Coffee and caffeine consumption and depression: A meta-analysis of observational studies

Impact of Coffee Intake on Measures of Wellbeing in Mice

Coffee intake is increasingly recognized as a life-style factor associated with the preservation of health, but there is still a debate on the relative effects of caffeinated and decaffeinated coffee. We now tested how the regular drinking of caffeinated and decaffeinated coffee for 3 weeks impacted on the behavior of male and female adult mice. Males drinking caffeinated coffee displayed statistically significant lower weight gain, increased sensorimotor coordination, greater motivation in the splash test, more struggling in the forced swimming test, faster onset of nest building, more marble burying and greater sociability. Females drinking caffeinated coffee displayed statistically significant increased hierarchy fighting, greater self-care and motivation in the splash test and faster onset of nest building. A post-hoc two-way ANOVA revealed sex-differences in the effects of caffeinated coffee (p values for interaction between the effect of caffeinated coffee and sex) on the hierarchy in the tube test (p = 0.044; dominance), in the time socializing (p = 0.044) and in the latency to grooming (p = 0.048; selfcare), but not in the marble burying test (p = 0.089). Intake of decaffeinated coffee was devoid of effects in males and females. Since caffeine targets adenosine receptors, we verified that caffeinated but not decaffeinated coffee intake increased the density of adenosine A1 receptors (A1R) and increased A1R-mediated tonic inhibition of synaptic transmission in the dorsolateral striatum and ventral but not dorsal hippocampus, the effects being more evident in the ventral hippocampus of females and striatum of males. In contrast, caffeinated and decaffeinated coffee both ameliorated the antioxidant status in the frontal cortex. It is concluded that caffeinated coffee increases A1R-mediated inhibition in mood-related areas bolstering wellbeing of both males and females, with increased sociability in males and hierarchy struggling and self-care in females.

Coffee and stress management: How does coffee affect the stress response?

This chapter explores the complex relationship between coffee drinking and stress management, highlighting the advantages and disadvantages of this widely consumed beverage. The chapter explores the physiological, psychological, and social effects of coffee on stress response and resilience through a thorough analysis of recent studies. It highlights the negative consequences of excessive intake on cardiovascular, gastrointestinal, and mental health while also discussing how moderate coffee consumption may lower stress levels, improve coping skills, and promote relaxation. Considerations for vulnerable populations, interactions with medications and supplements, and sustainability concerns in coffee production and consumption are also addressed. By identifying missing gaps in our understanding of coffee and stress management, the chapter underscores the need for future research to elucidate underlying mechanisms and promote mindful consumption practices. Ultimately, by embracing a holistic approach that considers individual health, environmental sustainability, and social responsibility, we can harness the potential of coffee to support resilience, well-being, and sustainability for individuals and communities worldwide.

The effect of coffee consumption on three main bone disorders: a Mendelian randomization trial

INTRODUCTION

Despite a large number of observational studies examining the effect of coffee consumption(CC) on bone disorders(BDs), particularly, osteoarthritis(OA), osteoportic fracture(OF), and rheumatoid arthritis(RA), the conclusions are highly controversial. Thus, it is essential to examine the causal association between CC and BDs.

MATERIALS AND METHODS

Mendelian randomization (MR) analysis was performed to assess the causal influence of CC on OF, RA, and OA. The main endpoint was the odds ratio (OR) of the inverse variance weighted (IVW) approach. In addition, the weighted median (WM), MR-Egger regressions, MR-pleiotropy residual sum and outlier (MR-PRESSO) and multivariable MR (MVMR) were included in sensitivity analyses. Furthermore, the function of causal SNPs was evaluated by gene ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein-protein interaction networks.

RESULTS

Primary MR analysis based on the IVW method suggested that changes in CC alter risk of OF (OR = 1.383, 95%CI 1.079-1.853, P = 0.039), RA(OR: 1.623, 95%CI 1.042-2.527, P = 0.032) and HOA (hip osteoarthritis, OR = 1.536, 95% CI 1.044-2.259, P = 0.021). However, these causal relationships were not robust in sensitivity analyses. In contrast, there is a positive causal relationship between increased CC and the risk of KOA (knee osteoarthritis, OR: 2.094, 95%CI: 1.592-2.754, P = 1.41 × 10-7), as evidenced by the IVW using random effect. A similar effect size was observed across all MR sensitivity analyses, with no evidence of horizontal pleiotropy.

CONCLUSION

Based on our MR analysis, increased CC was causally linked to an increase in the risk of KOA. Genetic predictions suggested that CC reduction may have benefits for bone health.

Coffee and mental disorders: How caffeine affects anxiety and depression

Caffeine, the main psychoactive component in coffee, has garnered significant attention for its potential impact on the most prevalent mental health conditions like anxiety and depression. This chapter comprehensively examines the neurobiological effects of caffeine, its influence on anxiety and depression, and relevant clinical studies. Caffeine exerts its psychostimulant effects primarily through antagonizing adenosine receptors, modulating neurotransmitter systems, and influencing intracellular calcium signaling in the brain. Caffeine exhibits dose-dependent effects. While moderate caffeine consumption is safe in healthy adults and may offer benefits for mental health, excessive intake is linked to adverse effects on neurological and psychiatric health and can aggravate symptoms, highlighting the importance of adjusting consumption patterns. High caffeine intake correlates with elevated anxiety levels, especially in individuals predisposed to anxiety disorders. However, the relationship between caffeine consumption and the risk of depression is intricate, with some studies suggesting a potential protective effect of moderate intake, while others find no significant association. Individual variations in caffeine metabolism, sensitivity, and genetic factors considerably impact responses to caffeine. The chapter also explores the therapeutic potential of caffeine as an adjunct treatment and outlines challenges and future research directions in elucidating caffeine's multifaceted role in mental health.

Prediction of Positive Patient Health Questionnaire-2 Screening Using Area Deprivation Index in Primary Care

Depression is recognized as a significant public health issue in the United States. The National Survey on Drug Use and Health reports that 21.0 million adults aged 18 or older had major depressive disorder in 2020, including 14.8 million experiencing a major depressive episode with severe impairment. The aim is to predict the positivity of Patient Health Questionnaire-2 (PHQ-2) outcomes among patients in primary care settings by analyzing a range of variables, including socioeconomic status, demographic characteristics, and health behaviors, thereby identifying those at increased risk for depression. Employing a machine learning approach, the study utilizes retrospective data from electronic health records across 15 primary care clinics in South Florida to explore the relationship between social determinants of health (SDoH), including area of deprivation index (ADI) and PHQ-2 positivity. The study encompasses 15 primary care clinics located in South Florida, where a diverse patient population receives care. Analysis included 94,572 patient visits; 74,636 records were included in the study. If a zip+4 was not available or an ADI score did not exist, the visit was not included in the final analysis. Screening involved the PHQ-2, assessing depressed mood and anhedonia, with a cutoff >2 indicating positive screening. ADI was used to assess SDoH by matching patients' residential postal codes to ADI national percentiles. Demographics, sexual history, tobacco use, caffeine intake, and community involvement were also evaluated in the study. Over 40 machine learning algorithms were explored for their accuracy in predicting PHQ-2 outcomes, using software tools including Scikit-learn and stats models in Python. Variables were normalized, scored, and then subjected to predictive regression models, with Random Forest showing outstanding performance. Feature engineering and correlation analysis identified ADI, age, education, visit type, coffee intake, and marital status as significant predictors of PHQ-2 positivity. The area under the curve and model accuracies varied across clinics, with specific clinics showing higher predictive accuracy and others (p > .05). The study concludes that the ADI, as a proxy for SDoH, alongside other individual factors, can predict PHQ-2 positivity. Health organizations can use this information to anticipate health needs and resource allocation.

Association of sugary drinks, carbonated beverages, vegetable and fruit juices, sweetened and black coffee, and green tea with subsequent depression: A five-year cohort study

BACKGROUND & AIMS

Evidence on the impact of beverage consumption on depression is limited in the Asian population. Specifically, there is little information available on vegetable and fruit juices, while whole vegetables and fruits are reportedly protective against depression. Furthermore, evidence is scarce in differentiating the impacts of sweetened and black coffee. We aimed to examine the association of the consumption of total sugary drinks, carbonated beverages, vegetable and fruit juices, sweetened and black coffee, and green tea with subsequent depression in a general population sample.

METHODS

We studied individuals without a history of cancer, myocardial infarction, stroke, diabetes, or depression at baseline in 2011-2016, with a five-year follow-up. We used Poisson regression models and the g-formula, thereby calculating the risk difference (RD) for depression. Multiple sensitivity analyses were conducted. Missing data were handled using random forest imputation. We also examined effect heterogeneity based on sex, age, and body mass index by analyzing the relative excess risk due to interaction and the ratio of risk ratios.

RESULTS

In total, 94,873 individuals were evaluated, and 80,497 completed the five-year follow-up survey for depression. Of these, 18,172 showed depression. When comparing the high consumption group with the no consumption group, the fully adjusted RD (95% CI) was 3.6% (2.8% to 4.3%) for total sugary drinks, 3.5% (2.1% to 4.7%) for carbonated beverages, 2.3% (1.3% to 3.4%) for vegetable juice, 2.4% (1.1% to 3.6%) for 100% fruit juice, and 2.6% (1.9% to 3.5%) for sweetened coffee. In contrast, the fully adjusted RD (95% CI) was -1.7% (-2.6% to -0.7%) for black coffee. The fully adjusted RD for green tea did not reach statistical significance. The results were robust in multiple sensitivity analyses. We did not find substantial effect heterogeneity based on sex, age, and body mass index.

