The effects of caffeine and evening meals on sleep and performance, mood and cardiovascular functioning the following day

Sensory evaluation and chemical composition of Solanum nigrum and Solanum torvum herbal tea and spice

Herbal teas are ingested for various purposes and by diverse populations across the globe. There is a growing recognition among individuals of the advantages associated with the use of this beverage, leading to a heightened demand for the manufacture of herbal tea derived from therapeutic plants. Spices on the other hand add flavour to food but could pose harm if it is high in phytates and oxalates. The objective of this study was to develop natural spices and herbal tea with health beneficial properties using Solanum nigrum and Solanum torvum berries. Herbal tea samples from S. nigrum were prepared by sorting berries, maceration, divided into two (fermenting at 18 °C and non-fermenting) and dried at 60 °C for 12 h in a hot oven. Spices from S. torvum and S. nigrum were prepared by removing the berries from the stalk, freeze-drying and smooth milling into fine powder. In addition, antinutrient, phytochemical and sensory evaluation studies were conducted on these spices and herbal teas. A nine-point hedonic scale was utilized for the purpose of conducting a consumer acceptability sensory evaluation test using 101 untrained panelists. Data was then analyzed by t-test, one-way analysis of variance (ANOVA) and the level of significance (p < 0.05) was assessed using Tukey's and Dunnett's multiple comparison tests. The panellists expressed a favourable perception towards Solanum nigrum unripe unfermented green herbal tea (6.65 ± 2.08) as compared to the other formulated teas due to the components working together in a way that produces a nice tea sample. Both Solanum nigrum and Solanum torvum spices contained various levels of catechins, saponins, flavonoids, oxalates, phytates and tannins comparable to literature. The herbal tea samples exhibited a range of catechin content, varying from 0.255 to 0.756 mg/g. The antioxidant activity of the various herbal tea samples ranged from 66.37 ± 0.24 to 78.53 ± 0.18 µg/mL GAE as determined by the DPPH free radical assay Fermented black herbal teas recorded higher total phenols (2.80 ± 0.09d), total flavonoids (21.84 ± 1.84c) and showed greater antioxidant activity (78.53 ± 0.18a) as compared to the unfermented green herbal teas. The process of fermentation resulted in a decrease in pH from 7.22 to 6.53 within a period of 12 h. The Total Titratable Acidity (TTA) grew as the fermentation period progressed, whereas the Total Soluble Solids (TSS) decreased. Phytates were the least antinutrients among the two Solanum species accounting for 0.02 mg/100 g and 0.03 mg/100 g in S. torvum berries (STBs) and (S. nigrum berries) SNBs respectively.

Diet and sleep health: a scoping review of intervention studies in adults

BACKGROUND

Recent research has demonstrated an association between dietary intake and sleep health that can influence chronic disease risk factors. A scoping review of research studies investigating dietary intake and sleep was undertaken to determine the extent and scope of research in laboratory-based, free-living and mixed settings. Additionally, this review determines how well subpopulations and geographical locations are represented and the methodologies used to assess outcome measures.

METHODS

Five online databases were used to identify papers published between 1970 and 2017. Included studies were those conducted in adults and reported both outcomes of interest: (i) sleep health, including sleep restriction and sleep hygiene and (ii) dietary outcomes, including altered nutrients, dietary patterns and supplements.

RESULTS

In total, 129 publications were included with the majority being dietary interventions investigating sleep outcomes (n = 109) with fewer being sleep interventions investigating and reporting dietary outcomes (n = 20). Dietary interventions were most often carried out in free-living environments, in contrast to sleep interventions that were most often carried out in laboratory-based environments. The majority of dietary interventions investigated use of a supplement (n = 66 studies), which was predominantly caffeine (n = 49). Sleep interventions investigated sleep duration only, with the majority (n = 17) investigating the effect of partial sleep restriction under 5.5 h per night on dietary intake, while three studies investigating total sleep deprivation.

CONCLUSIONS

Investigating broader aspects of dietary such as overall diet quality and dietary patterns and other components of sleep health such as quality,  timing and sleep hygiene are important aspects for future research.

Daily Patterns of Caffeine Intake and the Association of Intake with Multiple Sociodemographic and Lifestyle Factors in US Adults Based on the NHANES 2007-2012 Surveys

BACKGROUND

Caffeine increases alertness when consumed in single servings of various products including coffee, tea, soft drinks, and energy drinks. Although not a nutrient, caffeine is consumed by 90% of the adult population in the United States.

OBJECTIVE

This study examined the daily pattern of caffeine intake and its relationship to multiple demographic variables.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) 2007-2012 (adults aged 19+ years; n=16,173) were used to determine the time of day at which caffeine is consumed and demographic factors associated with intake. Regression analyses characterized factors associated with caffeine intake including sex, age, ethnicity, education, smoking status, physical activity, employment status, total work hours, alcohol, and energy intake.

