Effect of oral γ-aminobutyric acid (GABA) administration on sleep and its absorption in humans

Sleep-enhancing activity of fermented pea protein hydrolysate with enhanced GABA content by Lactobacillus brevis SYLB 0016 fermentation

BACKGROUND

Sleep is essential for overall health and wellbeing. This study investigated the sleep-promoting effects of fermented pea protein hydrolysate (PPF) with increased gamma-aminobutyric acid (GABA) content produced by Lactobacillus brevis SYLB 0016. The effects of PPF on sleep duration and structure were assessed in pentobarbital-induced ICR mice and Sprague Dawley (SD) rats using electroencephalogram (EEG) analysis.

RESULTS

Hydrolysis of pea protein with Alcalase, Protana Prime, and Protana UBoost increased the amino nitrogen content, degree of hydrolysis and glutamate content to 160.51 mmol L-1. Fermentation by Lactobacillus brevis SYLB 0016 increased the GABA content from 3.16 to 90.35 mmol L-1. PPF significantly increased sleep duration (56.3 min) compared to the normal control (30.6 min) in pentobarbital-induced sleep tests. Non-rapid eye movement (NREM) sleep time increased with a significant rise in δ-waves activity following administration of 150 mg kg-1 of PPF. In caffeine-induced insomnia, both low- and high-dose PPF significantly increased sleep duration. Three weeks of oral PPF administration elevated GABAA and GABAB receptor expression, with GABAA receptor protein levels showing a significant change. Co-administration of flumazenil with PPF reduced sleep time, indicating the involvement of the GABAA receptor benzodiazepine site in PPF's sleep-enhancing effects.

CONCLUSION

In conclusion, PPF with enhanced GABA content improves NREM sleep by increasing δ waves activity. As a hypoallergenic compound, PPF holds potential as a supplement to ameliorate sleep disorders. © 2025 Society of Chemical Industry.

Short-term γ-aminobutyric acid antagonist treatment improves long-term sleep quality, memory, and decision-making in a Down syndrome mouse model

Down syndrome (DS) is a common genetic condition affecting people worldwide. It involves cognitive disabilities for which there are no drug therapies. The Ts65Dn mouse model of DS shows cognitive impairment due to a reduction in neuron number and connectivity as well as excessive neuronal activity, as γ-aminobutyric acid (GABA) antagonist treatment restores memory in these mice. Our study showed the effects of GABA antagonist treatment on sleep and decision-making in Ts65Dn mice. We administered a daily, low oral dose of pentylenetetrazol (PTZ) in milk to Ts65Dn mice for 17 days. Decision-making was tested with and without PTZ treatment. Short and long-term memories were tested before, immediately after, and 1 month following PTZ treatment. Electro-encephalography was also recorded at these three time points to study the effect of the treatment on sleep. We showed that PTZ treatment improved long-term recognition, but not short term memory and led to more Ts65Dn mice showing safer decision-making behavior. PTZ treatment showed a moderate and only global beneficial effect on sleep by decreasing the global amount of wake and increasing non-rapid eye movement sleep in the Ts65Dn mice, which may explain the observed cognitive improvements. These results bring new knowledge on the role of GABA in sleep, memory consolidation, and decision-making abilities in DS.

Neurotransmitter modulation of sleep-wake States: From molecular mechanisms to therapeutic potential

Sleep is one of the most fundamental physiological activities in humans and animals, and a normal sleep cycle is crucial for maintaining overall health. However, sleep disorders are increasingly becoming a major mental health issue affecting individuals and society, as well as a contributing factor to the onset of other diseases. Consequently, the development of novel therapeutic strategies for sleep disorders has emerged as a significant scientific challenge garnering widespread attention. Based on current research findings, focusing on neurotransmitters remains a promising approach for developing effective treatments. Neurotransmitters play a central role in regulating the sleep-wake cycle by precisely modulating the activity states of different brain regions. This review aims to elucidate the neural mechanisms underlying sleep initiation and function, thereby providing a comprehensive understanding of the complex nature of sleep as a physiological process. Furthermore, it seeks to uncover the potential pathological mechanisms of sleep disorders, offering a theoretical foundation and novel insights for precision medicine and drug development, ultimately reducing the negative impact of sleep disorders on individuals and society.

Effects of combined gamma aminobutyric acid supplementation and exercise training on the body composition of women: A randomized double-blind trial

BACKGROUND

Preclinical and clinical investigations have revealed the metabolic health benefits of gamma-aminobutyric acid (GABA) supplementation. Exercise training is widely acknowledged for its positive effects on the health of individuals with obesity.

OBJECTIVE

To investigate the effects of combined GABA supplementation and exercise training on the body composition, nutritional intake, physical performance, and serum biomarkers of women with obesity.

METHODS

Twenty-six women with obesity were investigated in this randomized, double-blind, placebo-controlled trial. They received daily GABA (200 mg) supplementation for 90 days alongside exercise training (3 days/week).

RESULTS

For intragroup comparisons hand grip improved in both groups (placebo, p = 0.00276; GABA, p = 0.00012), while sit-up performance increased only in the GABA group (p = 0.00664). Body mass index (p = 0.01273) and waist circumference (p = 0.01393) decreased in the GABA group. In the placebo group, body mass (p = 0.02956), fat-free mass (p = 0.00344), and basal metabolic rate (BMR) (p = 0.00386) decreased, while body fat increased (p = 0.02666). There were no differences in daily macronutrient intake, BMR, body mass, body fat, fat mass, fat-free mass, hip circumference, waist-hip ratio, blood pressure, heart rate, or serum levels of glucose, triglycerides, leptin, resistin, chemokine (C-C motif) ligand 2, chemokine ligand 16, and growth hormone between groups.