CONCLUSIONS

Total sugary drinks, carbonated beverages, vegetable and fruit juices, and sweetened coffee may increase the risk of depression, whereas black coffee may decrease it.

Beverages - a scoping review for Nordic Nutrition Recommendations 2023

Background: Coffee, tea, sugar-sweetened beverages (SSBs), and low- and no-calorie sweetened beverages (LNCSBs) are generally frequently consumed in the Nordic and Baltic countries. These beverages have also been related to potential health effects. This scoping review describes the evidence for the role of coffee, tea, SSBs, and LNCSBs for health-related outcomes as a basis for setting and updating food-based dietary guidelines. We used evidence from several qualified systematic reviews (i.e. World Cancer Research Fund, US Dietary Guidelines Advisory Committee, European Food Safety Authority, and World Health Organization) and performed a search for additional systematic reviews. The evidence suggests that moderate coffee and tea consumption do not have long-term adverse health effects. The long-term favorable effects of coffee consumption are related to reduced risk of endometrial and liver cancer, type 2 diabetes, and cardiovascular deaths. However, results from randomized controlled trials (RCTs) suggest that coffee brews that are rich in diterpenes, such as boiled coffee, increase serum cholesterol concentrations. High caffeine intake in pregnancy is associated with higher risk of pregnancy loss, preterm birth, and low birth weight. High consumption of SSBs has been associated with increased risk of obesity, type 2 diabetes, hypertension, and cardiovascular disease, based on data from RCTs and prospective cohort studies. The consumption of LNCSBs may result in a small reduction in body weight in adults, likely mediated through the effect of reduced energy intake, but has neutral effects on other cardiometabolic risk markers using evidence from RCTs. However, evidence from observational studies indicates increased risk of cardiometabolic diseases among high LNCSB consumers. In conclusion, current evidence suggests that moderate coffee and tea consumption have no long-term adverse health effects. The evidence of beneficial effects of coffee consumption on liver and endometrial cancer risk, and some cardiovascular outcomes, comes from observational studies. High consumption of boiled coffee should be avoided due to negative effect on lipid profile. Pregnant women should not exceed the recommended daily dose of caffeine intake of 200 mg set by the European Food Safety Authority as a safe level for the fetus. High consumption of SSBs has consistently been associated with adverse health effects, which is mainly due to excess energy intake, and should be limited. The conflicting results from RCTs and observational studies regarding LNCSBs may be due to revere causation and should be explored further.

Coffee consumption and migraine: a population-based study

Although coffee is one of the most consumed caffeinated beverages worldwide, the role of coffee consumption in migraine is controversial. This study examined the relationship between coffee consumption and clinical characteristics in participants with migraine compared to those with non-migraine headache. This cross-sectional study used data from a nationwide survey on headache and sleep. Coffee consumption was classified as no-to-low (< 1 cup/day), moderate (1-2 cups/day), or high (≥ 3 cups/day). Of the 3030 survey participants, 170 (5.6%) and 1,768 (58.3%) were identified as having migraine and non-migraine headache, respectively. Coffee consumption tended to increase in the order of non-headache, non-migraine headache, and migraine (linear-by-linear association, p = 0.011). Although psychiatric comorbidities (depression for migraine and anxiety for non-migraine headache) and stress significantly differed according to coffee consumption, most headache characteristics and accompanying symptoms did not differ among the three groups for participants with migraine and non-migraine headache. Response to acute headache treatment-adjusted for age, sex, depression, anxiety, stress, preventive medication use, and current smoking-was not significantly different by coffee consumption in participants with migraine and non-migraine headache. In conclusion, most headache-related characteristics and acute treatment response did not significantly differ by coffee consumption in migraine and non-migraine headache.

Dietary flavonoid intake is associated with a lower risk of depressive symptoms in US adults: Data from NHANES 2007-2008, 2009-2010, and 2017-2018

BACKGROUND

Depressive symptoms is an important public health problem. The aim of the present study is to examine the association of dietary flavonoid intake with risk of depressive symptoms.

METHODS

In this study, we conducted an assessment to investigate the potential association between dietary flavonoid intake and the risk of depressive symptoms. Our analysis was based on a nationally representative sample of 9674 adults who participated in the 2007-2010 and 2017-2018 National Health and Nutrition Examination Surveys. Flavonoid intake was measured using a 24-hour dietary recall method, while depressive symptoms was evaluated using the Patient Health Questionnaire-9. To examine the relationship between dietary flavonoid intake and the risk of depressive symptoms, we employed logistic regression, subgroup and restricted cubic spline models.

RESULTS

Following multivariate adjustment, the study found a negative association between total flavonoids, anthocyanidins, flavanones, flavones, isoflavones and the risk of depressive symptoms. In subgroup analysis, total flavonoid intake was inversely associated with risk of depressive symptoms among women whereas no association was found among man. Additionally, a non-linear relationship was observed between total flavonoid intake and depressive symptoms, with statistical significance (P for nonlinearity <0.001).

LIMITATIONS

The present study employed a cross-sectional design, which precludes the establishment of causality. Furthermore, the data relied on self-reported measures.

CONCLUSIONS

In present study, moderate total flavonoids intake, but not high intake, was associated with lower odds of depressive symptoms suggesting a U-shaped association.

Variables Affecting the Extraction of Antioxidants in Cold and Hot Brew Coffee: A Review

Coffee beans are a readily available, abundant source of antioxidants used worldwide. With the increasing interest in and consumption of coffee beverages globally, research into the production, preparation, and chemical profile of coffee has also increased in recent years. A wide range of variables such as roasting temperature, coffee grind size, brewing temperature, and brewing duration can have a significant impact on the extractable antioxidant content of coffee products. While there is no single standard method for measuring all of the antioxidants found in coffee, multiple methods which introduce the coffee product to a target molecule or reagent can be used to deduce the overall radical scavenging capacity. In this article, we profile the effect that many of these variables have on the quantifiable concentration of antioxidants found in both cold and hot brew coffee samples. Most protocols for cold brew coffee involve an immersion or steeping method where the coffee grounds are in contact with water at or below room temperature for several hours. Generally, a higher brewing temperature or longer brewing time yielded greater antioxidant activity. Most studies also found that a lower degree of coffee bean roast yielded greater antioxidant activity.

Relationship between Baseline Physical Activity and Generalized Anxiety Disorder and Major Depressive Disorder Treatment Outcomes

OBJECTIVES

Generalized anxiety disorder and major depressive disorder often benefit from medication and psychotherapy. Our aim was to determine whether a correlation exists between patient baseline physical activity and response to treatment.

METHODS

This was a retrospective study that included adult patients with anxiety and depression who received outpatient care for their conditions by providers in the Department of Psychiatry and Psychology of the Mayo Clinic in Jacksonville, Florida. Statistical analyses were used to analyze whether Rapid Assessment of Physical Activity scores as a measure of baseline exercise correlated to changes in Patient Health Questionnaire-9 (PHQ-9) scores or Generalized Anxiety Disorder-7-item scale (GAD-7) scores during treatment for anxiety or depression. Factors including age, sex, smoking status, and caffeine intake also were analyzed.

RESULTS

When comparing change in GAD-7 or PHQ-9 scores from baseline to follow-up during treatment for anxiety or depression, there was no significant difference based on Rapid Assessment of Physical Activity scores. Caffeine intake had a direct correlation with PHQ-9 scores from baseline to 12 to 24 weeks but no correlation with GAD-7 scores.

CONCLUSIONS

Overall, the amount of physical activity a patient participates in before anxiety or depression treatment does not appear to affect improvement outcomes. Caffeine intake may improve depression severity scores; however, further research is needed to assess whether this could be a part of future treatment plans.

Higher caffeine consumption is associated with insufficient sleep time in Brazilian adults (CUME study)

We aimed to evaluate the association between caffeine intake and sleep time in Brazilian adults. This cross-sectional study was conducted with 6,356 participants from the Cohort of Universities of Minas Gerais (CUME Study). Data was collected through an online self-report questionnaire. Of the total, 31.9% of the participants had insufficient sleep. Women were found to sleep less than men (64.1 vs. 35.9%; p < 0.001), as well as being more likely to consume higher doses of caffeine (55.2%, p < 0.001). Coffee (35.7%), dark chocolate (25.2%), milk chocolate (15.2%), and diet soda (11.0%) were the foods that more contributed to caffeine intake. Individuals in the highest quartile of caffeine intake (87.0 - 572.0 mg/day) had a 19% higher prevalence of insufficient sleep compared with the lowest quartile (PR: 1.19; 95%CI: 1.08 - 1.31). Future studies are needed to investigate the genetic and hormonal factors involved in the interindividual response in this population.

