Consumption of coffee or tea and symptoms of anxiety

Coffee and brain health: An introductory overview

Introduction to the "Impact of Coffee on Brain Health" explores the multifaceted relationship between coffee consumption and brain function. The chapter begins by highlighting coffee's global popularity and cultural significance, setting the stage for an in-depth exploration of its effects on brain health. It describes the intricate components of coffee, including caffeine, antioxidants, and polyphenols, elucidating their physiological and medicinal roles in promoting cognitive function and neuroprotection. While moderate coffee consumption offers potential benefits such as enhanced cognitive performance and mood regulation, excessive intake can pose risks such as insomnia and medication interactions. Research studies provide robust evidence supporting coffee's neuroprotective effects, while practical implications offer recommendations for optimizing consumption and minimizing risks. By embracing a personalized approach to coffee consumption and staying informed about its potential impacts, individuals can harness its benefits for brain health and overall well-being.

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.

Dietary phytochemical index in relation to risk of glioma: a case-control study in Iranian adults

BACKGROUND & AIM

No study is available that explores the association of dietary phytochemical index (DPI) with glioma. The objective of the current study was to assess this association in Iranian adults.

METHODS

This hospital-based case-control study included 128 newly-diagnosed cases of glioma and 256 age- and sex-matched controls. Data collection on dietary intakes was done using a 123-item validated food frequency questionnaire. Calculation of DPI was done as (dietary energy derived from phytochemical-rich foods (kcal)/total daily energy intake (kcal)) × 100. Logistic regression models were used to examine the association between DPI and glioma.

RESULTS

Individuals in the top tertile of DPI were more likely to be older and female. Before taking potential confounders into account, subjects in the top tertile of DPI tended to have a 40% reduced chance of glioma than those in the bottom tertile (OR: 0.60; 95% CI: 0.35-1.02, P = 0.06). After controlling for age, sex, energy intake, several demographic variables and dietary intakes, the association between DPI and glioma became strengthened (OR: 0.43; 95% CI: 0.19-0.97, P = 0.04).

CONCLUSION

High intakes of phytochemical-rich foods were associated with a lower risk of glioma in adults. High consumption of phytochemical-rich foods might be recommended to prevent glioma. However, further studies with a prospective design are needed to confirm our findings.

Bioactive Constituents in Caffeinated and Decaffeinated Coffee and Their Effect on the Risk of Depression—A Comparative Constituent Analysis Study

Coffee, a popular beverage throughout the world, has been shown to have numerous beneficial health effects, including reducing the risk of developing depression. This effect has only been shown with the consumption of caffeinated coffee and not decaffeinated coffee or caffeine alone and one of many hypotheses attributes this to the loss of key constituents during the decaffeination process. The aim of this study was to investigate whether any of the key bioactive coffee constituents with known anti-oxidant and anti-inflammatory effects are lost during the decaffeination process. The analysis of nine caffeinated and nine decaffeinated samples of various brands and batches of commonly consumed coffee in Australia using HPLC analysis found that, with the exception of caffeine, there were no significant differences in the quantity of other key bioactive coffee constituents in caffeinated and decaffeinated coffee. These results suggest that there may be an alternative explanation for the observed inverse correlation between caffeinated coffee consumption and the risk of developing depression.

Nicotine dependence, use of illegal drugs and psychiatric morbidity

The purpose of this study was to examine the association of smoking and nicotine dependence with psychiatric morbidity, controlling for the potential confounding effect of smoking on the relationship between the use of other substances and psychiatric morbidity. A sample of 290 adults were interviewed at a primary health centre (patients, 58%; patients' relatives, 34%; staff, 8%) to inquire about their tobacco, caffeine, alcohol, and illegal drug consumption. Psychiatric morbidity, defined by a score >6 on the General Health Questionnaire (GHQ-28), showed a strong direct association with nicotine dependence. The use of illegal drugs, but not of alcohol, was also strongly associated with psychiatric morbidity, after controlling for smoking. Both smoking and high nicotine dependence were also associated with use of caffeine, alcohol, cannabis and cocaine. High nicotine dependence may be considered as an expression of individual psychopathologic vulnerability. Tobacco may have a central facilitating role in the use of caffeine, alcohol, and illegal drug.

Preference for caffeine appears earlier in non-anxious than in anxious mice

Caffeine has reinforcing and anxiogenic properties. We have investigated whether the anxiety level of mice may influence their caffeine consumption. In a population of CD1 mice, animals were selected as anxious and non-anxious, using the elevated plus maze and the light/dark box tests. After a period during which we made mice able to associate the central effect of caffeine with the pipette delivering this substance, animals had free access to solvent (solution of sodium benzoate) and one of caffeine (0.3g/l) dissolved in this solvent. A progressive preference for the caffeine solution developed in both groups, but this occurred later in anxious than in non-anxious mice. Thus, it appears that the preference for caffeine is delayed in the anxious animals.