CONCLUSION

GABA supplementation combined with exercise training enhanced physical performance, accompanied by modest improvements in body composition, with no adverse effects on nutritional, physiological, or blood serum parameters.

STUDY REGISTRATION

https://ensaiosclinicos.gov.br/rg/RBR-8t7h259.

Modulation of GABAergic system as a therapeutic option in stroke

Stroke is one of the leading causes of death and permanent adult disability worldwide. Despite the improvements in reducing the rate and mortality, the societal burden and costs of treatment associated with stroke management are increasing. Most of the therapeutic approaches directly targeting ischemic injury have failed to reduce short- and long-term morbidity and mortality and more effective therapeutic strategies are still needed to promote post-stroke functional recovery. Decades of stroke research have been focused on hyperexcitability and glutamate-induced excitotoxicity in the acute phase of ischemia and their relation to motor deficits. Recent advances in understanding the pathophysiology of stroke have been made with several lines of evidence suggesting that changes in the neurotransmission of the major inhibitory system via γ-Aminobutyric acid (GABA) play a particularly important role in functional recovery and deserve further attention. The present review provides an overview of how GABAergic neurotransmission changes correlate with stroke recovery and outlines GABAergic system modulators with special emphasis on neurosteroids that have been shown to affect stroke pathogenesis or plasticity or to protect against cognitive decline. Supporting evidence from both animal and human clinical studies is presented and the potential for GABA signaling-targeted therapies for stroke is discussed to translate this concept to human neural repair therapies. Age and sex are considered crucial parameters related to the pathophysiology of stroke and important factors in the development of therapeutic pharmacological strategies. Future work is needed to deepen our knowledge of the neurochemical changes after stroke, extend the conceptual framework, and allow for the development of more effective interventions that include the modulation of the inhibitory system.

GABA and its receptors' mechanisms in the treatment of insomnia

Insomnia has now become a major health problem of global concern, with about 1/3 of the population suffering from sleep problems, a proportion that is still rising year by year. Most of the therapeutic drugs for insomnia currently used in clinical practice are not developed in a targeted manner, but are discovered by chance, and have unavoidable side effects such as addiction. Finding a safer and more effective therapeutic drug has become an urgent need for current research. Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system. It can ameliorate Insomnia, Alzheimer's disease, Parkinson's disease, Epilepsy, and other neurological disorders. Various mechanisms have been reported for GABA to ameliorate insomnia, such as GABAA receptor modulation, GABAB receptor modulation, inhibition of neuroinflammatory responses, repair of oxidative damage, and inter-regulation of the circadian rhythm hormone melatonin. GABA is a potential therapeutic target in the prevention and treatment of insomnia. This paper reviews mechanisms of GABA and its receptors in insomnia diseases and the potential of GABA analogs application and discusses the research progress of GABA as a promising therapeutic drug for insomnia diseases. This will help the development of novel targeted GABA-like drugs and provide new ideas and methods for the clinical treatment of insomnia.

Uncovering the effects and mechanisms of tea and its components on depression, anxiety, and sleep disorders: A comprehensive review

Depression, anxiety and sleep disorders are prevalent psychiatric conditions worldwide, significantly impacting the physical and mental well-being of individuals. The treatment of these conditions poses various challenges, including limited efficacy and potential side effects. Tea, a globally recognized healthful beverage, contains a variety of active compounds. Studies have shown that consuming tea or ingesting its certain active ingredients have a beneficial impact on the mental health issues mentioned above. While the effects of tea on physical health are well-documented, there remains a gap in our systematic understanding of its impact on mental health. This article offers a thorough overview of animal, clinical, and epidemiological studies examining tea and its components in the treatment of depression, anxiety, and sleep disorders, and summarizes the associated molecular mechanisms. The active ingredients in tea, including L-theanine, γ-aminobutyric acid (GABA), arginine, catechins, theaflavins, caffeine, theacrine, and several volatile compounds, may help improve depression, anxiety, and sleep disorders. The underlying molecular mechanisms involve the regulation of neurotransmitters, including monoamines, GABA, and brain-derived neurotrophic factor (BDNF), as well as the suppression of oxidative stress and inflammation. Additionally, these ingredients may influence the microbiota-gut-brain (MGB) axis and the hypothalamic-pituitary-adrenal (HPA) axis. This review provides valuable insights into the effects and mechanisms by which tea and its components regulate depression, anxiety, and sleep disorders, laying the groundwork for further research into relevant mechanisms and the development of tea-based mental health products.

Insomnia and intestinal microbiota: a narrative review

PURPOSE

The intestinal microbiota and insomnia interact through the microbiota-gut-brain axis. The purpose of this review is to summarize and analyze the changes of intestinal microbiota in insomnia, the interaction mechanisms between intestinal microbiota and insomnia and the treatment methods based on the role of microbiota regulation in insomnia, in order to reveal the feasibility of artificial intervention of intestinal microbiota to improve insomnia.

METHODS

Pubmed/ Embase were searched through March 2024 to explore the relevant studies, which included the gut microbiota characteristics of insomnia patients, the mechanisms of interaction between insomnia and gut microbiota, and the relationship between gut microbiota and insomnia treatment.