Caffeine Consumption and Depression, Anxiety, and Stress Levels Among University Students in Medina: A Cross-Sectional Study

Introduction Caffeine is a psychoactive stimulant frequently found in coffee, tea, energy drinks, and some medications. Various mental health challenges, including stress, anxiety, and depression, commonly affect college students. Moreover, an individual's mental and physical health can be significantly impacted by stress, anxiety, and depression. However, the impact of caffeine on mental health, particularly its association with depressive and anxiety symptoms, remains inconclusive. Thus, this study aimed to evaluate the amount of caffeine consumed by university students and its association with depression, anxiety, and stress levels. Material and method This cross-sectional study was performed on Taibah University students in Medina from both health-related and non-health-related colleges. We used a self-administrated questionnaire composed of four sections: the informed consent section; sociodemographic information; the Depression, Anxiety, and Stress Scale (DASS-21), which assessed the depression, anxiety, and stress levels; and a caffeine-measuring questionnaire, which reported daily caffeine intake in milligrams per day. Result This cross-sectional study examined a 520 convenience sample of Taibah University students with an age range from 17 to 29 years. The majority of the participants were single (95.2%), most of them were female (73.8%), and slightly more than half (51.5%) were recruited from health-related colleges. According to the study's DASS-21 score results, 45.8% of the students had extremely severe stress, 61% had extremely severe anxiety, and 51% had extremely severe depression. The most frequently reported sources of daily caffeine among the participants were Arabic coffee (69.6%), specialty coffee (57.5%), black tea (56.3%), cola (48.7%), and regular coffee (48.5%). The overall daily amount of consumed caffeine ranged from zero to 4276.7 mg/oz. However, no significant association was found between the severity of the DASS-21 score and the daily consumption of caffeine among Taibah University students. Conclusion Our study shows no significant association between the severity of depression, anxiety, and stress and daily caffeine consumption among university students. This proves the opposite of the theory that high levels of caffeine consumption can be correlated to high levels of depression, stress, and anxiety.

Effects of coffee intake on airway hypersensitivity and immunomodulation: an in vivo murine study

BACKGROUND/OBJECTIVES

Coffee is a complex chemical mixture, with caffeine being the most well-known bioactive substance. The immunomodulatory and anti-inflammatory properties of coffee and caffeine impact health in various aspects, including the respiratory system. The objective is to investigate the effects of coffee and caffeine on airway hyperresponsiveness and allergic reactions, as well as to analyze and compare associated cytokine profiles.

MATERIALS/METHODS

BALB/c mice were intraperitoneally sensitized with ovalbumin (OVA) and given OVA inhalation to induce airway hypersensitivity. Two weeks after sensitization, they were intragastrically gavaged with coffee or caffeine, both containing 0.3125 mg caffeine, daily for 4 weeks. Control mice were fed with double-distilled water. Serum OVA-specific antibody levels were measured beforehand and 5 weeks after the first gavage. Airway hyperresponsiveness was detected by whole body plethysmography after gavage. Cytokine levels of bronchoalveolar lavage and cultured splenocytes were analyzed.

RESULTS

Coffee effectively suppressed T helper 2-mediated specific antibody response. Airway responsiveness was reduced in mice treated with either coffee or caffeine. Compared to the control, coffee significantly reduced OVA-specific immunoglobulin (Ig) G, IgG1 and IgE antibody responses (P < 0.05). Caffeine also attenuated specific IgG and IgG1 levels, though IgE level was unaffected. Coffee significantly reduced interleukin (IL)-4 and increased IL-10 concentration in spleen cells and bronchoalveolar lavage fluid (P < 0.05).

CONCLUSIONS

Coffee effectively attenuated airway hyperresponsiveness and systemic allergic responses induced by OVA food allergen in mice. As a complex composition of bioactive substances, coffee displayed enhanced immunomodulatory and anti-inflammatory effects than caffeine.

The association between coffee consumption and risk of incident depression and anxiety: Exploring the benefits of moderate intake

Accumulating evidence has reported the associations of coffee consumption with physical conditions and mortality, but the associations with mental disorders were limited. The objective of this study was to examine the associations of coffee consumption with incident depression and anxiety, and to assess whether the associations differed by coffee subtypes (instant, ground, and decaffeinated coffee) or additives (milk, sugar-sweetened, and artificial-sweetened). In this prospective cohort study, we utilized data from the UK Biobank and included a total of 146,566 participants who completed the touchscreen questionnaire at baseline between 2006 and 2010. During the follow-up, incident depression and anxiety were measured in 2016 using the Patient Health Questionnaire (PHQ)-9 and the Generalised Anxiety Disorder Assessment (GAD)-7, respectively. Multivariable-adjusted logistic regression models and restricted cubic splines were used to assess the associations. Approximately 80.7% of participants reported consuming coffee, and most drank 2 to 3 cups per day (41.2%). We found J-shaped associations between coffee consumption and both incident depression and anxiety, with the lowest risk of the mental disorders occurring at around 2-3 cups per day. Results were similar for participants who drank 2-3 cups of ground coffee, milk-coffee, or unsweetened coffee. Our findings highlight that 2-3 cups of coffee consumption could be recommended as part of a healthy lifestyle to improve mental health.

Diet and depression: A systematic review of whole dietary interventions as treatment in patients with depression

BACKGROUND & RATIONALE

Depression is a common mental illness that afflicts over 300 million individuals worldwide. Despite a variety of therapeutic options available, a significant number of depressed patients fail to respond to treatment. Current guidelines for treating depression suggest that supplementation of essential nutrients may be an appropriate adjunctive to treatment, but research investigating full dietary interventions for depressed patients is scarce.

STUDY OBJECTIVE

The primary aim of this study was to systematically review published scientific literature investigating full dietary interventions as treatment for individuals with a diagnosis of depression. In doing so, we assessed existing evidence for recommendation of a dietary intervention and reviewed theory of how diet may be important in this context.

METHODS

A systematic search was conducted using OVID to search Medline, PsychINFO, and EMBASE, and PubMed for relevant publications. Only studies including full dietary interventions for patients with Major Depressive Episode, Major Depressive Disorder, Persistent Depressive Disorder, Seasonal Affective Disorder, or Dysthymia, as diagnosed using criteria defined in the chapter of "Depressive Disorders" in the DSM, were included.

RESULTS

Only five studies met the inclusion criteria for this review. All five studies included in this review reported improvements in mood following dietary intervention as compared to the comparison group. However, heterogeneity in both the dietary intervention and the outcome(s) measured made it difficult to compare these studies against each other and to generalize them to larger populations.

CONCLUSION

The findings of this review provide preliminary evidence for the positive impact of dietary interventions in the treatment of depressed patients. However, the mechanism by which particular diets induce positive changes in mood, be it through anti-inflammatory mechanisms or via weight loss in overweight patients, is unclear. Future research investigating the impact of dietary interventions on a large-scale is warranted and needed.

Association of Caffeine Consumption and Brain Amyloid Positivity in Cognitively Normal Older Adults

BACKGROUND

Several epidemiological studies have reported the protective role of caffeine on health outcomes; however, it remained debatable on caffeine consumption and brain amyloid positivity.

OBJECTIVE

We aimed to determine the relationship between caffeine consumption and brain amyloid pathology in cognitively normal older adults.

METHODS

The dataset used for analysis in this cross-sectional study was selected from the Anti-Amyloid Treatment in Asymptomatic Alzheimer's (A4) Study. Multivariable logistic regression analyses were performed to explore the association between caffeine consumption and amyloid positivity using odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

In total, 4,394 participants were included in the final analysis. No significant association between caffeine consumption and amyloid positivity was observed in the whole participants (OR, 0.95; 95% CI, 0.78-1.14; p = 0.558). Subgroup analysis showed that caffeine intake was significantly associated with decreased amyloid positivity in males (OR, 0.72; 95% CI, 0.54-0.97; p = 0.032) but not in females (OR, 1.14; 95% CI, 0.90-1.46; p = 0.280), and the association between caffeine and amyloid positivity was not affected by age or APOE genotypes. In addition, different levels of caffeine were not associated with amyloid positivity.

CONCLUSION

The findings suggest that caffeine consumption was not significantly associated with amyloid positivity in the whole sample. However, caffeine consumption may be inversely associated with amyloid positivity among males but not females. More studies are needed to explore the mechanisms underlying caffeine consumption and brain amyloid positivity.

Purinergic signaling in cognitive impairment and neuropsychiatric symptoms of Alzheimer's disease

About 10 million new cases of dementia develop worldwide each year, of which up to 70% are attributable to Alzheimer's disease (AD). In addition to the widely known symptoms of memory loss and cognitive impairment, AD patients frequently develop non-cognitive symptoms, referred to as behavioral and psychological symptoms of dementia (BPSDs). Sleep disorders are often associated with AD, but mood alterations, notably depression and apathy, comprise the most frequent class of BPSDs. BPSDs negatively affect the lives of AD patients and their caregivers, and have a significant impact on public health systems and the economy. Because treatments currently available for AD are not disease-modifying and mainly aim to ameliorate some of the cognitive symptoms, elucidating the mechanisms underlying mood alterations and other BPSDs in AD may reveal novel avenues for progress in AD therapy. Purinergic signaling is implicated in the pathophysiology of several central nervous system (CNS) disorders, such as AD, depression and sleep disorders. Here, we review recent findings indicating that purinergic receptors, mainly the A₁, A_2A, and P2X7 subtypes, are associated with the development/progression of AD. Current evidence suggests that targeting purinergic signaling may represent a promising therapeutic approach in AD and related conditions. This article is part of the Special Issue on "Purinergic Signaling: 50 years".

Predictors of treatment-response to caffeine combination products, acetaminophen, acetylsalicylic acid (aspirin), and nonsteroidal anti-inflammatory drugs in acute treatment of episodic migraine

OBJECTIVE

To identify predictors of acute treatment optimization for migraine with "over-the-counter" (OTC) or prescription nonsteroidal anti-inflammatory drugs (NSAIDs) as well as other widely used OTCs including acetaminophen, caffeine combination products (CCP), and acetylsalicylic acid (ASA, aspirin) among people with episodic migraine and to develop models that predict treatment response to each class of OTCs.

BACKGROUND

Efficacy of acute OTC medications for migraine varies greatly. Identifying predictors of treatment response to particular classes of medication is a step toward evidence-based personalized therapy.

