Dr Lauren Owen

<i>Aims:</i> Our group has conducted several Internet investigations into the biobehavioural effects of self-reported recreational use of MDMA (3,4-methylenedioxymethamphetamine or Ecstasy) and other psychosocial drugs. Here we report a new study examining the relationship between self-reported Ecstasy use and traces of MDMA found in hair samples. <i>Methods:</i> In a laboratory setting, 49 undergraduate volunteers performed an Internet-based assessment which included mood scales and the University of East London Drug Use Questionnaire, which asks for history and current drug use. They also provided a hair sample for determination of exposure to MDMA over the previous month. <i>Results:</i> Self-report of Ecstasy use and presence in hair samples were consistent (p < 0.00001). Both subjective and objective measures predicted lower self-reported ratings of happiness and higher self-reported stress. Self-reported Ecstasy use, but not presence in hair, was also associated with decreased tension. <i>Conclusion:</i> Different psychoactive drugs can influence long-term mood and cognition in complex and dynamically interactive ways. Here we have shown a good correspondence between self-report and objective assessment of exposure to MDMA. These data suggest that the Internet has potentially high utility as a useful medium to complement traditional laboratory studies into the sequelae of recreational drug use.

Over the past four or five decades, there has been increasing interest in the neurochemical regulation of cognition. This field received considerable attention in the 1980s, with the identification of possible cognition enhancing agents or “smart drugs”. Even though many of the optimistic claims for some agents have proven premature, evidence suggests that several metabolic agents may prove to be effective in improving and preserving cognitive performance and may lead to better cognitive aging through the lifespan. Aging is characterized by a progressive deterioration in physiological functions and metabolic processes. There are a number of agents with the potential to improve metabolic activity. Research is now beginning to identify these various agents and delineate their potential usefulness for improving cognition in health and disease. This review provides a brief overview of the metabolic agents glucose, oxygen, pyruvate, creatine, and l-carnitine and their beneficial effects on cognitive function. These agents are directly responsible for generating ATP (adenosine triphosphate) the main cellular currency of energy. The brain is the most metabolically active organ in the body and as such is particularly vulnerable to disruption of energy resources. Therefore interventions that sustain adenosine triphosphate (ATP) levels may have importance for improving neuronal dysfunction and loss. Moreover, recently, it has been observed that environmental conditions and diet can affect transgenerational gene expression via epigenetic mechanisms. Metabolic agents might play a role in regulation of nutritional epigenetic effects. In summary, the reviewed metabolic agents represent a promising strategy for improving cognitive function and possibly slowing or preventing cognitive decline.

Accurate and robust estimation of individuals’ basal glucose level is a crucial measure in nutrition research but is typically estimated from one or more morning fasting samples. The use of Continuous Glucose Monitoring (CGM) devices presents an opportunity to define more robust basal glucose levels, which estimates can be generalized to any time of the day. However, to date, no standardized method has been delineated. The current paper seeks to define a reliable algorithm to characterize the individual’s basal glucose level over 24 h from CGM measurements. Data drawn from four nutritional intervention studies performed on adults free from chronic diseases were used to define that basal glucose levels were optimally estimated using the 40th percentile of the previous 24 h CGM data. This simple algorithm provides a Continuous Glucose Baseline over 24 h (24 h-CGB) that is an unbiased and highly correlated estimator (r = 0.86, p-value < 0.01) of standard fasting glucose. We conclude that 24-CGB can provide reliable basal glucose estimates across the day while being more robust to interference than standard fasting glucose, adaptable to evolving daily routines and providing useful reference values for free-living nutritional intervention research in non-diabetic individuals.

Glucose facilitation of cognitive function has been widely reported in previous studies (including our own). However, several studies have also failed to detect glucose facilitation. There is sparsity of research examining the factors that modify the effect of glucose on cognition. The aims of the present study were to (1) demonstrate the previously observed enhancement of cognition through glucose administration and (2) investigate some of the factors that may exert moderating roles on the behavioural response to glucose, including glucose regulation, body composition (BC) and hypothalamic–pituitary–adrenal axis response. A total of twenty-four participants took part in a double-blind, placebo-controlled, randomised, repeated-measures study, which examined the effect of 25 and 60 g glucose compared with placebo on cognitive function. At 1 week before the study commencement, all participants underwent an oral glucose tolerance test. Glucose facilitated performance on tasks of numeric and spatial working memory, verbal declarative memory and speed of recognition. Moderating variables were examined using several indices of glucoregulation and BC. Poorer glucoregulation predicted improved immediate word recall accuracy following the administration of 25 g glucose compared with placebo. Those with better glucoregulation showed performance decrements on word recall accuracy following the administration of 25 g glucose compared with placebo. These findings are in line with accumulating evidence that glucose load may preferentially enhance cognition in those with poorer glucoregulation. Furthermore, the finding that individuals with better glucoregulation may suffer impaired performance following a glucose load is novel and requires further substantiation.