RESULTS

Mean adult per capita caffeine intake was 169±4 mg/d (mean±standard error). Most caffeine (70%) was consumed before noon, often at breakfast, and intake decreased progressively over the day, with little consumed after 9:00 pm. Intake was associated with age, ethnicity, smoking status, total calorie intake, and work hours (P<0.01) but not physical activity, economic status, education level, or employment status. Variables with the largest associations with intake were, respectively, ethnicity and age. Non-Hispanic black individuals consumed the smallest amounts (80±2 mg/d), non-Hispanic white individuals consumed the greatest amounts (194±3 mg/d), and Asian individuals (126±7 mg/d) and Hispanic individuals consumed intermediate amounts (127±3 mg/d). Middle-aged individuals (aged 50 to 54 years) consumed more caffeine (211±6 mg/d) than younger (107±4 mg/d, aged 20 to 24 years) and older individuals (153±4 mg/d, aged 75 to 79 years).

CONCLUSION

Most caffeine is consumed in the morning, when alertness is lowest, and very little in the evening before sleep. Ethnicity and age were the variables most strongly associated with intake; work hours, occupation, energy and alcohol intake, and smoking were also associated with intake. Because caffeine increases alertness, it is not surprising that its pattern of consumption and factors associated with its intake vary from those of most other food constituents.

Caffeine: Friend or Foe?

The debate on the safety of and regulatory approaches for caffeine continues among various stakeholders and regulatory authorities. This decision-making process comes with significant challenges, particularly when considering the complexities of the available scientific data, making the formulation of clear science-based regulatory guidance more difficult. To allow for discussions of a number of key issues, the North American Branch of the International Life Sciences Institute (ILSI) convened a panel of subject matter experts for a caffeine-focused session entitled "Caffeine: Friend or Foe?," which was held during the 2015 ILSI Annual Meeting. The panelists' expertise covered topics ranging from the natural occurrence of caffeine in plants and interindividual metabolism of caffeine in humans to specific behavioral, reproductive, and cardiovascular effects related to caffeine consumption. Each presentation highlighted the potential risks, benefits, and challenges that inform whether caffeine exposure warrants concern. This paper aims to summarize the key topics discussed during the session.

Chronic but not acute treatment with caffeine attenuates traumatic brain injury in the mouse cortical impact model

Caffeine, the most consumed psychoactive drug and non-specific adenosine receptor antagonist, has recently been shown to exert a neuroprotective effect against brain injury in animal models of Parkinson's disease (PD) and stroke. However, the effects of caffeine on traumatic brain injury (TBI) are not known. In this study, we investigated the effects of acute and chronic caffeine treatment on brain injury in a cortical-impact model of TBI in mice. Following TBI, neurological deficits, cerebral edema, as well as inflammatory cell infiltration were all significantly attenuated in mice pretreated chronically (for 3 weeks) with caffeine in drinking water compared with the mice pretreated with saline. Furthermore, we found that chronic caffeine treatment attenuated glutamate release and inflammatory cytokine production, effects that were correlated with an upregulation of brain A1 receptor mRNA. By contrast, acute treatment with caffeine (i.p. injection, 30 min before TBI) was not effective in protecting against TBI-induced brain injury. These results suggest that chronic (but not acute) caffeine treatment attenuates brain injury, possibly by A1 receptor-mediated suppression of glutamate release and inhibition of excessive inflammatory cytokine production. These results highlight the potential benefit of chronic caffeine intake for preventing TBI and provide a rationale for the epidemiological investigation of the potential association between TBI and human caffeine intake.

Dietary caffeine, performance and mood: enhancing and restorative effects after controlling for withdrawal reversal

This study aimed to determine whether sustained (i.e. dietary) use of caffeine has net effects on performance and mood compared with sustained abstinence, and whether dietary caffeine restores performance and mood adversely affected by sleep restriction. Participants (n = 96) alternated weekly between ingesting placebo and caffeine (1.75 mg/kg) three times daily for 4 consecutive weeks, while either rested or sleep restricted. Performance involved either a single task requiring sustained vigilance or a varied battery of brief psychomotor and cognitive tasks, and mood was assessed using the Profile of Mood States. Caffeine had no significant net enhancing effects for either performance or mood when participants were rested, and produced no net restorative effects when performance and mood were degraded by sleep restriction.