METHODS

For this prediction model development study, we used data from 2224 participants from the American Migraine Prevalence and Prevention (AMPP) study who were aged ≥18 years, met criteria for migraine, had <15 monthly headache days, and reported being on monotherapy for acute migraine attacks with one of the following classes medications: CCP (N = 711), acetaminophen (N = 643), ASA (N = 110), and prescription or OTC NSAIDs (N = 760). The primary outcome measures of treatment optimization were adequate 2-h pain freedom (2hPF) and adequate 24-h pain relief (24hPR), which were defined by responses of half the time or more to the relevant items on the Migraine Treatment Optimization Questionnaire-6.

RESULTS

The mean (SD) age of the participants was 46.2 (13.1) years, 79.4% (1765/2224) were female, 43.7% (972/2224) reported adequate 2hPF, and 46.1% (1025/2224) reported adequate 24hPR. Those taking CCP had better 2hPF and 24PR outcomes. For those taking NSAIDs, better outcomes were associated with lower average pain intensity (2hPF: odds ratio [OR] 0.89, 95% confidence interval [CI] 0.80-0.99; 24PR: OR 0.86, 95% CI 0.77-0.96), cutaneous allodynia (2hPF: OR 0.92, 95% CI 0.89-0.96; 24PR: OR 0.91, 95% CI 0.87-0.95), depressive symptoms (2hPF: OR 0.95, 95% CI 0.92-0.98; 24PR: OR 0.95, 95% CI 0.91-0.99), and Migraine Disability Assessment Scale (MIDAS) grade (2hPF: OR 0.76, 95% CI 0.64-0.90; 24PR: OR 0.79, 95% CI 0.65-0.95). Adequate 2hPF for those taking CCP was associated with male gender (OR 1.83, 95% CI 1.21-2.77), lower average pain intensity (OR 0.80, 95% CI 0.70-0.91), lower cutaneous allodynia (OR 0.94, 95% CI 0.90-0.97), and lower Migraine Symptom Severity Scale Score (MSSS; OR 0.91, 95% CI 0.86-0.97). Adequate 24hPR for those taking CCP was associated with lower average pain intensity (OR 0.85, 95% CI 0.75-0.96), lower cutaneous allodynia (OR 0.92, 95% CI 0.89-0.96), and lower MIDAS grade (OR 0.81, 95% CI 0.68-0.96). Participants who were married (OR 1.51, 95% CI 1.05-2.19), had lower average pain intensity (OR 0.79, 95% CI 0.70-0.89), lower MSSS (OR 0.93, 95% CI 0.88-0.99), less depression (OR 0.96, 95% CI 0.93-0.99), and lower MIDAS grade (OR 0.72, 95% CI 0.59-0.87) had adequate 2hPF after taking acetaminophen. Participants who were married (OR 1.50, 95% CI 1.02-2.21), had lower pain intensity (OR 0.78, 95% CI 0.69-0.88), less depression (OR 0.95, 95% CI 0.91-0.98) and lower MIDAS grade (OR 0.53, 95% CI 0.42-0.67) had higher 24hPR following use of acetaminophen. A lower MSSS was the only factor associated with higher 2hPF and 24PR after using ASA (OR 0.78, 95% CI 0.67-0.92 and OR 0.79, 95% CI 0.67-0.93). Predictive models had modest performance in identifying responders to each class of OTC.

CONCLUSION

A large subgroup of people with migraine had an inadequate response to their usual acute OTC migraine treatment 2- and 24-h after dosing. These findings suggest a need to improve OTC treatment for some and to offer prescription acute medications for others. Predictive models identified several factors associated with better treatment-response in each OTC class. Selecting OTC treatment based on factors predictive of treatment optimization might improve patient outcomes.

Protective role of antioxidant supplementation for depression and anxiety: A meta-analysis of randomized clinical trials

BACKGROUND

New research supports an integrated approach to treating depression, and lifestyle modifications should be a regular component of both preventative and treatment programs. Therefore, in order to investigate the relationship between various antioxidant supplements and depressive status, we carried out a meta-analysis of randomized controlled trials (RCT).

METHODS

We thoroughly searched PubMed, Medline, Scopus, and Web of Science databases to screen publications focusing on the effects of antioxidant supplements on depression status. The meta-analysis mainly compared depression scores between groups that received antioxidant supplements and controls. We also pooled studies reporting changes in anxiety status as a secondary outcome.

RESULTS

52 studies with 4049 participants were eventually identified. The meta-analysis found that the positive effect of antioxidant supplementation, such as magnesium (SMD = 0.16, p = 0.03), zinc (SMD = 0.59, p = 0.01), selenium (SMD = 0.33, p = 0.009), CoQ10 (SMD = 0.97, p = 0.05), tea and coffee (SMD = 1.15, p = 0.001) and crocin (MD = 6.04, p < 0.00001), on depressive status were all significant. And antioxidant supplementation also showed significant improvement in anxiety (SMD = 0.40, p < 0.00001). Subgroup analysis by scale types and countries were performed, and antioxidant supplementation's positive effects on depressive and anxiety states remained significant.

LIMITATIONS

This study did not limit the characteristics of the included population, and the diversity of scales also contributed to the heterogeneity.

CONCLUSION

Intake of antioxidant supplements is associated with improved depression and anxiety states, further affirms the therapeutic potential of antioxidant supplements as adjunctive therapy to conventional antidepressants.

NMDA Receptor Activation and Ca2+/PKC Signaling in Nicotine-Induced GABA Transport Shift in Embryonic Chick Retina

Nicotinic receptors are present in the retina of different vertebrates, and in the chick retina, it is present during early development throughout to post-hatching. These receptors are activated by nicotine, an alkaloid with addictive and neurotransmitter release modulation properties, such as GABA signaling. Here we evaluated the mechanisms of nicotine signaling in the avian retina during the development of neuron-glia cells at a stage where synapses are peaking. Nicotine almost halved [³H]-GABA uptake, reducing it by 45% whilst increasing more than two-fold [³H]-GABA release in E12 embryonic chick retinas. Additionally, nicotine mediated a 33% increase in [³H]-D-aspartate release. MK-801 50 μM blocked 66% of nicotine-induced [³H]-GABA release and Gö 6983 100 nM prevented the nicotine-induced reduction in [³H]-GABA uptake by rescuing 40% of this neurotransmitter uptake, implicating NMDAR and PKC (respectively) in the nicotinic responses. In addition, NO-711 prevented [³H]-GABA uptake and release induced by nicotine. Furthermore, the relevance of calcium influx for PKC activation was evidenced through fura-2 imaging. We conclude that the shift of GABA transport mediated by nicotine promotes GABA release by inducing transporter reversal via nicotine-induced EAA release through EAATs, or by a direct effect of nicotine in activating nicotinic receptors permeable to calcium and promoting PKC pathway activation and shifting GAT-1 activity, both prompting calcium influx, and activation of the PKC pathway and shifting GAT-1 activity.

Association between dietary caffeine, coffee, and tea consumption and depressive symptoms in adults: A systematic review and dose-response meta-analysis of observational studies

Background

Recent studies have reported an association between dietary caffeine intake (coffee and tea) and the presence of depressive symptoms. However, the findings are not conclusive.

Purpose

This study aimed to examine the correlation between the consumption of dietary caffeine (coffee and tea) and the presence of depressive symptoms in adults.

Methods

PubMed and Scopus databases were searched until December 2021. Two investigators analyzed data from identified studies and rated the quality of the evidence using the GRADE approach. Using the random-effects models, we estimated the relative risks (RRs) and 95% confidence intervals (CIs). We also modeled the dose-response associations through a one-stage, weighted mixed-effects meta-analysis.

Results

A total of 29 eligible studies included a total of 422,586 participants. On comparing the highest with the lowest category in cohort studies, we identified an inverse association between the intake of coffee and depressive symptoms (RR: 0.89, 95%CI: 0.82-0.95; I2 = 63.7%, GRADE = low). There was a 4% reduction in the risk of depression associated with an increase in coffee intake of 240 ml/day (RR: 0.96, 95%CI: 0.95, 0.98; I2 = 22.7%). By comparing the highest category with the lowest category in cohort studies, we discovered that caffeine intake was inversely associated with depressive symptoms (RR: 0.86, 95%CI: 0.79, 0.93; I2 = 0.0%, GRADE = moderate). Based on our data analysis, no correlation exists between tea consumption and depressive symptoms.

Conclusion

According to our findings, coffee and dietary caffeine may have a protective effect against the development of depression. However, no evidence suggesting a link between tea consumption and reduced depressive symptoms has been found. Therefore, further longitudinal studies are needed to substantiate the causal relationship between coffee, tea, and caffeine and the risk of depression.

Identifying transdiagnostically relevant risk and protective factors for internalizing psychopathology: An umbrella review of longitudinal meta-analyses

Internalizing mental disorders are highly comorbid with one another, and evidence suggests that etiological processes contributing to these disorders often overlap. This systematic umbrella review aimed to synthesize meta-analytic evidence from observational longitudinal studies to provide a comprehensive overview of potentially modifiable risk and protective factors across the depressive, anxiety, and eating disorder psychopathology domains. Six databases were searched from inception to August 2022. Only meta-analyses of longitudinal studies that accounted for baseline psychopathology (either via exclusion of baseline cases or statistical adjustment for baseline symptoms) were included. Methodological quality of meta-analyses was evaluated using the AMSTAR 2, and quality of evidence for each analysis was rated using GRADE. Study selection, quality assessment, and data extraction were conducted in duplicate by independent reviewers. The protocol for this review was registered with PROSPERO (CRD42020185575). Sixty-one meta-analyses were included, corresponding to 137 meta-analytic estimates for unique risk/protective factor-psychopathology relationships. Most potential risk/protective factors, however, were examined only in relation to depressive psychopathology. Concern over mistakes and self-esteem were the only risk and protective factors, respectively, identified as statistically significant across depressive, anxiety, and eating disorder psychopathology domains. Eight risk factors and four protective factors also emerged as having transdiagnostic relevance across depressive and anxiety domains. Results suggest intervention targets that may be valuable for preventing/treating the spectrum of internalizing psychopathology and reducing comorbidity. However, few factors were identified as transdiagnostically relevant across all three internalizing domains, highlighting the need for more research investigating similar sets of potential risk/protective factors across internalizing domains.