A systematic review was conducted to evaluate whether chocolate or its constituents were capable of influencing cognitive function and/or mood. Studies investigating potentially psychoactive fractions of chocolate were also included. Eight studies (in six articles) met the inclusion criteria for assessment of chocolate or its components on mood, of which five showed either an improvement in mood state or an attenuation of negative mood. Regarding cognitive function, eight studies (in six articles) met the criteria for inclusion, of which three revealed clear evidence of cognitive enhancement (following cocoa flavanols and methylxanthine). Two studies failed to demonstrate behavioral benefits but did identify significant alterations in brain activation patterns. It is unclear whether the effects of chocolate on mood are due to the orosensory characteristics of chocolate or to the pharmacological actions of chocolate constituents. Two studies have reported acute cognitive effects of supplementation with cocoa polyphenols. Further exploration of the effect of chocolate on cognitive facilitation is recommended, along with substantiation of functional brain changes associated with the components of cocoa. © 2013 International Life Sciences Institute.

Rationale: Alcohol hangover may be defined as an adverse effect of heavy alcohol consumption present after sufficient time has elapsed for the alcohol to have been eliminated from the blood. Understanding how hangover may impair performance is important for public safety; yet, there is relatively little hangover research. This paper outlines good practice for future studies. Objectives: This paper presents a critical analysis of hangover methodology for surveys or studies of effects on cognition with human subjects and provides suggestions for optimum research practice for laboratory-based and naturalistic alcohol hangover studies. Results: Four hangover symptom scales have been developed and subjected to psychometric testing. For retrospective assessment, we recommend the Hangover Symptoms Scale (HSS) or the Alcohol Hangover Severity Scale (AHSS). For concurrent assessment of hangover symptoms, we recommend either the Acute Hangover Scale (AHS), the five-item version of the HSS, or the AHSS. In research aiming to assess the cognitive effects of alcohol hangover, we suggest focusing on the cognitive domains of attention, memory and executive function, and we specify a number of tests within these cognitive domains that are likely to be sensitive to any decrements due to hangover. Finally, we argue that naturalistic studies should assess biological markers to improve the accuracy of estimates of alcohol consumption. Specifically, we recommend the assessment of ethyl glucuronide (EtG) for this purpose. Conclusions: Recommendations are made with respect to assessing hangover symptoms, cognitive effects of hangover and biological markers of alcohol consumption. © 2014 Springer-Verlag Berlin Heidelberg.

Rationale: Over the last decade, Asian ginseng (Panax ginseng) has been shown to improve aspects of human cognitive function. American ginseng (Panax quinquefolius) has a distinct ginsenoside profile from P. ginseng, promising cognitive enhancing properties in preclinical studies and benefits processes linked to human cognition. Objectives: The availability of a highly standardised extract of P. quinquefolius (Cereboost™) led us to evaluate its neurocognitive properties in humans for the first time. Methods: This randomised, double-blind, placebo-controlled, crossover trial (N=32, healthy young adults) assessed the acute mood, neurocognitive and glycaemic effects of three doses (100, 200 400 mg) of Cereboost™ (P. quinquefolius standardised to 10.65% ginsenosides). Participants' mood, cognitive function and blood glucose were measured 1, 3 and 6 h following administration. Results: There was a significant improvement of working memory (WM) performance associated with P. quinquefolius. Corsi block performance was improved by all doses at all testing times. There were differential effects of all doses on other WM tasks which were maintained across the testing day. Choice reaction time accuracy and 'calmness' were significantly improved by 100 mg. There were no changes in blood glucose levels. Conclusions: This preliminary study has identified robust working memory enhancement following administration of American ginseng. These effects are distinct from those of Asian ginseng and suggest that psychopharmacological properties depend critically on ginsenoside profiles. These results have ramifications for the psychopharmacology of herbal extracts and merit further study using different dosing regimens and in populations where cognition is fragile. © 2010 The Author(s).