Hemodynamic effects of dietary caffeine, sleep restriction, and laboratory stress

This study examined the separate and interactive effects of caffeine, sleep restriction, and task-induced laboratory stress in 96 healthy male and female volunteers. Participants alternated weekly between ingesting placebo and caffeine (1.75 mg/kg) three times daily for 4 consecutive weeks, while being either rested or sleep restricted. Finapres measurements of blood pressure, cardiac output, and total peripheral resistance showed that caffeine produced persistent blood pressure increases with a vascular hemodynamic profile. Sleep restriction produced a pronounced vascular response not associated with appreciable changes in blood pressure, whereas blood pressure increases induced by cognitive activity showed mixed cardiac and vascular responses. The findings suggest that life-long dietary caffeine may contribute significantly to the development of cardiovascular disease.

Effects of dietary caffeine on mood when rested and sleep restricted

Prolonged use of caffeine can lead to physical dependence evidenced by characteristic withdrawal symptoms during abstinence. Debate exists as to whether mood enhancement by caffeine represents a net effect or merely the restoration of abstinence-induced mood decrements. One aim of this study was to determine the net effects on mood of dietary caffeine compared with prolonged abstinence. In addition, the study aimed to determine whether caffeine restores mood degraded by a non-caffeine source, namely, sleep restriction. A double-blind placebo-controlled cross-over design was employed in which 48 male and female volunteers alternated weekly between ingesting placebo and caffeine (1.75 mg/kg) three times daily for 4 consecutive weeks, while being either rested or sleep restricted. Mood was assessed using a computerized version of the profile of mood states (POMS), giving scores for overall mood and six mood dimensions. Gender had small effects on mood, whereas all mood dimensions were markedly adversely affected by sleep restriction. Caffeine had no significant net enhancing effects on mood when participants were rested, and produced no net restorative effects when mood was degraded by sleep restriction. On the contrary, caffeine-induced decrements in mood were observed during both conditions of rest and sleep restriction.

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.

What is the role of food in preventing depression and improving mood, performance and cognitive function?

Slow weight reduction in overweight women can help to elevate mood. Omega 3 polyunsaturated fatty acids may play a role in mental wellbeing. Eating breakfast regularly leads to improved mood, better memory, more energy and feelings of calmness. Eating regular meals and nutritious afternoon snacks may improve cognitive performance.

Efficacy and safety of herbal stimulants and sedatives in sleep disorders

World-wide use of herbal medicines is increasing, following regulatory and manufacturing developments. Herbs are attractive alternative medications to many patients with sleep disorders, who may be averse to using conventional drugs. We review here the most common herbal stimulants and sedatives. Caffeine, in herbal teas, black tea, coffee, soft drinks and pharmaceuticals, is used widely to control sleepiness, but more research is needed on its use in sleep disorders. Ephedra, and its constituent ephedrine, are used in both stimulant and weight loss preparations, sometimes with caffeine; safety concerns have arisen with this practice. Yohimbe is another herb used in stimulant and body-building preparations which has safety concerns. Asian and Siberian ginseng have been traditionally used for fatigue, and have some supportive experimental evidence for this use. Herbal sedatives also have some evidence for efficacy; the observations that certain plant flavonoid compounds bind to benzodiazepine receptors adds interest to their use. Valerian and kava have received the most research attention; both have decreased sleep onset time and promoted deeper sleep in small studies, and kava also shows anxiolytic effects. German chamomile, lavender, hops, lemon balm and passionflower are reputed to be mild sedatives but need much more experimental examination.

Effects of caffeine on cognition and mood without caffeine abstinence

The objective of this study was to evaluate the effects of low doses (75 mg and 150 mg) of caffeine on mood and cognition in healthy people, with minimal abstinence of 1 h from caffeine. Improvements were obtained in cognition for attention, problem solving and delayed recall, but not immediate recall or working memory, but performance in the placebo condition was close to the maximum, giving little margin for improvement. For mood, there were statistically significant increase in clearheadedness, happiness and calmness and decreases in tenseness. These mood and performance-enhancing effects of caffeine cannot be seen as representing an alleviation of deficits induced by caffeine abstinence, because there was only minimal deprivation from caffeine.

A comparison of the acute effects of a low dose of alcohol on mood and performance of healthy volunteers and subjects with upper respiratory tract illnesses

An experiment was carried out to determine whether a low dose of alcohol produced different behavioural effects in healthy volunteers to those suffering from an upper respiratory tract illness. Ninety-nine subjects were tested, with 48 subjects being assigned to the alcohol condition and 51 to the juice only condition. A dose of 1.5 ml of vodka per kg body weight was used and the alcohol manipulation was double-blind. Approximately half of the subjects in each condition were healthy and the others had upper respiratory tract illnesses, probably colds. Subjects with colds reported an increase in negative affect and were slower at performing psychomotor tasks. Few main effects of alcohol were obtained. Of major interest were the interactions between health status and alcohol conditions. The alcohol improved the mood of healthy subjects but produced greater negative moods in subjects with colds. Similarly, performance of selective and sustained attention tasks showed different effects of alcohol in healthy and ill subjects.