Blood pressure response to caffeine shows incomplete tolerance after short-term regular consumption

Caffeine acutely raises blood pressure (BP). The clinical significance of this effect depends on whether BP responses persist in persons who consume caffeine on a daily basis. Accordingly, the ability of caffeine to raise BP after 5 days of regular daily intake was tested in a randomized controlled trial. Individual differences in tolerance formation were then examined. Men (n=49) and women (n=48) completed a double-blind, crossover trial conducted over 4 weeks. During each week, subjects abstained for 5 days from dietary caffeine and instead used capsules totaling 0 mg, 300 mg, and 600 mg of caffeine per day in 3 divided doses. On day 6, in the laboratory, they used capsules with either 0 mg or 250 mg of caffeine at 9:00 am and 1:00 pm. Systolic/diastolic BP increases as a result of 250 mg of caffeine remained significant (P<0.006/0.001) at all levels of previous daily consumption. Individual difference comparisons found that although half the subjects had complete loss of systolic and diastolic BP responses to the challenge doses, the other half showed no loss in BP response, even after using 600 mg of caffeine per day for the previous 5 days (F >7.90, P <0.001). The sexes did not differ in degree of tolerance formation. Daily caffeine consumption failed to eliminate the BP response to repeated challenge doses of caffeine in half of the healthy adults who were tested. Caffeine may therefore cause persistent BP effects in persons who are regular consumers, even when daily intake is at moderately high levels.

Effects of caffeine on human behavior

The literature suggests that the following effects on behavior of adult humans may occur when individuals consume moderate amounts of caffeine. (1) Caffeine increases alertness and reduces fatigue. This may be especially important in low arousal situations (e.g. working at night). (2) Caffeine improves performance on vigilance tasks and simple tasks that require sustained response. Again, these effects are often clearest when alertness is reduced, although there is evidence that benefits may still occur when the person is unimpaired. (3) Effects on more complex tasks are difficult to assess and probably involve interactions between the caffeine and other variables which increase alertness (e.g. personality and time of day). (4) In contrast to the effects of caffeine consumption, withdrawal of caffeine has few effects on performance. There is often an increase in negative mood following withdrawal of caffeine, but such effects may largely reflect the expectancies of the volunteers and the failure to conduct "blind" studies. (5) Regular caffeine usage appears to be beneficial, with higher users having better mental functioning. (6) Most people are very good at controlling their caffeine consumption to maximise the above positive effects. For example, the pattern of consumption over the day shows that caffeine is often consumed to increase alertness. Indeed, many people do not consume much caffeine later in the day since it is important not to be alert when one goes to sleep. In contrast to effects found from normal caffeine intake, there are reports that have demonstrated negative effects when very large amounts are given or sensitive groups (e.g. patients with anxiety disorders) were studied. In this context caffeine has been shown to increase anxiety and impair sleep. There is also some evidence that fine motor control may be impaired as a function of the increase in anxiety. Overall, the global picture that emerges depends on whether one focuses on effects that are likely to be present when caffeine is consumed in moderation by the majority of the population or on the effects found in extreme conditions. The evidence clearly shows that levels of caffeine consumed by most people have largely positive effects on behavior. Excessive consumption can lead to problems, especially in sensitive individuals.

Caffeine and the central nervous system: mechanisms of action, biochemical, metabolic and psychostimulant effects

Caffeine is the most widely consumed central-nervous-system stimulant. Three main mechanisms of action of caffeine on the central nervous system have been described. Mobilization of intracellular calcium and inhibition of specific phosphodiesterases only occur at high non-physiological concentrations of caffeine. The only likely mechanism of action of the methylxanthine is the antagonism at the level of adenosine receptors. Caffeine increases energy metabolism throughout the brain but decreases at the same time cerebral blood flow, inducing a relative brain hypoperfusion. Caffeine activates noradrenaline neurons and seems to affect the local release of dopamine. Many of the alerting effects of caffeine may be related to the action of the methylxanthine on serotonin neurons. The methylxanthine induces dose-response increases in locomotor activity in animals. Its psychostimulant action on man is, however, often subtle and not very easy to detect. The effects of caffeine on learning, memory, performance and coordination are rather related to the methylxanthine action on arousal, vigilance and fatigue. Caffeine exerts obvious effects on anxiety and sleep which vary according to individual sensitivity to the methylxanthine. However, children in general do not appear more sensitive to methylxanthine effects than adults. The central nervous system does not seem to develop a great tolerance to the effects of caffeine although dependence and withdrawal symptoms are reported.