Purpose: In the current study we evaluated a blend of ingredients containing mulberry leaf extract (to lower postprandial glucose of the evening meal), tryptophan (facilitator of the sleep initiation) to benefit sleep initiation and quality in adults with self-reported difficulties with sleep initiation. Methods: Forty-three adults aged between 25 and 50 years enrolled in a randomized, crossover, double-blind, controlled trial. Participants received standardized meals with a glycemic load of 55 ± 10% and were assigned to receive treatment comprising a combination of mulberry leaf extract (750 mg), whey protein containing 120 mg tryptophan, zinc (1.35 mg), magnesium (12.6 mg), vitamin B3 (1.93 mg) and B6 (0.135 mg) and control (4 g wheat protein hydrolysate). Each intervention phase lasted 14 days separated by a washout period of 28 days. The primary outcomes were actigraphy-measured sleep onset latency and sleep efficiency. Secondary outcomes included continuous glycemic responses, mood, and cognition. Results: A linear mixed model intention-to-treat analysis conducted on 42 participants found that the treatment reduced sleep onset latency (actigraphy: −3.82 mins, p = 0.026; self-report: −3.09 mins, p = 0.048). Treatment significantly reduced evening meal’s postprandial glucose response (incremental area under the curve, mmol/L*min) at 1 hour by 21% (p < 0.001), incremental maximum concentration by 16% (p = < 0.001) and nocturnal glucose variation over the 14-day period. Participants on treatment reported improved sleep quality (Karolinska Sleepiness Scale, −0.17, p = 0.041) and feeling more relaxed (Brief Mood Introspection Scale, −0.4, p = 0.003) the next morning compared to when taking the control. Additionally, the treatment improved the vigor dimension on the Profile of Mood Scale (0.8, p = 0.038). No effects were observed on the cognitive performance. Lowering postprandial glucose significantly mediated the treatment effect of lowering sleep onset latency and lower nocturnal glucose variation was also associated with improved sleep quality and next-day positive mood. Conclusion: The evening meal supplement benefited sleep initiation and quality, and also improved post wake mood in adults. Trial Registration: Registration number of Clinical Trial - ClinicalTrials.gov NCT05372900

Many people take nutraceuticals and supplements in the belief that they improve alertness or offset cognitive decline. Over the past decade or so there has been a large increase in the amount of research examining the links between diet, nutraceuticals and psychological function. This has revealed cognitive benefits from a number of sources. For example glucose administration improves cognitive functioning, and the mechanisms underlying this effect are increasingly understood. The glycaemic index (GI) of a food can also influence mental performance. There is also good evidence that certain dietary supplements have cognition-enhancing properties. These include endogenous substances which support neural structure and function (amino acids and polyunsaturated fatty acids). Other substances which improve cognitive function appear to do so by increasing energy availability to the brain either directly (e.g. creatine) or via improving cardiovascular functioning (e.g. CoQ10). Additionally certain herbal extracts can improve mood and cognitive function (in this chapter we use sage and lemon balm as examples). These effects are probably mediated by multiple actions including direct neurotransmitter modulation. Interestingly in the case of herbs, the behavioural effects are often in keeping with their usage in traditional medicine systems. There are numerous challenges in understanding the effects of nutraceuticals on cognition. As well as the issue of standardisation, there is the problem of understanding the mechanisms and underlying effects which involve multiple processes. These challenges are increasingly being met by new technologies which enhance our understanding of brain functioning. © 2011 Woodhead Publishing Limited All rights reserved.

The effect of alcohol hangover on cognitive processing has received little attention. We explored the effect of alcohol hangover on choice response time (RT), a dominant dependent variable (DV) in cognitive research. Prior research of the effect of hangover on RT has produced mixed findings; all studies reviewed relied exclusively on estimates of central tendency (e.g. mean RT), which has limited information value. Here we present novel analytical methods by going beyond mean RT analysis. Specifically, we examined performance in hangover conditions ( n =31) across the whole RT distribution by fitting ex-Gaussian models to participant data, providing a formal description of the RT distribution. This analysis showed detriments to performance under hangover conditions at the slower end of the RT distribution and increased RT variance under hangover conditions. We also fitted an explicit mathematical process model of choice RT – the diffusion model – which estimates parameters reflecting psychologically-meaningful processes underlying choice RT. This analysis showed that hangover reduced information processing efficiency during response selection, and increased response caution; changes in these parameters reflect hangover affecting core decisional-components of RT performance. The implications of the data as well as the methods used for hangover research are discussed.