RESULTS

Numerous studies implicated insomnia could induce intestinal microbiota disorder by activating the immune response, the hypothalamic-pituitary-adrenal axis, the neuroendocrine system, and affecting bacterial metabolites, resulting in intestinal ecological imbalance, intestinal barrier destruction and increased permeability. The intestinal microbiota exerted an influence on the central nervous system through its interactions with intestinal neurons, releasing neurotransmitters and inflammatory factors, which in turn, can exacerbate symptoms of insomnia. Artificial interventions of gut microbiota included probiotics, traditional Chinese medicine, fecal microbiota transplantation, diet and exercise, whose main pathway of action is to improve sleep by affecting the release of neurotransmitters and gut microbial metabolites.

CONCLUSION

There is an interaction between insomnia and gut microbiota, and it is feasible to diagnose and treat insomnia by focusing on changes in the gut microbiota of patients with insomnia. Large cross-sectional studies and fecal transplant microbiota studies are still needed in the future to validate its safety and efficacy.

Eucalyptus essential oil exerted a sedative-hypnotic effect by influencing brain neurotransmitters and gut microbes via the gut microbiota-brain axis

Sleep disorders are becoming more and more common, leading to many health problems. However, most of current available medications to treat sleep disorders are addictive and even impair cognitive abilities. Therefore, it is important to find a natural and safe alternative to treat sleep disorders. In this study, twenty-four 8-week-old male ICR mice (25 ± 2 g) were equally divided into three groups: the control group (gavage of 0.9% saline), the eucalyptus essential oil (EEO) group (10 mg/kg B.W.), and the diazepam group (1 mg/kg B.W.). Firstly, open field test and sleep induction test were used to determine the sedative-hypnotic effect of EEO. Secondly, the effect of EEO on neurotransmitters in the mice brain was determined. Finally, based on the gut microbiota-brain axis (GMBA), the effect of EEO on the intestinal flora of mice was explored. It was found that EEO significantly reduce the activity and prolong the sleep duration of mice, exhibiting a good sedative-hypnotic effect. In the brain, EEO could increase the levels of sleep-promoting neurotransmitters, such as glutamine, Gamma-aminobutyric acid (GABA), glycine, tryptophan, N-acetylserotonin, and 5-hydroxyindoleacetic acid (5-HIAA). In the intestine, EEO was found to increase the diversity of gut microbes, the abundance of short chain fatty acid (SCFA) producing flora, and the abundance of functional flora synthesizing GABA and glycine neurotransmitters. These studies suggested that EEO exerted a sedative-hypnotic effect by acting on gut microbes and neurotransmitters in the brain. EEO has the potential to become a natural and safe alternative to traditional hypnotic sedative drugs.

Gut microbiota: a potential influencer of insomnia occurring after COVID-19 infection

The prevalence of insomnia has increased in recent years, significantly affecting the lives of many individuals. Coronavirus disease 2019 (COVID-19) infection has been found to have a substantial impact on the human gut microbiota (GM). Clinical studies have shown that the high prevalence, prolonged duration, and refractory treatment of insomnia symptoms following the COVID-19 pandemic may be related to the effect of COVID-19 infection on the GM. Therefore, the GM may be a potential target for the treatment of insomnia following COVID-19 infection. However, relevant studies have not been well-documented, and the GM has not been sufficiently analyzed in the context of insomnia treatment. Herein, we review the interaction between sleep and the GM, summarize the characteristics of COVID-19-induced abnormal changes in the GM and metabolites in patients with insomnia, and discuss potential mechanisms, including metabolic, immune, and neural pathways, by which these abnormal changes in the GM cause insomnia as well as the factors affecting the GM. Finally, we discuss the prospect of modulating the host GM community for the effective treatment of insomnia after COVID-19 infection and the need for further clinical studies.

Oncogenic fatty acid oxidation senses circadian disruption in sleep-deficiency-enhanced tumorigenesis

Circadian disruption predicts poor cancer prognosis, yet how circadian disruption is sensed in sleep-deficiency (SD)-enhanced tumorigenesis remains obscure. Here, we show fatty acid oxidation (FAO) as a circadian sensor relaying from clock disruption to oncogenic metabolic signal in SD-enhanced lung tumorigenesis. Both unbiased transcriptomic and metabolomic analyses reveal that FAO senses SD-induced circadian disruption, as illustrated by continuously increased palmitoyl-coenzyme A (PA-CoA) catalyzed by long-chain fatty acyl-CoA synthetase 1 (ACSL1). Mechanistically, SD-dysregulated CLOCK hypertransactivates ACSL1 to produce PA-CoA, which facilitates CLOCK-Cys194 S-palmitoylation in a ZDHHC5-dependent manner. This positive transcription-palmitoylation feedback loop prevents ubiquitin-proteasomal degradation of CLOCK, causing FAO-sensed circadian disruption to maintain SD-enhanced cancer stemness. Intriguingly, timed β-endorphin resets rhythmic Clock and Acsl1 expression to alleviate SD-enhanced tumorigenesis. Sleep quality and serum β-endorphin are negatively associated with both cancer development and CLOCK/ACSL1 expression in patients with cancer, suggesting dawn-supplemented β-endorphin as a potential chronotherapeutic strategy for SD-related cancer.