Dietary diversity, physical activity and depressive symptoms among middle-aged women: A cross-sectional study of 48,637 women in China

OBJECTIVE

Depression is the leading cause of mental health-related disease burden. This study aimed to investigate the relationship among dietary diversity, physical activity and depressive symptoms in middle-aged women.

METHOD

Based on the WHO guidelines on physical activity, subjects who meet moderate-intensity aerobic physical exercise of 150-300 min per week were qualified or otherwise unqualified. The dietary diversity scores (DDS) were developed according to the balanced diet pagoda and assessed the consumption of nine food groups. The total scores ranged from 0 to 9 and could divide into three levels: insufficient [DDS-1] (score of 1-5), moderate [DDS-2] (score of 6-7), and sufficient [DDS-3] (score of 8-9).

RESULTS

An age at menarche ≥12 years old (OR = 0.94; 95 % CI: 0.89-1.00; p < 0.05), a higher dietary diversity score [DDS-3] (OR = 0.59; 95 % CI: 0.55-0.63; p < 0.001), drinking coffee (OR = 0.88; 95 % CI: 0.84-0.92; p < 0.001), and qualified physical activity (OR = 0.69; 95 % CI: 0.66-0.72; p < 0.001) were protective factors for depressive symptoms, while an age at first birth ≤20 years old (OR = 1.23; 95 % CI: 1.12-1.36; p < 0.001) or ≥30 years old (OR = 1.18; 95 % CI: 1.11-1.26; p < 0.001), eating late-night snacks (OR = 1.44; 95 % CI: 1.36-1.52; p < 0.001), drinking sugar-sweetened beverages (OR = 1.15; 95 % CI: 1.06-1.24; p < 0.001), and overeating (OR = 2.30; 95 % CI: 2.069-2.56; p < 0.001) were risk factors.

CONCLUSION

This study suggested that dietary diversity and physical activity are associated with depressive symptoms in middle-aged women. To improve dietary diversity, attention should be given to dietary patterns and dietary habits, instead of simply increasing the amount of food.

Coffee consumption, health benefits and side effects: a narrative review and update for dietitians and nutritionists

Coffee is one of the most popular beverages worldwide; however, its impact on health outcomes and adverse effects is not fully understood. The current review aims to establish an update about the benefits of coffee consumption on health outcomes highlighting its side effects, and finally coming up with an attempt to provide some recommendations on its doses. A literature review using the PubMed/Medline database was carried out and the data were summarized by applying a narrative approach using the available evidence based on the literature. The main findings were the following: first, coffee may contribute to the prevention of inflammatory and oxidative stress-related diseases, such as obesity, metabolic syndrome and type 2 diabetes; second, coffee consumption seems to be associated with a lower incidence of several types of cancer and with a reduction in the risk of all-cause mortality; finally, the consumption of up to 400 mg/day (1-4 cups per day) of caffeine is safe. However, the time gap between coffee consumption and some drugs should be taken into account in order to avoid interaction. However, most of the data were based on cross-sectional or/and observational studies highlighting an association of coffee intake and health outcomes; thus, randomized controlled studies are needed in order to identify a causality link.

Coffee and caffeine intake and depression in postpartum women: A cross-sectional study from the National Health and Nutrition Examination Survey 2007-2018

This cross-sectional study examines the association between coffee and caffeine consumption and depressive symptoms in postpartum women. In total, 821 postpartum women who met the study's inclusion criteria were interviewed. Data were extracted from the 2007-2018 National Health and Nutrition Examination Survey. Coffee consumption and 11 confounding variables were considered and analyzed as baseline data. Weighted logistic regression models were constructed by adjusting the variables, and the odds ratios of total coffee, caffeinated coffee, and decaffeinated coffee were assessed for their impact on depression status. In addition, subgroup analyses were conducted according to race, breastfeeding status, and postpartum period. The results show that generic coffee and caffeinated coffee intake have a potentially protective effect in postpartum women. Drinking more than three cups of caffeinated coffee may lower the risk of postpartum depression, particularly in the 1-2 year postpartum period and in non-breastfeeding women. The association between decaffeinated coffee consumption and postpartum depression remains unclear.

Associations of dietary Provitamin A carotenoid intake with depressive symptoms in midlife women: Results from the study of Women's Health Across the Nation

BACKGROUND

To study the association of Provitamin A (pro-A) carotenoid intake from diet with depressive symptoms in midlife women.

METHODS

Data for this cross-sectional study were retrieved from baseline assessment of the Study of Women's Health Across the Nation (SWAN). Logistic regression and restricted cubic spline models were performed to examine the association pro-A carotenoid intake with depressive symptoms.

RESULTS

A total of 3054 midlife women aged 42-52 years were included in the present study. In overall midlife women, pro-A carotenoid intake was inversely associated with depressive symptoms (CES-D score ≥16). In premenopausal women, pro-A carotenoid intake was inversely associated with depressive symptoms after adjustment for age, race/ethnicity, total family income, education, physical activity, BMI, use of antidepressant, dietary total caloric, protein, carbohydrate, fat, vitamin C, vitamin E and pro-A carotenes in model 1. In fully adjusted model, after additional adjustment for day of cycle, FSH and SHBG, this association remained statistically significant. The fully adjusted odds ratios (ORs) with 95 % CI of depressive symptoms were 0.685 (0.450-1.043) in quartile 4 compared with quartile 1 for pro-A carotenoid intake. However, in early perimenopausal women, no statistically significant difference was observed between pro-A carotenoid intake and depressive symptoms after adjustment for confounders.

LIMITATIONS

This was a cross-sectional study, limiting causal inferences. Assessment of CES-D was based on a self-report scale.

CONCLUSION

Pro-A carotenoid intake may be inversely associated with depression symptoms in premenopausal women, but not in early perimenopausal women.

The Role of the Adenosine System on Emotional and Cognitive Disturbances Induced by Ethanol Binge Drinking in the Immature Brain and the Beneficial Effects of Caffeine

Binge drinking intake is the most common pattern of ethanol consumption by adolescents, which elicits emotional disturbances, mainly anxiety and depressive symptoms, as well as cognitive alterations. Ethanol exposure may act on the adenosine neuromodulation system by increasing adenosine levels, consequently increasing the activation of adenosine receptors in the brain. The adenosine modulation system is involved in the control of mood and memory behavior. However, there is a gap in the knowledge about the exact mechanisms related to ethanol exposure’s hazardous effects on the immature brain (i.e., during adolescence) and the role of the adenosine system thereupon. The present review attempts to provide a comprehensive picture of the role of the adenosinergic system on emotional and cognitive disturbances induced by ethanol during adolescence, exploring the potential benefits of caffeine administration in view of its action as a non-selective antagonist of adenosine receptors.

Biological Role of Nutrients, Food and Dietary Patterns in the Prevention and Clinical Management of Major Depressive Disorder

Major Depressive Disorder (MDD) is a growing disabling condition affecting around 280 million people worldwide. This complex entity is the result of the interplay between biological, psychological, and sociocultural factors, and compelling evidence suggests that MDD can be considered a disease that occurs as a consequence of an evolutionary mismatch and unhealthy lifestyle habits. In this context, diet is one of the core pillars of health, influencing multiple biological processes in the brain and the entire body. It seems that there is a bidirectional relationship between MDD and malnutrition, and depressed individuals often lack certain critical nutrients along with an aberrant dietary pattern. Thus, dietary interventions are one of the most promising tools to explore in the field of MDD, as there are a specific group of nutrients (i.e., omega 3, vitamins, polyphenols, and caffeine), foods (fish, nuts, seeds fruits, vegetables, coffee/tea, and fermented products) or dietary supplements (such as S-adenosylmethionine, acetyl carnitine, creatine, amino acids, etc.), which are being currently studied. Likewise, the entire nutritional context and the dietary pattern seem to be another potential area of study, and some strategies such as the Mediterranean diet have demonstrated some relevant benefits in patients with MDD; although, further efforts are still needed. In the present work, we will explore the state-of-the-art diet in the prevention and clinical support of MDD, focusing on the biological properties of its main nutrients, foods, and dietary patterns and their possible implications for these patients.