The brain has a high metabolic rate and its metabolism is almost entirely restricted to oxidative utilisation of glucose. These factors emphasise the extreme dependence of neural tissue on a stable and adequate supply of glucose. Whereas initially it was thought that only glucose deprivation (i.e. under hypoglycaemic conditions) can affect brain function, it has become apparent that low-level fluctuations in central availability can affect neural and consequently, cognitive performance. In the present paper the impact of diet-based glycaemic response and glucose regulation on cognitive processes across the lifespan will be reviewed. The data suggest that although an acute rise in blood glucose levels has some short-term improvements of cognitive function, a more stable blood glucose profile, which avoids greater peaks and troughs in circulating glucose is associated with better cognitive function and a lower risk of cognitive impairments in the longer term. Therefore, a habitual diet that secures optimal glucose delivery to the brain in the fed and fasting states should be most advantageous for the maintenance of cognitive function. Although the evidence to date is promising, it is insufficient to allow firm and evidence-based nutritional recommendations. The rise in obesity, diabetes and metabolic syndrome in recent years highlights the need for targeted dietary and lifestyle strategies to promote healthy lifestyle and brain function across the lifespan and for future generations. Consequently, there is an urgent need for hypothesis-driven, randomised controlled trials that evaluate the role of different glycaemic manipulations on cognition.

Rationale Previous research has identified a number of factors that appear to moderate the behavioural response to glucose administration. These include physiological state, dose, types of cognitive tasks used and level of cognitive demand. Another potential moderating factor is the length of the fasting interval prior to a glucose load. Objectives Therefore, we aimed to examine the effect of glucose dose and fasting interval on mood and cognitive function. Methods The current study utilised a double-blind, placebo-controlled, balanced, six period crossover design to examine potential interactions between length of fasting interval (2 versus 12 hours) and optimal dose for cognition enhancement. Results Results demonstrated that the higher dose (60 g) increased working memory performance following an overnight fast, whereas the lower dose (25 g) enhanced working memory performance following a 2-h fast. Conclusions The data suggest that optimal glucose dosage may differ under different conditions of depleted blood glucose resources. In addition, glucoregulation was observed to be a moderating factor. However, further research is needed to develop a model of the moderating and mediating factors under which glucose facilitation is best achieved. © 2011 Springer-Verlag.

Mental, neurological and substance-use disorders presently represent the greatest global burden of disease. Likewise, depression and other psychopathologies are elevated risk comorbidities of other health hazards, such as obesity. Nutrition has been implicated in behaviour, mood and in the pathology and treatment of mental illness. In this brief editorial, we aim to set the scale of the problem in context and overview advances and recent evidence linking nutrition to psychological outcomes. The purpose of the 2016 Nutrition Society Winter Meeting, ‘Diet, nutrition and mental health and wellbeing’ was to review where the evidence is strong, where there are unmet needs for research and to draw together the communities working in this area to share their findings. The papers presented demonstrated clear advancements that are being made in this field. The meeting illustrated compelling support for nutrition as a modifiable risk factor. The present research in the field and evidence presented at the 2016 Nutrition Society Winter Meeting lead us to postulate that even interventions with relatively modest effect sizes may plausibly and significantly curtail the disease burden of mental and neurological disease by food- and nutrient-based approaches.

There are a number of agents which are believed to impact on metabolic functions which may ultimately impact on neuronal cell survival and cognitive function. Aging is characterized by a progressive deterioration in physiological functions and metabolic processes. Regimes that buffer intracellular energy levels may impede the progression of the neurodegenerative process. This chapter focuses on some of the metabolic agents that may prove to be effective in combating neurodegeneration and lead to better cognitive aging through the life span. The metabolic agents specically focused on in this chapter are glucose and oxygen, pyruvate, creatine, and L-carnitine. Each of these agents is directly responsible for generating adenosine triphosphate (ATP), the molecular unit of currency of intracellular energy transfer. Their roles as cognitive agents are explored.

Aims: Positive family history of alcohol use disorder (FHP), a variable associated with propensity for alcohol use disorder (AUD), has been linked with elevated hangover frequency and severity, after controlling for alcohol use. This implies that hangover experiences may be related to AUD. However, inadequate control of alcohol consumption levels, low alcohol dose and testing for hangover during the intoxication phase detract from these findings. Here, we present further data pertinent to understanding the relationship between family history and alcohol hangover. Methods: Study 1 compared past year hangover frequency in a survey of 24 FHP and 118 family history negative (FHN) individuals. Study 2 applied a quasi-experimental naturalistic approach assessing concurrent hangover severity in 17 FHP and 32 FHN individuals the morning after drinking alcohol. Both studies applied statistical control for alcohol consumption levels. Results: In Study 1, both FHP status and estimated blood alcohol concentration on the heaviest drinking evening of the past month predicted the frequency of hangover symptoms experienced over the previous 12 months. In Study 2, estimated blood alcohol concentration the previous evening predicted hangover severity but FHP status did not. Conclusions: FHP, indicating familial risk for AUD, was not associated with concurrent hangover severity but was associated with increased estimates of hangover frequency the previous year.