The role of the GABAergic system on insomnia

Sleep is an essential activity for the survival of mammals. Good sleep quality helps promote the performance of daily functions. In contrast, insufficient sleep reduces the efficiency of daily activities, causes various chronic diseases like Alzheimer's disease, and increases the risk of having accidents. The GABAergic system is the primary inhibitory neurotransmitter system in the central nervous system. It transits the gamma-aminobutyric acid (GABA) neurotransmitter via GABAA and GABAB receptors to counterbalance excitatory neurotransmitters, such as glutamate, noradrenaline, serotonin, acetylcholine, orexin, and dopamine, which release and increase arousal activities during sleep. Several studies emphasized that dysfunction of the GABAergic system is related to insomnia, the most prevalent sleep-related disorder. The GABAergic system comprises the GABA neurotransmitter, GABA receptors, GABA synthesis, and degradation. Many studies have demonstrated that GABA levels correlate with sleep quality, suggesting that modulating the GABAergic system may be a promising therapeutic approach for insomnia. In this article, we highlight the significance of sleep, the classification and pathology of insomnia, and the impact of the GABAergic system changes on sleep. In addition, we also review the medications that target the GABAergic systems for insomnia, including benzodiazepines (BZDs), non-BZDs, barbiturates, GABA supplements, and Chinese herbal medicines.

UPLC-ESI-MS/MS-based widely targeted metabolomics reveals differences in metabolite composition among four Ganoderma species

The Chinese name "Lingzhi" refers to Ganoderma genus, which are increasingly used in the food and medical industries. Ganoderma species are often used interchangeably since the differences in their composition are not known. To find compositional metabolite differences among Ganoderma species, we conducted a widely targeted metabolomics analysis of four commonly used edible and medicinal Ganoderma species based on ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry. Through pairwise comparisons, we identified 575-764 significant differential metabolites among the species, most of which exhibited large fold differences. We screened and analyzed the composition and functionality of the advantageous metabolites in each species. Ganoderma lingzhi advantageous metabolites were mostly related to amino acids and derivatives, as well as terpenes, G. sinense to terpenes, and G. leucocontextum and G. tsugae to nucleotides and derivatives, alkaloids, and lipids. Network pharmacological analysis showed that SRC, GAPDH, TNF, and AKT1 were the key targets of high-degree advantage metabolites among the four Ganoderma species. Analysis of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes demonstrated that the advantage metabolites in the four Ganoderma species may regulate and participate in signaling pathways associated with diverse cancers, Alzheimer's disease, and diabetes. Our findings contribute to more targeted development of Ganoderma products in the food and medical industries.

Terpenoids derived from Semen Ziziphi Spinosae oil enhance sleep by modulating neurotransmitter signaling in mice

Semen Ziziphi Spinosae oil (SZSO) is a natural vegetable oil extracted from Semen Ziziphi Spinosae, a traditional Chinese medicine renowned for its sleep-promoting properties, while the mechanisms are still unclear. Our findings revealed that the terpenoids present in SZSO (T-SZSO) were identified as the active components responsible for promoting sleep. Network pharmacological analysis suggested that T-SZSO targeted different sleep-aid pathways to varying degrees and exhibited potential for preventing central nervous system diseases. Notably, lupeol and betulinicaldehyde exhibited more pronounced effects. Additionally, T-SZSO significantly elevated serotonin levels, enhanced gamma-aminobutyric acid (GABA) synthesis, promoted GABA A receptor expression, and decreased glutamate and norepinephrine expression levels. Moreover, T-SZSO was found to downregulate IL-1β expression while upregulating superoxide dismutase and inducible nitric oxide synthase levels. In conclusion, this study presents the first investigation into the pharmacological basis of SZSO in promoting sleep and highlights the potential of nature food in improving suboptimal health conditions.

Sleep disorders cause Parkinson's disease or the reverse is true: Good GABA good night

BACKGROUND

Parkinson's disease (PD) is a progressive neurodegenerative brain disease due to degeneration of dopaminergic neurons (DNs) presented with motor and non-motor symptoms. PD symptoms are developed in response to the disturbance of diverse neurotransmitters including γ-aminobutyric acid (GABA). GABA has a neuroprotective effect against PD neuropathology by protecting DNs in the substantia nigra pars compacta (SNpc). It has been shown that the degeneration of GABAergic neurons is linked with the degeneration of DNs and the progression of motor and non-motor PD symptoms. GABA neurotransmission is a necessary pathway for normal sleep patterns, thus deregulation of GABAergic neurotransmission in PD could be the potential cause of sleep disorders in PD.

AIM

Sleep disorders affect GABA neurotransmission leading to memory and cognitive dysfunction in PD. For example, insomnia and short sleep duration are associated with a reduction of brain GABA levels. Moreover, PD-related disorders including rigidity and nocturia influence sleep patterns leading to fragmented sleep which may also affect PD neuropathology. However, the mechanistic role of GABA in PD neuropathology regarding motor and non-motor symptoms is not fully elucidated. Therefore, this narrative review aims to clarify the mechanistic role of GABA in PD neuropathology mainly in sleep disorders, and how good GABA improves PD. In addition, this review of published articles tries to elucidate how sleep disorders such as insomnia and REM sleep behavior disorder (RBD) affect PD neuropathology and severity. The present review has many limitations including the paucity of prospective studies and most findings are taken from observational and preclinical studies. GABA involvement in the pathogenesis of PD has been recently discussed by recent studies. Therefore, future prospective studies regarding the use of GABA agonists in the management of PD are suggested to observe their distinct effects on motor and non-motor symptoms.