Behavioral, genetic and biochemical changes in the brain of the offspring of female mice treated with caffeine during pregnancy and lactation

The intrauterine environment is a critical location for exposure to exogenous and endogenous factors that trigger metabolic changes through fetal programming. Among the external factors, chemical compounds stand out, which include caffeine, since its consumption is common among women, including during pregnancy. Thereby, the aim of the present study was to evaluate the behavioral, genetic, and biochemical parameters in the offspring of female mice treated with caffeine during pregnancy and lactation. Swiss female mice (60 days old) received tap water or caffeine at 0.3 or 1.0 mg/mL during copulation (7 days), pregnancy (21 days) and lactation (21 days). After the end of the lactation period, the offspring were divided into groups (water, caffeine 0.3 or 1.0 mg/mL) with 20 animals (10 animals aged 30 days and 10 animals aged 60 days per group per sex). Initially, the offspring were submitted to behavioral tasks and then euthanized for genetic and biochemical analysis in the brain (cortex, striatum, and hippocampus). Behavioral changes in memory, depression, and anxiety were observed in the offspring: 30-day-old female offspring at 1.0 mg /mL dose presented anxiogenic behavior and male offspring the 0.3 mg/mL dose at 30 days of age did not alter long-term memory. Furthermore, an increase in DNA damage and oxidative stress in the brain were observed in the offspring of both sexes. Furthermore, there were changes in Ape-1, BAX, and Bcl-2 in the female offspring hippocampus at 30 days of life. Thus, with this study, we can suggest genotoxicity, oxidative stress, and behavioral changes caused by caffeine during pregnancy and lactation in the offspring that were not treated directly, but received through their mothers; thus, it is important to raise awareness regarding caffeine consumption among pregnant and lactating females.

Prediction of depression symptoms in individual subjects with face and eye movement tracking

BACKGROUND

Depression is a challenge to diagnose reliably and the current gold standard for trials of DSM-5 has been in agreement between two or more medical specialists. Research studies aiming to objectively predict depression have typically used brain scanning. Less expensive methods from cognitive neuroscience may allow quicker and more reliable diagnoses, and contribute to reducing the costs of managing the condition. In the current study we aimed to develop a novel inexpensive system for detecting elevated symptoms of depression based on tracking face and eye movements during the performance of cognitive tasks.

METHODS

In total, 75 participants performed two novel cognitive tasks with verbal affective distraction elements while their face and eye movements were recorded using inexpensive cameras. Data from 48 participants (mean age 25.5 years, standard deviation of 6.1 years, 25 with elevated symptoms of depression) passed quality control and were included in a case-control classification analysis with machine learning.

RESULTS

Classification accuracy using cross-validation (within-study replication) reached 79% (sensitivity 76%, specificity 82%), when face and eye movement measures were combined. Symptomatic participants were characterised by less intense mouth and eyelid movements during different stages of the two tasks, and by differences in frequencies and durations of fixations on affectively salient distraction words.

CONCLUSIONS

Elevated symptoms of depression can be detected with face and eye movement tracking during the cognitive performance, with a close to clinically-relevant accuracy (~80%). Future studies should validate these results in larger samples and in clinical populations.

Divergent Effects of the Nonselective Adenosine Receptor Antagonist Caffeine in Pre-Manifest and Motor-Manifest Huntington's Disease

There is a controversy about potentially positive or negative effects of caffeine consumption on onset and disease progression of neurodegenerative diseases such as Huntington’s Disease (HD). On the molecular level, the psychoactive drug caffeine targets in particular adenosine receptors (AR) as a nonselective antagonist. The aim of this study was to evaluate clinical effects of caffeine consumption in patients suffering from premanifest and motor-manifest HD. Data of the global observational study ENROLL-HD were used, in order to analyze the course of HD regarding symptoms onset, motor, functional, cognitive and psychiatric parameters, using cross-sectional and longitudinal data of up to three years. We split premanifest and manifest participants into two subgroups: consumers of >3 cups of caffeine (coffee, cola or black tea) per day (>375 mL) vs. subjects without caffeine consumption. Data were analyzed using ANCOVA-analyses for cross-sectional and repeated measures analysis of variance for longitudinal parameters in IBM SPSS Statistics V.28. Within n = 21,045 participants, we identified n = 1901 premanifest and n = 4072 manifest HD patients consuming >3 cups of caffeine/day vs. n = 841 premanifest and n = 2243 manifest subjects without consumption. Manifest HD patients consuming >3 cups exhibited a significantly better performance in a series of neuropsychological tests. They also showed at the median a later onset of symptoms (all p < 0.001), and, during follow-up, less motor, functional and cognitive impairments in the majority of tests (all p < 0.050). In contrast, there were no beneficial caffeine-related effects on neuropsychological performance in premanifest HD mutation carriers. They showed even worse cognitive performances in stroop color naming (SCNT) and stroop color reading (SWRT) tests (all p < 0.050) and revealed more anxiety, depression and irritability subscores in comparison to premanifest participants without caffeine consumption. Similarly, higher self-reported anxiety and irritability were observed in genotype negative/control group high dose caffeine drinkers, associated with a slightly better performance in some cognitive tasks (all p < 0.050). The analysis of the impact of caffeine consumption in the largest real-world cohort of HD mutation carriers revealed beneficial effects on neuropsychological performance as well as manifestation and course of disease in manifest HD patients while premanifest HD mutation carrier showed no neuropsychological improvements, but worse cognitive performances in some tasks and exhibited more severe signs of psychiatric impairment. Our data point to state-related psychomotor-stimulant effects of caffeine in HD that might be related to regulatory effects at cerebral adenosine receptors. Further studies are required to validate findings, exclude potential other unknown biasing factors such as physical activity, pharmacological interventions, gender differences or chronic habitual influences and test for dosage related effects.

Adenosine, caffeine, and sleep-wake regulation: state of the science and perspectives

For hundreds of years, mankind has been influencing its sleep and waking state through the adenosinergic system. For ~100 years now, systematic research has been performed, first started by testing the effects of different dosages of caffeine on sleep and waking behaviour. About 70 years ago, adenosine itself entered the picture as a possible ligand of the receptors where caffeine hooks on as an antagonist to reduce sleepiness. Since the scientific demonstration that this is indeed the case, progress has been fast. Today, adenosine is widely accepted as an endogenous sleep‐regulatory substance. In this review, we discuss the current state of the science in model organisms and humans on the working mechanisms of adenosine and caffeine on sleep. We critically investigate the evidence for a direct involvement in sleep homeostatic mechanisms and whether the effects of caffeine on sleep differ between acute intake and chronic consumption. In addition, we review the more recent evidence that adenosine levels may also influence the functioning of the circadian clock and address the question of whether sleep homeostasis and the circadian clock may interact through adenosinergic signalling. In the final section, we discuss the perspectives of possible clinical applications of the accumulated knowledge over the last century that may improve sleep‐related disorders. We conclude our review by highlighting some open questions that need to be answered, to better understand how adenosine and caffeine exactly regulate and influence sleep.

Empirically derived dietary patterns and their association with mental health: a cross-sectional sample of Iranian migraine patients (2019–2020)

Objectives

Based on a comprehensive search, we realized that there is no previous study conducted among migraine patients to assess the association between major dietary patterns and mental health. Therefore, the present study aims to explore the relationship between empirically-derived dietary patterns and depression, anxiety, and stress in a sample of Iranian migraine patients.

Methods

A total of 262 migraine patients (20–50 years) were selected through simple random sampling method for this study. Dietary intake during the previous year was determined using a validated 168-item, semi-quantitative food frequency questionnaire (FFQ), and major dietary patterns were derived using principal component analysis (PCA). For mental health evaluation, authors used the Depression, Anxiety, and Stress Scales (DASS- 21) questionnaire. Statistical analysis included multinomial logistic regression analysis and results were expressed as odds ratio (OR) with a 95% confidence interval (CI).

Results

We identified three major dietary patterns including “traditional”, “western”, and “healthy”. After controlling for potential confounders, those in the highest tertile of the healthy dietary pattern had lower odds of depression (OR = 0.44, 95% CI: 0.22, 0.88; P for trend: 0.030) and stress (OR = 0.50, 95% CI: 0.25, 0.99; P for trend: 0.049). However, no significant association was observed between western and traditional dietary patterns and mental disorders.

Conclusions

In summary, significant associations were documented between healthy dietary patterns and risk of depression and stress. Current findings urge migraine patients to increase their intakes of fruits, vegetables, eggs, whole grains, nuts and seeds, meat, and poultry and reduce the intake of fast foods and snacks, processed meat, fish, cola drink, condiments, dairy, and vegetable pickles to diminish the chance of depression and stress.

The Impact of Caffeine Intake on Mental Health Symptoms in Postmenopausal Females with Overactive Bladder Symptoms: A Randomized, Double-Blind, Placebo-Controlled Trial

Background: Caffeine has been associated with a dose-dependent variety of mental health changes, which have been found to precede or be a complication of overactive bladder (OAB) symptoms after menopause. The current study examines the effects of low and moderate caffeine intake on anxiety, depression, sleep, and stress in postmenopausal females with OAB. Materials and Methods: Eighty-one females were randomized in a prospective, double-blind, placebo-controlled study. Participants were allocated to 200 mg/day caffeine, 400 mg/day caffeine, and placebo capsules for 1 week each in a crossover design and evaluated using validated mental health questionnaires. Symptoms during each treatment phase were measured using Beck Anxiety and Depression Inventory, Insomnia Severity Index, and Perceived Stress Scale. Linear regression models were used to examine the impact of low (200 mg/day) and moderate (400 mg/day) dose of caffeine and placebo on mental health. Results: Fifty-six female participants finished the study. The mean age was 69.2 years (58.0-84.0 years). Two females dropped out during the treatment phase with 400 mg/day caffeine intake due to side effects associated with headaches and nausea. Moderate dose of caffeine showed a small positive effect on mental health, specifically a decrease in anxiety during 7 days of exposure (p < 0.05). Conclusions: Moderate caffeine use may decrease anxiety in postmenopausal patients with underlying OAB, whereas depression, insomnia, and perceived stress were not affected by low-to-moderate caffeine intake. Our results support that counseling efforts on moderate caffeine consumption in postmenopausal patients underline that low-to moderate caffeine intake may be appropriate and possibly beneficial unless contraindicated due to other underlying conditions. Clinical Trials Registration: clinicaltrials.gov (NCT02180048).