Ratings of appetite are commonly used to assess appetite modification following an intervention. Subjectively rated appetite is a widely employed proxy measure for energy intake (EI), measurement of which requires greater time and resources. However, the validity of appetite as a reliable predictor of EI has not yet been reviewed systematically. This literature search identified studies that quantified both appetite ratings and EI. Outcomes were predefined as: (1) agreement between self-reported appetite scores and EI; (2) no agreement between self-reported appetitescores and EI. The presence of direct statistical comparison between the endpoints, intervention type and study population were also recorded. 462 papers were included in this review. Appetite scores failed to correspond with EI in 51.3% of the total studies. Only 6% of all studies evaluated here reported a direct statistical comparison between appetite scores and EI. χ

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Background: A phasic dysregulation of mitochondrial bioenergetics may operate in bipolar disorder, increased in mania and decreased in depression. We aimed to examine efficacy of two add-on treatments in bipolar depression: N-acetylcysteine (NAC) and NAC with a combination of nutraceutical agents that may increase mitochondrial biogenesis. Methods: A three-arm 16-week, double-blind, randomised, placebo-controlled trial, adjunctive to usual treatment, was conducted. Participants (n = 181) with bipolar disorder and current depressive symptoms were randomised to 2000 mg/day NAC (n = 59), 2000 mg/day NAC with the combination nutraceutical treatment (CT, n = 61), or placebo (n = 61). The primary outcome was change in Montgomery-Åsberg Depression Rating Scale (MADRS) total score from baseline to week 16. Young Mania Rating Scale, Clinical Global Impression (CGI)-Improvement and CGI-Severity scales, Patient Global Impression scale, Social and Occupational Functioning Assessment Scale (SOFAS), Longitudinal Interval Follow-Up Evaluation - Range of Impaired Functioning Tool (LIFE-RIFT), and Quality of Life Enjoyment, and Satisfaction Questionnaire Short Form (Q-LES-Q-SF) were secondary outcomes. Results: One hundred forty-eight participants had post-randomisation data and were analysed (NAC = 52, CT = 47, Placebo = 49). No between-group differences were found for the rate of change between baseline and 16 weeks on any of the clinical and functioning variables. Improvements in MADRS, BDRS, SOFAS, and LIFE-RIFT scores from baseline to the week 20 post-discontinuation visit were significantly greater in the CT group compared to those in the placebo. At week 20, the CGI-I was significantly lower in the CT group versus placebo. Gastrointestinal symptoms were significantly greater in the NAC than in the placebo group. Conclusions: These overall negative results, with no significant differences between groups detected at the primary outcome but some positive secondary signals, suggest either delayed benefit of the combination or an improvement of symptoms on withdrawal which warrants further exploration regarding the composition, mechanisms, and application of mitochondrial agents in illnesses characterised by mitochondrial dysfunction. Trial registration: ANZCTR (ACTRN12612000830897).

The original article [1] contained two minor errors. 1) Author, Chee H. Ng's middle initial was omitted; 2) The Competing Interests declaration omitted some information regarding author, Chee H. Ng. These two errors have since been corrected.

The 2010 Alcohol Hangover Research Group consensus paper defined a cutoff blood alcohol concentration (BAC) of 0.11% as a toxicological threshold indicating that sufficient alcohol had been consumed to develop a hangover. The cutoff was based on previous research and applied mostly in studies comprising student samples. Previously, we showed that sensitivity to hangovers depends on (estimated) BAC during acute intoxication, with a greater percentage of drinkers reporting hangovers at higher BAC levels. However, a substantial number of participants also reported hangovers at comparatively lower BAC levels. This calls the suitability of the 0.11% threshold into question. Recent research has shown that subjective intoxication, i.e., the level of severity of reported drunkenness, and not BAC, is the most important determinant of hangover severity. Non-student samples often have a much lower alcohol intake compared to student samples, and overall BACs often remain below 0.11%. Despite these lower BACs, many non-student participants report having a hangover, especially when their subjective intoxication levels are high. This may be the case when alcohol consumption on the drinking occasion that results in a hangover significantly exceeds their “normal” drinking level, irrespective of whether they meet the 0.11% threshold in any of these conditions. Whereas consumers may have relative tolerance to the adverse effects at their “regular” drinking level, considerably higher alcohol intake—irrespective of the absolute amount—may consequentially result in a next-day hangover. Taken together, these findings suggest that the 0.11% threshold value as a criterion for having a hangover should be abandoned.