Epidemiologic studies utilizing surveys: accounting for the sampling design

BACKGROUND

Since large-scale health surveys usually have complicated sampling schemes, there is often a question as to whether the sampling design must be considered in the analysis of the data. A recent disagreement concerning the analysis of a body iron stores-cancer association found in the first National Health and Nutrition Examination Survey and its follow-up is used to highlight the issues.

METHODS

We explain and illustrate the importance of two aspects of the sampling design: clustering and weighting of observations. The body iron stores-cancer data are reanalyzed by utilizing or ignoring various aspects of the sampling design. Simple formulas are given to describe how using the sampling design of a survey in the analysis will affect the conclusions of that analysis.

RESULTS

The different analyses of the body iron stores-cancer data lead to very different conclusions. Application of the simple formulas suggests that utilization of the sample clustering in the analysis is appropriate, but that a standard utilization of the sample weights leads to an uninformative analysis. The recommended analysis incorporates the sampling weights in a nonstandard way and the sample clustering in the standard way.

CONCLUSIONS

Which particular aspects of the sampling design to use in the analysis of complex survey data and how to use them depend on certain features of the design. We give some guidelines for when to use the sample clustering and sample weights in the analysis.

Reinforcing and subjective effects of caffeine in normal human volunteers

The reinforcing and subjective effects of caffeine (100 and 300 mg, PO) were determined in a group of 18 normal, healthy adults. Subjects (eight females, ten males) were light to moderate users of caffeine, and had no history of drug abuse. A discrete-trial choice procedure was used in which subjects were allowed to choose between the self-administration of color-coded capsules containing either placebo or caffeine. The number of times caffeine was chosen over placebo was used as the primary index of reinforcing efficacy. Subjective effects were measured before and several times after capsule ingestion. The low dose of caffeine was chosen on 42.6% of occasions, not significantly different from chance (50%). The high dose of caffeine was chosen on 38.9% of occasions, significantly less than expected by chance, indicating that this dose served as a punisher. Both doses of caffeine produced stimulant-like subjective effects, with aversive effects such as increased anxiety predominating after the high dose. When subjects were divided into groups of caffeine-sensitive choosers and nonchoosers, a consistent relationship emerged between caffeine choice and subjective effects; nonchoosers reported primarily aversive effects after caffeine (increased anxiety and dysphoria), whereas choosers reported stimulant and "positive" mood effects. When compared with previous findings, these results demonstrate that caffeine is less reinforcing than amphetamine and related psychomotor stimulants.

Psychophysiological aspects of caffeine consumption

Caffeine may be the psychoactive compound most widely used in the United States. Caffeine appears in coffee, tea, cola drinks, chocolate bars and cocoa, cold and diet medications, and sleep-prevention compounds; the amount of caffeine varies in different substances and according to preparations. Research on caffeine's effects on alcoholic drinks, alertness, anxiety, heart rate, performance, and sleep is reviewed. Caffeine is usually not harmful, although long-range effects of caffeine have not been thoroughly investigated. Caffeine's effects often have been studied by means of ingestion of coffee but substances other than caffeine may be active in coffee and tea. The placebo effect contributes to some of the effects experienced by coffee-caffeine users.

Coffee drinking among Finnish youth

The suggestion that coffee may have negative health effects has made coffee-drinking habits medically interesting. This paper reports upon coffee use among young people and describes how coffee-users differ from non-users. Data comes from questionnaires from representative nationwide samples of 12-18-year-old Finnish youth in 1977-1985. Their coffee use decreased from 1977 to 1985, and the decrease could be seen in all age and socio-demographic groups studied. In 1981, 35% of the girls and 45% of the 12-year-old boys drank coffee daily. For 18-year-olds the corresponding percentages were 67 and 75, and the mean number of cups consumed per day was 2.3 and 3.1. Compared to the non-users, the coffee-users were from lower social classes, lived more often in the countryside, and had poorer school achievement. Health-damaging habits such as smoking were more common among the coffee-users, their perceived health was somewhat poorer, and they seemed to mature earlier. The difference in regard to health disappeared after adjusting for differences in socio-demographic background and health habits. The heavy users (four cups or more a day) usually differed more from the non-users than did the moderate users (one to three cups daily).

Plasma adenosine levels: measurement in humans and relationship to the anxiogenic effects of caffeine

The effects of caffeine on plasma adenosine were examined in eight healthy normal volunteers. Subjects were randomly administered on 4 separate days, in a double-blind fashion, either placebo or three different doses of caffeine (240, 480, and 720 mg). Adenosine concentrations, measured by high performance liquid chromatography, were in the micromolar range when samples were drawn into tubes containing dipyridamole to prevent adenosine reuptake by red blood cells. Plasma adenosine levels did not change after caffeine administration. The effects of caffeine on anxiety were related to changes in plasma caffeine but not plasma adenosine levels. The potential interest of caffeine as a chemical model of anxiety is discussed.