CONCLUSION

There is a bidirectional relationship between the pathogenesis of PD and sleep disorders which might be due to GABA deregulation.

Co-fermented milk beverage has better stability and contains more health-promoting amino acid metabolites than single-strain-fermented milk beverage over one-month storage

Few studies investigated the effects of co-fermentation with bifidobacteria on post-storage changes of probiotic fermented beverages (PFBs). Thus, this study compared the post-storage changes in physicochemical index and metabolomes of PFBs produced singly by Lacticaseibacillus paracasei PC-01 (PC-01) or in combination with Bifidobacterium adolescentis B8589 (B8589). No significant differences were observed in the pH, titratable acidity, and viable cell counts between the two PFBs over 30-day storage. However, adding B8589 not only increased the stability of PFB (based on evaluating differences in PFBs metabolomics), but also the contents of beneficial amino acid metabolites, including 4-hydroxystyrene, gamma-aminobutyric acid, N-acetyl-l-aspartic acid, d-alanyl-d-alanine, and l-malic acid, after storage. Our study showed that B8589 is preferred to single-strain fermentation by PC-01. This study supports the concept of using bifidobacteria as starter culture in PFB production.

Multidirectional associations between the gut microbiota and Parkinson's disease, updated information from the perspectives of humoral pathway, cellular immune pathway and neuronal pathway

The human gastrointestinal tract is inhabited by a diverse range of microorganisms, collectively known as the gut microbiota, which form a vast and complex ecosystem. It has been reported that the microbiota-gut-brain axis plays a crucial role in regulating host neuroprotective function. Studies have shown that patients with Parkinson's disease (PD) have dysbiosis of the gut microbiota, and experiments involving germ-free mice and fecal microbiota transplantation from PD patients have revealed the pathogenic role of the gut microbiota in PD. Interventions targeting the gut microbiota in PD, including the use of prebiotics, probiotics, and fecal microbiota transplantation, have also shown efficacy in treating PD. However, the causal relationship between the gut microbiota and Parkinson's disease remains intricate. This study reviewed the association between the microbiota-gut-brain axis and PD from the perspectives of humoral pathway, cellular immune pathway and neuronal pathway. We found that the interactions among gut microbiota and PD are very complex, which should be "multidirectional", rather than conventionally regarded "bidirectional". To realize application of the gut microbiota-related mechanisms in the clinical setting, we propose several problems which should be addressed in the future study.

Multi-effective components and their target mechanism of Ziziphi Spinosae Semen in the treatment of insomnia

Insomnia is a common and refractory disease. Since more than 2000 years ago, people have been using Ziziphi Spinosae Semen (ZSS). However, there are lack of molecular mechanisms of sleep promotion effects of ZSS. The purpose of this study is to clarify the active ingredients in ZSS that are used to treat insomnia. Using a method called cellular label-free integrative pharmacology (CLIP), we established five insomnia-related target models, including serotonin (5HT2A and 5HT1A), melatonin (MT1), dopamine (D2) and epinephrine (β2) receptors. The one-dimensional (1D) fractions of ZSS extract were prepared on a RZC18 column and assayed on five models. Subsequently, the active fraction was further analyzed, fractionated and quantified using a two-dimensional (2D) liquid phase method coupled with a charged aerosol detector (CAD), This CAD-coupled 2D-LC method requires micro-fractions from the 1D separation and thus it greatly saves sample amounts and corresponding preparation time, and quickly conduct activity screening. The composition of the active 2D fractions was then determined using three-dimensional (3D) HPLC-MS, and molecular docking was separately carried out for the described compounds on the targets for activity prediction. Seven compounds were predicted to be active on 5HT2A, and two compounds on D2. We experimentally verified the prediction and found that vitexin exhibited D2 agonistic activity, and nuciferine exhibited 5HT2A antagonistic activity. This study revealed the effective components and their targets of ZSS in the treatment of insomnia, also highlighted the potential of the CLIP technique and bioactivity guided multi-dimensional HPLC-MS in molecular mechanism elucidation for traditional Chinese medicines.

Exploring the Therapeutic Potential of Gamma-Aminobutyric Acid in Stress and Depressive Disorders through the Gut-Brain Axis

Research conducted on individuals with depression reveals that major depressive disorders (MDDs) coincide with diminished levels of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) in the brain, as well as modifications in the subunit composition of the primary receptors (GABAA receptors) responsible for mediating GABAergic inhibition. Furthermore, there is substantial evidence supporting the significant role of GABA in regulating stress within the brain, which is a pivotal vulnerability factor in mood disorders. GABA is readily available and approved as a food supplement in many countries. Although there is substantial evidence indicating that orally ingested GABA may affect GABA receptors in peripheral tissues, there is comparatively less evidence supporting its direct action within the brain. Emerging evidence highlights that oral GABA intake may exert beneficial effects on the brain and psyche through the gut-brain axis. While GABA enjoys wide consumer acceptance in Eastern Asian markets, with many consumers reporting favorable effects on stress regulation, mood, and sleep, rigorous independent research is still largely lacking. Basic research, coupled with initial clinical findings, makes GABA an intriguing neuro-nutritional compound deserving of clinical studies in individuals with depression and other psychological problems.