Recent research found a significant and positive correlation between hangover severity and pain catastrophizing. The current study aimed to verify these findings. Data from N = 673 subjects with a mean (SD) age of 42.2 (19.1) years old (range: 18 to 87 years old) was evaluated. An online survey collected data on alcohol consumption and hangovers related to their heaviest drinking occasion between 15 January and 14 March 2020. When correcting for the amount of alcohol consumed, significant correlations were found between hangover severity and both sensitivity to pain (r = 0.085, p = 0.029) and pain catastrophizing (r = 0.095, p = 0.015). In addition, subjective intoxication correlated significantly with sensitivity to pain (r = 0.080, p = 0.041) and pain catastrophizing (r = 0.099, p = 0.011). Overall, the results were more pronounced in men than women, and the associations with pain catastrophizing were strongest for the subscale assessing rumination. In conclusion, although statistically significant, the observed correlations were of small magnitude. Nevertheless, the observations confirm previous findings that suggest a link between pain perception, alcohol consumption, and hangover severity, which warrants further investigation.

Alcohol hangover is a cause of considerable social and economic burden. Identification of predictors of alcohol hangover severity have the potential to contribute to reductions in costs associated with both absenteeism/presenteeism and health care. Pain catastrophising (PC) is the tendency to ruminate and describe a pain experience in more exaggerated terms. The current study examines the possibility that this cognitive coping strategy may influence experience of alcohol hangover. The aims of the current study were to (1) examine the relationship between hangover severity and PC, (2) explore and identify discreet factors within the Acute Hangover Scale (AHS) and (3) explore whether independent factors/dimensions of acute hangover are differentially predicted by PC. A retrospective survey (n = 86) was conducted in which participants completed the Acute Hangover Scale (AHS); the Pain Catastrophising Scale (PCS); a questionnaire pertaining to the amount of alcohol consumed; and a demographic information questionnaire. Regression analyses showed a significant relationship between PC and hangover severity scores and demonstrated that PC was, in fact, a stronger predictor of perceived hangover severity than estimated peak blood alcohol concentrations (eBACs). Factor analysis of the AHS scale, resulted in the identification of two distinct symptom dimensions; ‘Headache and thirst’, and ‘Gastric and cardiovascular’ symptoms. Regression analyses showed that both eBAC and PCS score were significantly associated with ‘Headache and thirst’. However, only PCS score was associated with ‘Gastric and cardiovascular’ symptoms. These novel findings implicate a role for cognitive coping strategies in self-reports of alcohol hangover severity, and may have implications for understanding behavioural response to hangover, as well as suggesting that hangover and PC may be important factors mediating the motivation to drink and/or abuse alcohol, with potential implications in addiction research. Furthermore, these findings suggest that distinct alcohol hangover symptoms may be associated with different mechanisms underlying the experience of alcohol hangover.

Food insecurity (a lack of stable access to nutritious food) is reliably associated with higher BMI, although the underlying mechanisms are unclear. Past research indicates that this relationship may, in part, be explained by the distress of being food insecure and using food as a coping mechanism. While previous work has focused on long-term food insecurity, the first COVID-19 national lockdown presented a unique opportunity to establish if the same relationships existed for individuals experiencing pandemic related food insecurity. Adults in the United Kingdom (N = 211) were recruited three months after the first UK lockdown via social media. They completed questionnaires on COVID-19 related food insecurity, physical stress, psychological distress, eating to cope, drinking to cope, diet quality, and changes in weight promoting eating behaviours (e.g. consuming larger portions, increased snacking) since the start of the lockdown. A structural equation model revealed that food insecurity was indirectly associated with changes in weight promoting eating behaviours. As predicted, the more instances of pandemic related food insecurity, the more distress individuals reported. Distress was then associated with eating as a way of coping, which in turn was associated with increases in weight promoting eating behaviours. Food insecurity was also indirectly associated with diet quality, but this was via distress only. These results reflect similar pathways observed in individuals reporting chronic food insecurity and strengthens the evidence that distress and eating to cope are generic mediators of food insecurity and eating behaviour.

Obesity and type 2 diabetes (T2D) are increasingly common worldwide. While these disorders have increased in prevalence over the past several decades, there has been a concomitant reduction in sleep duration. Short sleep duration has been associated with higher rates of obesity and T2D, and the causality of these associations and their directionality, continue to necessitate evaluation. In this review we consider the evidence that sleep is an intrinsic factor in the development of obesity and chronic metabolic disorders, such as insulin resistance and T2D, while evaluating a potential bi-directional association. We consider the evidence that diet and meal composition, which are known to impact glycemic control, may have both chronic and acute impact upon sleep. Moreover, we consider that postprandial nocturnal metabolism and peripheral glycemia may affect sleep quality. We propose putative mechanisms whereby acute effects of nighttime glucose excursions may lead to increased sleep fragmentation. We conclude that dietary manipulations, particularly with respect to carbohydrate quality, may confer sleep benefits. Future research may seek to evaluate the effectiveness of synergistic nutrient strategies to promote sleep quality, with particular attention to carbohydrate quality, quantity, and availability as well as carbohydrate to protein ratio.

