dose.

Diet quality and anxiety: a critical overview with focus on the gut microbiome

Anxiety disorders disproportionally affect females and are frequently comorbid with eating disorders. With the emerging field of nutritional psychiatry, focus has been put on the impact of diet quality in anxiety pathophysiology and gut microbiome underlying mechanisms. While the relationship between diet and anxiety is bidirectional, improving dietary habits could better facilitate the actions of pharmacological and psychological therapies, or prevent their use. A better understanding of how gut bacteria mediate and moderate such relationship could further contribute to develop personalized programs and inform probiotics and prebiotics manufacturing. To date, studies that look simultaneously at diet, the gut microbiome, and anxiety are missing as only pairwise relationships among them have been investigated. Therefore, this study aims at summarizing and integrating the existing knowledge on the dietary effects on anxiety with focus on gut microbiome. Findings on the effects of diet on anxiety are critically summarized and reinterpreted in relation to findings on (i) the effects of diet on the gut microbiome composition, and (ii) the associations between the abundance of certain gut bacteria and anxiety. This novel interpretation suggests a theoretical model where the relationship between diet and anxiety is mediated and/or modulated by the gut microbiome through multiple mechanisms. In parallel, this study critically evaluates methodologies employed in the nutritional field to investigate the effects of diet on anxiety highlighting a lack of systematic operationalization and assessment strategies. Therefore, it ultimately proposes a novel evidence-based approach that can enhance studies validity, reliability, systematicity, and translation to clinical and community settings.

Acute low dose caffeine affects behavior profile and activity, an examination of male rats with high or low anxiety-like behavior

Anxiety disorders affect up to one third of the population. Caffeine, an adenosine receptor antagonist, is thought to have a dose-dependent effect on anxiety. We recently showed that a high dose of caffeine (50 mg/kg) differentially affected anxiety-like behavior in rats with high or low baseline anxiety-like behavior, replicating findings using relatively high doses in human patient samples. It is not known if low doses of caffeine have similar effects. The elevated plus maze (EPM) was used to categorize male Wistar rats (13 weeks of age) into groups of high or low anxiety-like behavior. Behavior was evaluated using the multivariate concentric square field (MCSF) test and the EPM after a low 10 mg/kg dose of caffeine. Multivariate data analysis demonstrated that caffeine decreased the differences between the high and low anxiety group, whereas the separation remained for the high and low control groups. For the caffeine treated rats, univariate statistics showed an increase in parameters regarding activity in the EPM and duration in the slope of the MCSF. Regarding risk-taking, shelter-seeking, and exploratory behavior, caffeine did not affect the groups differently. In conclusion, these results demonstrate increased activity in the caffeine-treated rats, together with a potentially anxiolytic effect and increased impulsivity that did not differ between the baseline anxiety groups. In contrast to high caffeine doses, a low dose does not generally affect rats with high anxiety at baseline differently than rats with low anxiety-like behavior. Further studies are warranted to fully elucidate the effects of caffeine in anxiety.

Caffeine intake is associated with less severe depressive symptoms in noncancer populations: an analysis based on NHANES 2007-2016

Depression and cancer are both prevalent diseases worldwide. Numerous cancer patients experience psychological illnesses, especially depression, following a malignancy's dismal prognosis. Although some research has suggested that caffeine may be protective against depressive symptoms, it is still unclear how caffeine and cancer patients are related. Thus, we hypothesized that moderate daily caffeine intake may reduce the risk of depression in both the cancer and noncancer populations. Data were extracted and combined from the National Health and Nutrition Examination Survey from 2007 to 2016. After controlling for potential confounding factors, interaction effects analysis was used to clarify the interaction between caffeine and cancer on depressive symptoms. Linear regression analysis and restricted cubic splines were used to further analyze the relationship between caffeine and depression in cancer and noncancer populations. A total of 24,145 participants were included in the analysis. In the noncancer population, the quartile 3 group of caffeine intake showed a negative association between caffeine intake and Patient Health Questionnaire-9 (PHQ-9) scores (β = -0.23, 95% confidence interval, -0.45 to -0.01; P = .041). No association between caffeine intake and PHQ-9 scores was observed in the cancer population. In both cancer and noncancer populations, restricted cubic splines indicated a nonlinear trend between caffeine and PHQ-9 scores, with the lowest PHQ-9 scores when caffeine intake was 119.52 mg. In the noncancer population, moderate daily caffeine intake (quartile 3 group; range, 119.5-236.5 mg) was associated with reduced depressive symptoms, whereas in the cancer population, no association was found between caffeine intake and depression.