Bioactive Ingredients from Dairy-Based Lactic Acid Bacterial Fermentations for Functional Food Production and Their Health Effects

Lactic acid bacteria are traditionally applied in a variety of fermented food products, and they have the ability to produce a wide range of bioactive ingredients during fermentation, including vitamins, bacteriocins, bioactive peptides, and bioactive compounds. The bioactivity and health benefits associated with these ingredients have garnered interest in applications in the functional dairy market and have relevance both as components produced in situ and as functional additives. This review provides a brief description of the regulations regarding the functional food market in the European Union, as well as an overview of some of the functional dairy products currently available in the Irish and European markets. A better understanding of the production of these ingredients excreted by lactic acid bacteria can further drive the development and innovation of the continuously growing functional food market.

Association of plant-based diet index with sleep quality in middle-aged and older adults: The Healthy Dance Study

OBJECTIVES

To investigate the association between plant-based diet indices and sleep quality in Chinese middle-aged and older adults.

METHODS

The study included 2424 participants aged 45 years and older. Dietary data were collected using a semi-quantitative food frequency questionnaire, and sleep quality was assessed by the Pittsburgh Sleep Quality Index scale. Plant-based diet was categorized based on 3 indices (score range, 17-85) covering 17 food groups: the overall plant-based diet index, healthful plant-based diet index, and unhealthful plant-based diet index. The associations between these plant-based diet indices and sleep quality were examined using logistic and linear regression analyses.

RESULTS

After controlling for sociodemographic, lifestyle, and multiple disease-related factors, participants in the highest quartile of the healthful plant-based diet index had 0.55 higher odds of better sleep quality (95% CI: 0.42, 0.72; Ptrend< .001). In contrast, participants in the highest quartile of the unhealthful plant-based diet index had 2.03 higher odds of poor sleep quality (95% CI: 1.51, 2.72; Ptrend< .001). In addition, plant-based diet index and healthful plant-based diet index were inversely associated with Pittsburgh Sleep Quality Index scores, while unhealthful plant-based diet index and Pittsburgh Sleep Quality Index scores were positively associated.

CONCLUSIONS

We found unhealthy plant-based diets are significantly associated with poor sleep quality. Adherence to overall plant-based diets, especially healthy plant-based diets, was positively associated with optimal sleep quality.

Overview of the impact of sleep monitoring on optimal performance, immune system function and injury risk reduction in athletes: A narrative review

Sleep is essential for a range of physiological and mental functions in professional athletes. There is proof that athletes may experience lower quality and quantity of sleep. While adequate sleep has been shown to have restorative effects on the immune system and endocrine system, facilitate nervous system recovery and the metabolic cost of wakefulness, and play a significant role in learning, memory, and synaptic plasticity, which can affect sports recovery, injury risk reduction, and performance. Sports performance may suffer significantly from a lack of sleep, especially under maximal and long-term exercise. Due to the potential harm, these factors may do to an athlete's endocrine, metabolic, and nutritional health, sports performance is impacted by reduced sleep quality or quantity. There are several neurotransmitters associated with the sleep-wake cycle that have been discovered. They comprise cholinergic hormone, orexin, melanin, galanin, serotonin, gamma-aminobutyric acid, histamine, and serotonin. Therefore, dietary modifications that affect the neurotransmitters in the brain also may affect sleep; particularly for athletes who require more physical and psychological recovery owing to the tremendous physiological and psychological demands placed on them during training and performance. This review explores the variables that influence the quantity and quality of sleep-in populations of athletes and assesses their possible effects. In addition, several recommendations for improving sleep are presented. Even though there has been much research on variables that impact sleep, future studies may highlight the significance of these aspects for athletes.

Production of GABA in milk fermented by Bifidobacterium adolescentis strains selected on the bases of their technological and gastrointestinal performance

There is an increasing interest in producing foods enriched in gamma-aminobutyric acid (GABA), due to their purported health promoting attributes. GABA is the main inhibitor neurotransmitter of the central nervous system, and several microbial species are capable to produce it through decarboxylation of glutamate. Among them, several lactic acid bacteria species have been previously investigated as an appealing alternative to produce GABA enriched foods via microbial fermentation. In this work we report for the first time an investigation into the possibility of utilizing high GABA-producing Bifidobacterium adolescentis strains as a mean to produce fermented probiotic milks naturally enriched in GABA. To this end, in silico and in vitro analyses were conducted in a collection of GABA-producing B. adolescentis strains, with the main goal to scrutinize their metabolic and safety traits, including antibiotic resistance patterns, as well as their technological robustness and performance to survive a simulated gastrointestinal passage. One of the strains, IPLA60004, exhibited better survival to lyophilization and cold storage (for up to 4 weeks at 4 °C), as well as survival to gastrointestinal passage, as compared to the other strains under investigation. Besides, the elaboration of milk drinks fermented with this strain, yielded products with the highest GABA concentration and viable bifidobacterial cell counts, achieving conversion rates of the precursor, monosodium glutamate (GMS), up to 70 %. To our knowledge, this is the first report on the elaboration of GABA enriched milks through fermentation with B. adolescentis.