There has been increasing interest in the effects of nutrition on cognitive performance and more specifically how cognitive performance can be optimised using nutritional interventions. The macronutrient glucose has particularly received attention and is perhaps most thoroughly researched in terms of its effects on cognition. The notion that oral glucose administration might facilitate mental performance was first proposed in the 1950s. Hafermann (1955) investigated the effects of glucose administration on school children and observed a distinct increase in cognitive performance, including performance in mathematics, and generally improved concentration. However, it was not until the mid-1980s that glucose effects on cognitive performance became more widely investigated (Gold, 1986).

It has been suggested that the memory enhancing effect of glucose follows an inverted U-shaped curve, with 25 g resulting in optimal facilitation in healthy young adults. The aim of this study was to further investigate the dose dependency of the glucose facilitation effect in this population across different memory domains and to assess moderation by interindividual differences in glucose regulation and weight. Following a double-blind, repeated measures design, 30 participants were administered drinks containing five different doses of glucose (0 g, 15 g, 25 g, 50 g, and 60 g) and were tested across a range of memory tasks. Glycaemic response and changes in mood state were assessed following drink administration. Analysis of the data showed that glucose administration did not affect mood, but significant glucose facilitation of several memory tasks was observed. However, dose–response curves differed depending on the memory task with only performance on the long-term memory tasks adhering largely to the previously observed inverted U-shaped dose–response curve. Moderation of the response profiles by interindividual differences in glucose regulation and weight was observed. The current data suggest that dose–response function and optimal dose might depend on cognitive domain and are moderated by interindividual differences in glucose regulation and weight.

Age-related cognitive decline (ARCD) and dementia are of increasing concern to an ageing population. In recent years, there has been considerable research focused on effective dietary interventions that may prevent or ameliorate ARCD and dementia. While a number of studies have considered the impact that dairy products may have on physiological health, particularly with regard to the metabolic syndrome and cardiovascular health, further research is currently needed in order to establish the impact that dairy products have in the promotion of healthy brain function during ageing. The present review considers the available evidence for the positive effects of dairy products on the metabolic syndrome and glucose regulation, with consideration of the implications for neurocognitive health. A literature search of current (September 2010) meta-analyses/reviews and original research regarding dairy products and cognition was conducted through SCOPUS using the following search terms for dairy consituents: dairy, milk, cheese, yoghurt, probiotics, whey protein, alpha lactalbumin, calcium, B-12, bioactive peptides and colostrinin (CLN). These search terms for dairy products were combined with the following search terms related to cognition and health: cognition, cognitive decline, dementia, Alzheimer's disease, metabolic syndrome, diabetes, insulin resistance and glucose regulation. Concerns regarding SFA and other fatty acids found in dairy products are also reviewed in relation to different forms of dairy products. The review also considers recent evidence for positive neurocognitive effects associated with bioactive peptides, CLN and proline-rich polypeptides, α-lactalbumin, vitamin B12, calcium and probiotics. Future directions for the extraction and purification of beneficial constituents are also discussed. It is concluded that low-fat dairy products, when consumed regularly as part of a balanced diet, may have a number of beneficial outcomes for neurocognitive health during ageing.

Rational: Previous research has suggested that long-term verbal declarative memory is particularly sensitive to enhancement by glucose loading; however, investigation of glucose effects on certain memory domains has hitherto been neglected. Therefore, domain specificity of glucose effects merits further elucidation. Objectives: The aim of the present research was to provide a more comprehensive investigation of the possible effects of glucose administration on different aspects of memory by 1) contrasting the effect of glucose administration on different memory domains (implicit/explicit memory; verbal/non-verbal memory, and recognition/familiarity processes), 2) investigating whether potential effects on memory domains differ depending on the dose of glucose administered (25 g versus 60 g), 3) exploring the duration of the glucose facilitation effect (assessment of memory performance 35 min and 1 week after encoding). Methods: A double-blind between-subjects design was used to test the effects of administration of 25 and 60 g glucose on memory performance. Results: Implicit memory was improved following administration of 60 g of glucose. Glucose supplementation failed to improve face recognition performance but significantly improved performance of word recall and recognition following administration of 60 g of glucose. However, effects were not maintained 1 week following encoding. Conclusions: Improved implicit memory performance following glucose administration has not been reported before. Furthermore, the current data tentatively suggest that level of processing may determine the required glucose dosage to demonstrate memory improvement and that higher dosages may be able to exert effects on memory pertaining to both hippocampal and non-hippocampal brain regions. © 2010 Springer-Verlag.