Acute caffeine differently affects risk-taking and the expression of BDNF and of adenosine and opioid receptors in rats with high or low anxiety-like behavior

Anxiety disorders are common psychiatric conditions with a partially elucidated neurobiology. Caffeine, an unspecific adenosine receptor antagonist, is a common psychostimulant with anxiogenic effects in sensitive individuals. High doses of caffeine produce anxiety-like behavior in rats but it is not known if this is specific for rats with high baseline anxiety-like behavior. Thus, the aim of this study was to investigate general behavior, risk-taking, and anxiety-like behavior, as well as mRNA expression (adenosine A2A and A1, dopamine D2, and, μ, κ, δ opioid, receptors, BDNF, c-fos, IGF-1) in amygdala, caudate putamen, frontal cortex, hippocampus, hypothalamus, after an acute dose of caffeine. Untreated rats were screened using the elevated plus maze (EPM), giving each rat a score on anxiety-like behavior based on their time spent in the open arms, and categorized into a high or low anxiety-like behavior group accordingly. Three weeks after categorization, the rats were treated with 50 mg/kg caffeine and their behavior profile was studied in the multivariate concentric square field (MCSF) test, and one week later in the EPM. qPCR was performed on selected genes and corticosterone plasma levels were measured using ELISA. The results demonstrated that the high anxiety-like behavior rats treated with caffeine spent less time in risk areas of the MCSF and resituated towards the sheltered areas, a behavior accompanied by lower mRNA expression of adenosine A2A receptors in caudate putamen and increased BDNF expression in hippocampus. These results support the hypothesis that caffeine affects individuals differently depending on their baseline anxiety-like behavior, possibly involving adenosine receptors. This highlights the importance of adenosine receptors as a possible drug target for anxiety disorders, although further research is needed to fully elucidate the neurobiological mechanisms of caffeine on anxiety disorders.

Gender Differences in the Frequency of Positive and Negative Effects after Acute Caffeine Consumption

Gender-specific caffeine-related adverse effects should be thoroughly investigated. Sixty-five adult participants were included in the study, 30 men and 35 women (age, 22.5 ± 2.8; body weight, 71.7 ± 16.2 kg; BMI, 23.6 ± 4.4). The participants who were classified as low and moderate caffeine users received 3 mg/kg, and high caffeine users received 6 mg/kg of caffeine in one dose. One hour after ingestion of caffeine and within twenty-four hours, the participants completed a side effect questionnaire. Effects after the ingestion of CAF were divided into two subgroups: negative (muscle soreness, increased urine output, tachycardia and palpitations, anxiety or nervousness, headache, gastrointestinal problems, and insomnia) and positive (perception improvement; increased vigor/activeness). Caffeine ingestion resulted in a statistically significant association between gender and negative effects one hour after ingestion (p = 0.049). Gender and positive effects one hour after ingestion (p = 0.005), and between gender and positive effects within 24 h after ingestion (p = 0.047). There were significant associations between gender and perception improvement (p = 0.032) and gender and increased vigor/activeness (p = 0.009) one hour after ingestion. Nearly 30% of men and 54% of women reported negative effects. At the same time, 20% of women and more than 50% of men reported positive effects. Gender is an important factor in the negative and positive effects of caffeine consumption.

Dietary sources, health benefits, and risks of caffeine

Dietary intake of caffeine has significantly increased in recent years, and beneficial and harmful effects of caffeine have been extensively studied. This paper reviews antioxidant and anti-inflammatory activities of caffeine as well as its protective effects on cardiovascular diseases, obesity, diabetes mellitus, cancers, and neurodegenerative and liver diseases. In addition, we summarize the side effects of long-term or excessive caffeine consumption on sleep, migraine, intraocular pressure, pregnant women, children, and adolescents. The health benefits of caffeine depend on the amount of caffeine intake and the physical condition of consumers. Moderate intake of caffeine helps to prevent and modulate several diseases. However, the long-term or over-consumption of caffeine can lead to addiction, insomnia, migraine, and other side effects. In addition, children, adolescents, pregnant women, and people who are sensitive to caffeine should be recommended to restrict/reduce their intake to avoid potential adverse effects.