Evaluation of the Antihypertensive Activity of Eggplant Acetylcholine and γ-Aminobutyric Acid in Spontaneously Hypertensive Rats

Daily consumption of eggplant powder containing 2.3 mg acetylcholine (ACh) is known to alleviate hypertension and improve mental status. However, eggplant powder used in clinical trials also contains the antihypertensive compound γ-aminobutyric acid (GABA). Although our previous study indicated that the main antihypertensive compound in eggplant is ACh, given that GABA amounts in eggplant do not reach the effective dosage, the effects of GABA on the antihypertensive effect of eggplant remain unclear. It is necessary to establish whether there is a synergistic effect between GABA and ACh and whether GABA in eggplant exerts antihypertensive effects. Consequently, here we sought to evaluate the effects of GABA on the antihypertensive effects of eggplant. We used a probability sum (q) test to investigate the combined effects of ACh and GABA and prepared eggplant powder with very low ACh content for oral administration in animals. ACh and GABA exhibited additive effects but the GABA content in eggplants was not sufficient to promote a hypotensive effect. In conclusion, ACh is the main component associated with the antihypertensive effects of eggplant but GABA within eggplants has a minimal effect in this regard. Thus, compared with GABA, ACh could be a more effective functional food constituent for lowering blood pressure.

Disturbed rhythmicity of intestinal hydrogen peroxide alters gut microbial oscillations in BMAL1-deficient monkeys

Circadian oscillation of gut microbiota exerts significant influence on host physiology, but the host factors that sustain microbial oscillations are rarely reported. We compared the gut microbiome and metabolome of wild-type and BMAL1-deficient cynomolgus monkeys during a diurnal cycle by performing 16S rRNA sequencing and untargeted fecal metabolomics and uncovered the influence of intestinal H₂O₂ on microbial compositions. Ablation of BMAL1 induced expansion of Bacteroidota at midnight and altered microbial oscillations. Some important fecal metabolites changed significantly, and we investigated their correlations with microbes. Further analyses revealed that disturbed rhythmicity of NOX1-derived intestinal H₂O₂ was responsible for the altered microbial oscillations in BMAL1-deficient monkeys. Mechanistic studies showed that BMAL1 transactivated NOX1 via binding to the E1-E2 site in its promoter. Notably, BMAL1-dependent activation of NOX1 was conserved in cynomolgus monkeys and humans. Our study demonstrates the importance of intestine clock-controlled H₂O₂ rhythmicity on the rhythmic oscillation of gut microbiota.

Complementary and Integrative Health Interventions for Insomnia in Veterans and Military Populations

Insomnia can be a serious problem diminishing quality of life for Veterans and military populations with and without posttraumatic stress disorder (PTSD). Sleep disturbances are one of the symptoms of PTSD but even after evidence-based PTSD treatments, insomnia symptoms often remain. The primary approaches for treating insomnia are cognitive behavioral therapy for insomnia (CBT-I) and pharmacotherapy. However, each of these treatments has drawbacks. Complementary and Integrative Health (CIH) approaches such as mindfulness meditation, mantram meditation, yoga, and tai chi may provide alternative treatments for insomnia in military populations. This paper provides a brief review of studies on CIH interventions for sleep disturbances in Veterans. It also proposes possible mechanisms by which CIH practices may be effective, including increasing hippocampal volume and gamma-aminobutyric acid acid (GABA). Finally, the acceptability of CIH approaches among Veterans is discussed.

Dietary supplements in neurological diseases and brain aging

A healthy diet shapes a healthy mind. Diet quality has a strong association with brain health. Diet influences the onset and consequences of neurological diseases, and dietary factors may influence mental health at individual and population level. The link between unhealthy diet, impaired cognitive function and neurodegenerative diseases indicates that adopting a healthy diet would ultimately afford prevention and management of neurological diseases and brain aging. Neurodegenerative diseases are of multifactorial origin and result in progressive loss of neuronal function in the brain, leading to cognitive impairment and motoneuron disorders. The so-called Mediterranean diet (MedDiet) with its healthy ingredients rich in antioxidant, anti-inflammatory, immune, neuroprotective, antidepressant, antistress and senolytic activity plays an essential role in the prevention and management of neurological diseases and inhibits cognitive decline in neurodegenerative diseases such as Alzheimer's, Parkinson's and Huntington's diseases. The MedDiet also modulates the gut-brain axis by promoting a diversity of gut microbiota. In view of the importance of diet in neurological diseases management, this review focuses on the dietary components, natural compounds and medicinal plants that have proven beneficial in neurological diseases and for brain health. Among them, polyphenols, omega-3 fatty acids, B vitamins and several ayurvedic herbs have promising beneficial effects.

The Effect of Dracocephalum Extract on Sleep Quality in Post-Menopausal Women: A Randomized Placebo-Controlled Trial

Objective: Sleep disturbance is one of the most prevalent problems in post-menopausal females. The current research intended to evaluate the effects of Dracocephalum on sleep disorder in post-menopausal females. Method : The current study is a randomized, double-blind controlled trial, in which 110 post-menopausal women were randomly allocated to Dracocephalum or placebo groups. The intervention group took Dracocephalum capsules containing 250 mg Dracocephalum extract twice daily for one month. While, the placebo group took the same capsule containing 250 mg of starch twice daily for one month. Pittsburgh Sleep Quality Index was completed by the participants of both groups before and after the treatment and the data obtained were analyzed with Chi-square, paired and independent t-test in SPSS (version 20). Results: The mean score of sleep quality before and after the treatment was 12.69 ± 3.98 and 8.58 ± 1.97 in the treatment group, respectively. Also, the score of sleep quality in the placebo group was 13.48 ± 2.60 and 11.21 ± 2.74 at the beginning and end of the research, respectively. The symptoms of sleep disorder in the intervention group significantly improved after the treatment (P < 0.001), while this was not the case with the placebo group (P = 0.155). Besides, there was a significant difference between the two groups in the mean score of sleep quality after the treatment (P = 0.012). Conclusion: Dracocephalum extracts are effective in reducing symptoms of sleep disorders in post-menopausal women.