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

(1) Background: Caffeine is one of the most consumed psychoactive stimulants worldwide. It has been suggested that caffeine intake at large doses can induce anxiety, whereas evidence of the role of low to moderate caffeine intake is scarce and inconsistent. Therefore, we aimed to assess the association between caffeine intake and general anxiety in adults recruited from the general population. (2) Methods: Participants from the French NutriNet-Santé web cohort with data on caffeine intake and general anxiety (assessed during 2013−2016 through the trait subscale of Spielberger’s State-Trait Anxiety Inventory Form Y; STAI-T, sex-specific top quartile = high trait anxiety) were included in this cross-sectional analysis (n = 24,197; 74.1% women; mean age = 53.7 ± 13.9 years). Mean dietary intake was estimated using ≥2 self-reported 24-h dietary records. Sex-specific tertiles of caffeine intake and low/high trait anxiety were calculated. Multivariable logistic regression models were fitted to assess the odds ratio (OR) and 95% confidence interval (CI) for the association between caffeine intake and general anxiety by sex. (3) Results: In the total sample, the mean caffeine intake (mg/day) from all dietary sources combined was 220.6 ± 165.0 (women = 212.4 ± 159.6; men = 243.8 ± 177.7, p < 0.01). Women in the highest tertile of caffeine intake showed significantly higher odds for high trait anxiety compared to those in the lowest tertile (reference), even after adjustment for potential confounders (OR: 1.13; 95% CI: 1.03−1.23). No significant associations were detected among men. Sensitivity analyses according to perceived stress level and sugar intake, respectively, showed similar results. (4) Conclusions: The results suggest that higher caffeine intake is associated with higher odds of general anxiety among women but not among men. Further research is needed to confirm the sex-specific findings and elucidate the potential causal relationship between caffeine intake and anxiety status.

Relationships between urinary antimony concentrations and depressive symptoms in adults

BACKGROUND

Antimony is widely used in industrial production. The general population may be exposed to long-term low-dose antimony, and there are no studies on antimony and depression symptoms. This study aims to explore the relationships between urinary antimony concentrations and depressive symptoms in adults.

METHODS

We conducted a cross-sectional study using data from U.S. National Health and Nutrition Examination Survey (NHANES) 2007-2016 for urinary antimony (N = 8538). Depressive symptoms were assessed through Patient's Health Questionnaire (PHQ-9). In order to determine the relationships between urinary antimony concentrations and depressive symptoms, binary logistic regression model and restricted cubic spline were used. Dominance analysis was used to explore the relative importance between variables associated with depressive symptoms.

RESULTS

There was a significant positive relationship between urinary antimony concentrations and depressive symptoms in the general population, and OR with 95% CI was 1.72 (1.15, 2.60). This relationship also occurred in participants without disease status, and OR with 95% CI was 2.05 (1.10, 3.82). After stratified gender, the urinary antimony concentrations were positively correlated with depressive symptoms in the highest tertiles of female participants, and OR with 95% CI was 1.74 (1.06, 2.86). After adjusted urinary lead, arsenic, cadmium, and mercury as covariates, the result was still statistically significant, and OR with 95% CI was 1.83 (1.23, 2.72). Restricted cubic spline showed a nonlinear positive relationship between urinary antimony and depressive symptoms. Based on the result of dominance analysis, the relative importance of urinary antimony concentration accounted for 3.58%.

CONCLUSION

This study indicated that urinary antimony was positively related to depressive symptoms, especially in female.

Coffee and caffeine intake in relation to symptoms of psychological disorders among adults

OBJECTIVE

Given that there is an inconsistency in the findings related to the relationship between coffee and caffeine consumption and symptoms of psychological disorders, we performed a cross-sectional analysis to examine the association between coffee and caffeine intake and symptoms of psychological disorders among adults.

DESIGN

In this cross-sectional study, 3362 participants were included. We assessed the coffee and caffeine intakes using a self-completed food frequency questionnaire (FFQ). Symptoms of depression, anxiety, and psychological distress were assessed using HADS and GHQ screening tools.

RESULTS

The mean age of participants in this study was 36.2±7.8 years. After controlling for potential confounders, individuals who consumed coffee weekly or more had a significantly lower odds of symptoms of depression (OR: 0.67; 95% CI: 0.46-0.96) and symptoms of anxiety (OR: 0.57; 95% CI: 0.34-0.95) compared with those who did not consume coffee. However, no significant association was found between coffee intake and symptoms of psychological distress (OR: 0.98; 95%CI: 0.68-1.42). No significant relationship was found between caffeine intake and odds of symptoms of depression (OR: 0.94; 95% CI: 0.75-1.16), symptoms of anxiety (OR: 0.90; 95% CI: 0.67-1.20), and symptoms of psychological distress (OR: 1.13; 95% CI: 0.89-1.42).

CONCLUSION

Compared with lack of coffee intake, weekly or more coffee consumption might be correlated with symptoms of depression and anxiety.

Caffeine is negatively associated with depression in patients aged 20 and older

INTRODUCTION

Previous studies have observed the association between caffeine intake and depression, but few have considered the potential threshold effect of this issue. Therefore, the study aimed to examine the association between caffeine consumption and depression in patients aged 20 years or older using curve fitting analysis.

METHODS

The population was 3,263 patients from the 2017 to 2018 National Health and Nutrition Examination Survey (NHANES) with reliable answers to questions of caffeine intake and depression. Participants' depression levels were assessed using the 9-item Patient Health Questionnaire (PHQ-9) depression scale and the caffeine consumption were investigated in a private room of NHANES. The confounding variables of this study included level of education, monthly sleepiness, age, marital status, race, cigarette smoking, sex and recreational activities.

RESULTS

In linear regression analysis, patients with a higher PHQ-9 score tend to have less caffeine intake. A similar conclusion was drawn in logistic regression model using PHQ-9 ≥ 10 as a cut-off score for depression. But when caffeine intake exceeded 90 mg, there was no significant association between caffeine intake and depression based on the curve fitting analysis.

DISCUSSION

These results suggest that people can consume some caffeine to reduce depression. But further study is needed to examine the precise causal relationship between these factors.

A Brewed Awakening: Neuropsychiatric Effects of Caffeine in Older Adults

This article provides a current review of the literature examining caffeine use in older adults. Caffeine use is prevalent among older adults; thus, providers need to be aware of the prevalence and diagnostic criteria of caffeine use disorder versus nonproblematic use. The relationship between caffeine and various neuropsychiatric disorders, including Parkinson's disease, Alzheimer's disease, insomnia, and late-life depression, is reviewed. The neurobiological effects of caffeine are described, along with clinically relevant interactions between caffeine and common psychotropic medications.

Habitual coffee drinkers display a distinct pattern of brain functional connectivity

Coffee is the most widely consumed source of caffeine worldwide, partly due to the psychoactive effects of this methylxanthine. Interestingly, the effects of its chronic consumption on the brain's intrinsic functional networks are still largely unknown. This study provides the first extended characterization of the effects of chronic coffee consumption on human brain networks. Subjects were recruited and divided into two groups: habitual coffee drinkers (CD) and non-coffee drinkers (NCD). Resting-state functional magnetic resonance imaging (fMRI) was acquired in these volunteers who were also assessed regarding stress, anxiety, and depression scores. In the neuroimaging evaluation, the CD group showed decreased functional connectivity in the somatosensory and limbic networks during resting state as assessed with independent component analysis. The CD group also showed decreased functional connectivity in a network comprising subcortical and posterior brain regions associated with somatosensory, motor, and emotional processing as assessed with network-based statistics; moreover, CD displayed longer lifetime of a functional network involving subcortical regions, the visual network and the cerebellum. Importantly, all these differences were dependent on the frequency of caffeine consumption, and were reproduced after NCD drank coffee. CD showed higher stress levels than NCD, and although no other group effects were observed in this psychological assessment, increased frequency of caffeine consumption was also associated with increased anxiety in males. In conclusion, higher consumption of coffee and caffeinated products has an impact in brain functional connectivity at rest with implications in emotionality, alertness, and readiness to action.

Stress and its contribution to the development of depression symptoms are reduced in caregivers of elderly with higher educational level

Caregivers of elderly people with neurodegenerative diseases are highly vulnerable to stressful situations and mood disorders due to their work conditions. Stress has been associated with an increased risk of developing depression, and studies have supported that caffeine consumption can act as an independent protective factor for disorder. This study investigated indexes of stress and depression symptoms in caregivers of the elderly with neurodegenerative diseases, their caffeine intake and the association between stress and depressive symptoms with the salivary biomarkers cortisol, nitric oxide and DNA damage. Participants (n = 81) were recruited from the community between July 2018 and April 2019. Stress was assessed using Lipp's Inventory of Stress Symptoms, and depressive symptoms were measured using the Hamilton Depressive Rating Scale. Participants provided a 72-hour recall of their diet to measure caffeine intake. Saliva samples were used to measure cortisol and nitric oxide. DNA damage was measured through micronuclei frequency after swabbing on the buccal mucosa. The majority of caregivers displayed stress and depressive symptoms. Stress was associated with educational level, tobacco use and total DNA damage. The indexes found in this population were not associated with caffeine intake or other salivary biomarkers, indicating that only some salivary molecules could be used as biomarkers for stress-related disorders. Caregivers of the elderly are exposed to stressful situations daily, however, we observed that educational level can reduce the psychological symptoms of stress and thus reduce the negative impact on quality of life.