The COVID-19 lockdowns saw many individuals lose income, experience distress and increase intake of foods that would typically be considered less ‘healthy’ (more processed and less fresh produce). Establishing whether there are direct and indirect links between these variables would be of benefit in preparing for similar future events but also has implications for the current global financial climate, where many are experiencing relative decreases in income. Adults in two locations (UK and Australia) (N = 917) completed online questionnaires to explore the impact of the first COVID-19 lockdown on their change in income, emotional wellbeing (depression, anxiety, stress, loneliness), resilience and diet quality. A structural equation model revealed that income loss was indirectly associated with diet quality via distress. As such, the greater the loss of income experienced, the more distress reported; distress was then directly associated with a less nutritious diet. This pattern of results existed when data from both countries were combined but also when they were modelled individually. Our findings indicate that where individuals experience a sudden reduction of income there are likely to be negative consequences for both mental and physical health. It is plausible that these findings would extend to other circumstances in which sudden loss of income may be experienced such as reductions in state social care, rising inflation and interest rates and sudden increases to the general cost of living.

There are surprisingly few randomised, controlled trials into the effects of dietary change on mood and cognition in healthy individuals. Here we examined the effects of 10 days of changing to a nutrient-rich diet on mood and cognitive performance. Young female adults (N = 25) were randomised to a diet change (DC), or a no change (NC) control group. Those in the DC condition adhered to the nutrient-dense Mediterranean diet. Mood and cognitive performance were assessed at baseline and on day 10. Compared with the NC group, the DC group showed significant improvements in self-rated vigour, alertness and contentment. Changes in cognitive tasks were somewhat inconsistent. These preliminary findings require verification in larger trials but suggest that appropriate dietary change may benefit mood and some aspects of cognitive performance in healthy adults. © 2010.

There is growing evidence that dysbiosis of the gut microbiota is associated with the pathogenesis of both intestinal and extra-intestinal disorders. Intestinal disorders include inflammatory bowel disease, irritable bowel syndrome (IBS), and coeliac disease, while extra-intestinal disorders include allergy, asthma, metabolic syndrome, cardiovascular disease, and obesity.

Many people take nutraceuticals and supplements in the belief that they improve alertness or offset cognitive decline. Over the past decade or so there has been a large increase in the amount of research examining the links between diet, nutraceuticals and psychological function. This has revealed cognitive benefits from a number of sources. For example glucose administration improves cognitive functioning, and the mechanisms underlying this effect are increasingly understood. The glycaemic index (GI) of a food can also influence mental performance. There is also good evidence that certain dietary supplements have cognition-enhancing properties. These include endogenous substances which support neural structure and function (amino acids and polyunsaturated fatty acids). Other substances which improve cognitive function appear to do so by increasing energy availability to the brain either directly (e.g. creatine) or via improving cardiovascular functioning (e.g. CoQ10). Additionally certain herbal extracts can improve mood and cognitive function (in this chapter we use sage and lemon balm as examples). These effects are probably mediated by multiple actions including direct neurotransmitter modulation. Interestingly in the case of herbs, the behavioural effects are often in keeping with their usage in traditional medicine systems. There are numerous challenges in understanding the effects of nutraceuticals on cognition. As well as the issue of standardisation, there is the problem of understanding the mechanisms and underlying effects which involve multiple processes. These challenges are increasingly being met by new technologies which enhance our understanding of brain functioning.

The gut microbiota plays an important role in the maintenance of health and well-being throughout the life course but little is known about the impact of these changes on the balance of the microbiota and the well-being of women during their midlife transitional phase. In this exploratory, randomized, double-blind, placebo-controlled study, women (45 to 65 years old) received either a daily dose of probiotics or placebo for 4-months. Measurements of overall well-being included anxiety, depression, quality of life and sleep quality, gastrointestinal discomfort and changes to the fecal microbiota composition(ClinicalTrials.gov: NCT06507111). The women in the probiotic group showed a 40% reduction in anxiety, an 18.5% improvement in quality of life and indications of improved sleep, resulting in a significant 17.5% improvement in overall well-being compared to those in the placebo. Incidence rates of indigestion and stomach pains were reduced and Blautia sp. KLE 1732 was less abundant in the probotic group at the end of the study. Daily probiotic supplementation may support the well-being of women in their 40s − 60s.