The relationship of caffeinated beverages with depressive symptoms and decision-making

BACKGROUND: Caffeine can affect depressive symptoms and decision-making. OBJECTIVE: This study aims to examine the relationship between caffeinated beverages consumption with depressive symptoms and decision-making styles. METHODS: This cross-sectional study was conducted with 432 adults working in office environment. The questionnaire consisting of individuals’ socio-demographic attributes, the frequency and the amount of caffeinated beverages consumption, the “Epidemiological Research Center-Depression (CES-D) Scale” and the “Decision-Making Styles Scale” were used. The frequency and amount of caffeinated beverages were determined using the food frequency questionnaire (FFQ). The participants were asked to choose which cup/mug they prefer to drink their caffeinated beverages and what amount they consume that beverage at a time. All the data were collected using online platforms. RESULTS: In the study, 76.7%of the participants were female and the mean age was 31.5±8.0 years. The average daily total caffeine intake of the participants was 425.8±461.4 mg and the total CES-D scale score was 17.7±11.2 points. It was found that as the amount of caffeine consumed increased, intuitive decision-making decreased and depressive symptoms increased (p <  0.05). In linear regression analysis, total caffeine consumption was found to be a significant predictor for the intuitive decision-making score (B: –0.151; p:0.002). When caffeine consumption is controlled, intuitive and rational decision making decreases with increasing depressive symptoms while addiction and avoidance decision making increased (p <  0.05). CONCLUSIONS: As a result, the amount of caffeine consumed daily was related to intuitive decision-making but did not effect depression. It has been observed that depressive symptoms affect decision-making styles in different ways. To our knowledge, our study is the first to examine the effects of caffeine consumption on depression and decision-making styles. Accordingly, future studies may focus on the link between caffeine consumption, depression, and decision-making styles in larger populations and the mechanisms that influence this relationship.

Role of dietary factors in the prevention and treatment for depression: an umbrella review of meta-analyses of prospective studies

The role of diet in depression is becoming increasingly acknowledged. This umbrella review aimed to summarize comprehensively the current evidence reporting the effects of dietary factors on the prevention and treatment of depression. PubMed, Embase, and the Cochrane Library were searched up to June 2021 to identify relevant meta-analyses of prospective studies. Twenty-eight meta-analyses, with 40 summary estimates on dietary patterns (n = 8), food and beverages (n = 19), and nutrients (n = 13) were eligible. The methodological quality of most meta-analyses was low (50.0%) or very low (25.0%). Quality of evidence was moderate for inverse associations for depression incidence with healthy diet [risk ratio (RR): 0.74, 95% confidential interval (CI), 0.48-0.99, I² = 89.8%], fish (RR: 0.88, 95% CI, 0.79-0.97, I²= 0.0%), coffee (RR: 0.89, 95% CI, 0.84-0.94, I²= 32.9%), dietary zinc (RR: 0.66, 95% CI 0.50-0.82, I²= 13.9%), light to moderate alcohol (<40 g/day, RR: 0.77, 95% CI, 0.74-0.83, I²= 20.5%), as well as for positive association with sugar-sweetened beverages (RR: 1.05, 95% CI, 1.01-1.09, I²= 0.0%). For depression treatment, moderate-quality evidence was identified for the effects of probiotic [standardized mean difference (SMD): -0.31, 95% CI, -0.56 to -0.07, I²= 48.2%], omega-3 polyunsaturated fatty acid (SMD: -0.28, 95% CI, -0.47 to -0.09, I² = 75.0%) and acetyl-L-carnitine (SMD: -1.10, 95% CI, -1.65 to -0.56, I² = 86.0%) supplementations. Overall, the associations between dietary factors and depression had been extensively evaluated, but none of them were rated as high quality of evidence, suggesting further studies are likely to change the summary estimates. Thus, more well-designed research investigating more detailed dietary factors in association with depression is warranted.

Coffee consumption and psychological wellbeing among Japanese auto factory workers

BACKGROUND:

Health habits are sometimes closely related to physical and mental health status.

OBJECTIVE:

The relationship between coffee consumption and psychological wellbeing was evaluated by considering confounding factors.

METHODS:

A total of 5,256 men, aged 35 to 60 years, from a workplace in Japan participated in this study conducted in 2018. Psychological wellbeing was evaluated using the General Health Questionnaire (GHQ) 12-item version and multivariate logistic regression analysis was used for the analysis.

RESULTS:

Positive GHQ12 score was significantly associated with average daily sleeping time < 4 h, lack of regular exercise and younger age. In contrast, there was no significant association between positive GHQ12 score and coffee consumption. Coffee consumption and smoking status was not significantly related to psychological wellbeing as measured using the GHQ questionnaire. In contrast, aging, regular exercise and sleeping time were related to psychological wellbeing.

CONCLUSION:

Coffee consumption was not significantly related to psychological wellbeing, and casual association might be confirmed by a prospective study.

Exploring the Role of Nutraceuticals in Major Depressive Disorder (MDD): Rationale, State of the Art and Future Prospects

Major depressive disorder (MDD) is a complex and common disorder, with many factors involved in its onset and development. The clinical management of this condition is frequently based on the use of some pharmacological antidepressant agents, together with psychotherapy and other alternatives in most severe cases. However, an important percentage of depressed patients fail to respond to the use of conventional therapies. This has created the urgency of finding novel approaches to help in the clinical management of those individuals. Nutraceuticals are natural compounds contained in food with proven benefits either in health promotion or disease prevention and therapy. A growing interest and economical sources are being placed in the development and understanding of multiple nutraceutical products. Here, we summarize some of the most relevant nutraceutical agents evaluated in preclinical and clinical models of depression. In addition, we will also explore less frequent but interest nutraceutical products which are starting to be tested, also evaluating future roads to cover in order to maximize the benefits of nutraceuticals in MDD.

Associations of dietary B vitamins intakes with depression in adults

Background: The impact of the dietary B vitamins intakes on the development of depression has been scarcely investigated. Thus, this study aimed to examine the associations of dietary B vitamins intakes with the risk of depression in American adults. Methods: The data we used in this study were from the National Health and Nutrition Examination Survey (NHANES) 2007-2014. We used the Logistic regression models to analyze the associations of the dietary intakes of B vitamins with the risk of depression. Results: 17,732 individuals (8,623 males and 9,109 females) were enrolled in the study and they were all 18 or older. Compared to the lowest quartile of dietary intake, the ORs (95%CIs) of the highest quartile were 0.64 (0.50-0.82), 0.78 (0.62-0.97), 0.60 (0.47-0.78), 0.65 (0.50-0.84), and 0.71 (0.54-0.95) for vitamin B1, vitamin B2, niacin, vitamin B6, and vitamin B12, respectively. Compared to the people whose dietary intakes below the RDA in the model 2, those with intake meeting the RDA of vitamin B1 (OR: 0.68; 95%CI: 0.56-0.84), niacin (OR: 0.65; 95%CI: 0.51-0.81), B6 (OR: 0.65; 95%CI: 0.52-0.81), or B12 (OR: 0.65; 95%CI: 0.48-0.88) had a lower risk of depression, severally. We also found a nonlinear negative association between dietary vitamin B1, vitamin B2, niacin, vitamin B6, and vitamin B12 intakes and the risk of depression in the dose-response analyses, severally. Conclusions: Our results suggested that dietary vitamin B1, vitamin B2, niacin, vitamin B6, and vitamin B12 intakes may be inversely associated with the risk of depression.

Associations Between Workplace Factors and Depression and Anxiety in Australian Heavy Vehicle Truck Drivers

INTRODUCTION

A number of health issues have been identified as prevalent within the Australian heavy vehicle driving population. Mental illnesses, such as depression and anxiety, are among those disorders that have been regularly reported, however, the contributing factors are yet to be elucidated.

METHODS

This study aimed to assess the associations between workplace factors such as years of employment, social interaction and shift length, with depressive and anxious symptomology in a cohort of 60 Australian heavy vehicle drivers.

RESULTS

Significant positive associations were identified between depression and alcohol use (P = 0.044), coffee consumption (P = 0.037), number of accidents during career (P = < 0.004), and number of hours driving per shift (P ≤ 0.001). Anxiety was found to be positively associated with a number of hours driving per week (P ≤ 0.001), and the number of accidents or near misses during a driving career (P = 0.039).

CONCLUSION

Several workplace factors were identified as being correlated to depression or anxiety within this cohort, suggesting potential changes to rostering systems and education regarding alcohol use may benefit the mental health of this driver population.

Effects of black tea consumption and caffeine intake on depression risk in black tea consumers

BACKGROUND

The aim of this study was to compare black tea consumption and caffeine intake with depression status.

SUBJECTS AND METHODS

This study was conducted on 491 adults (M:169, F:322). The average daily caffeine intake of individuals was calculated using the amounts of caffeinated beverages they consumed daily and the caffeine contents of these beverages. The participants' depression status was determined using the Beck Depression Inventory (BDI). All of the research data were evaluated using STATA.

RESULTS

According to BDI scores, 30.1% of participants had depression. Black tea was consumed by all of the participants and also had the highest consumption level of 620.1±90.4mL and the mean caffeine intake of the participants was 629.5±418.8 mg. Multivariate regression analyses showed that consuming more than 1 cup was protective against depression up to 4 cups. Moreover, a 450-600 mg caffeine intake also reduces the risk of depression than lower or higher intake levels.

CONCLUSION

Our study suggests that black tea consumption up to 4 cups and caffeine intake between 450-600 mg can help protect against depression. Further studies are needed to better understand the protective effects of black tea and caffeine on depression.