Dietary Gamma-Aminobutyric Acid (GABA) Induces Satiation by Enhancing the Postprandial Activation of Vagal Afferent Nerves

Gamma-aminobutyric acid (GABA) is present in the mammalian brain as the main inhibitory neurotransmitter and in foods. It is widely used as a supplement that regulates brain function through stress-reducing and sleep-enhancing effects. However, its underlying mechanisms remain poorly understood, as it is reportedly unable to cross the blood–brain barrier. Here, we explored whether a single peroral administration of GABA affects feeding behavior as an evaluation of brain function and the involvement of vagal afferent nerves. Peroral GABA at 20 and 200 mg/kg immediately before refeeding suppressed short-term food intake without aversive behaviors in mice. However, GABA administration 30 min before refeeding demonstrated no effects. A rise in circulating GABA concentrations by the peroral administration of 200 mg/kg GABA was similar to that by the intraperitoneal injection of 20 mg/kg GABA, which did not alter feeding. The feeding suppression by peroral GABA was blunted by the denervation of vagal afferents. Unexpectedly, peroral GABA alone did not alter vagal afferent activities histologically. The coadministration of a liquid diet and GABA potentiated the postprandial activation of vagal afferents, thereby enhancing postprandial satiation. In conclusion, dietary GABA activates vagal afferents in collaboration with meals or meal-evoked factors and regulates brain function including feeding behavior.

Recent advances in the utilization of tea active ingredients to regulate sleep through neuroendocrine pathway, immune system and intestinal microbiota

Sleep disorders have received widespread attention nowadays, which have been promoted by the accelerated pace of life, unhealthy diets and lack of exercise in modern society. The chemical medications to improve sleep has shown serious side effects and risks with high costs. Therefore, it is urgent to develop efficient nutraceuticals from natural sources to ensure sleep quality as a sustainable strategy. As the second most consumed beverage worldwide, the health-promoting effects of tea have long been widely recognized. However, the modulatory effect of teas on sleep disorders has received much less attention. Tea contains various natural sleep-modulating active ingredients such as L-theanine (LTA), caffeine, tea polyphenols (TPP), tea pigments, tea polysaccharides (TPS) and γ-aminobutyric acid (GABA). This review focuses on the potential influence and main regulating mechanisms of different tea active ingredients on sleep, including being absorbed by the small intestine and then cross the blood-brain barrier to act on neurons in the brain as neurotransmitters, manipulating the immune system and further affect sleep-wake cycle by regulating the levels of cytokines, and controlling the gut microbes to maintain the homeostasis of circadian rhythm. Current research progress and limitations are summarized and several future development directions are also proposed. This review hopes to provide new insights into the future elucidation of the sleep-regulating mechanisms of different teas and their natural active ingredients and the development of tea-based functional foods for alleviating sleep disorders. HighlightsNatural sleep-modulating active ingredients in tea have been summarized.Influences of drinking tea or tea active ingredients on sleep are reviewed.Three main regulating mechanisms of tea active ingredients on sleep are explained.The associations among nervous system, immune system and intestinal microbiota are investigated.The potential of developing delivery carriers for tea active ingredients is proposed.

Cell factory for γ-aminobutyric acid (GABA) production using Bifidobacterium adolescentis

Background

Bifidobacteria are gram-positive, probiotic, and generally regarded as safe bacteria. Techniques such as transformation, gene knockout, and heterologous gene expression have been established for Bifidobacterium, indicating that this bacterium can be used as a cell factory platform. However, there are limited previous reports in this field, likely because of factors such as the highly anaerobic nature of this bacterium. Bifidobacterium adolescentis is among the most oxygen-sensitive Bifidobacterium species. It shows strain-specific gamma-aminobutyric acid (GABA) production. GABA is a potent bioactive compound with numerous physiological and psychological functions. In this study, we investigated whether B. adolesentis could be used for mass production of GABA.

Results

The B. adolescentis 4–2 strain isolated from a healthy adult human produced approximately 14 mM GABA. It carried gadB and gadC, which encode glutamate decarboxylase and glutamate GABA antiporter, respectively. We constructed pKKT427::Pori-gadBC and pKKT427::Pgap-gadBC plasmids carrying gadBC driven by the original gadB (ori) and gap promoters, respectively. Recombinants of Bifidobacterium were then constructed. Two recombinants with high production abilities, monitored by two different promoters, were investigated. GABA production was improved by adjusting the fermentation parameters, including the substrate concentration, initial culture pH, and co-factor supplementation, using response surface methodology. The optimum initial cultivation pH varied when the promoter region was changed. The ori promoter was induced under acidic conditions (pH 5.2:4.4), whereas the constitutive gap promoter showed enhanced GABA production at pH 6.0. Fed-batch fermentation was used to validate the optimum fermentation parameters, in which approximately 415 mM GABA was produced. The conversion ratio of glutamate to GABA was 92–100%.

Conclusion

We report high GABA production in recombinant B. adolescentis. This study provides a foundation for using Bifidobacterium as a cell factory platform for industrial production of GABA.

Fate of Bioactive Compounds during Lactic Acid Fermentation of Fruits and Vegetables

Consumption of lactic acid fermented fruits and vegetables has been correlated with a series of health benefits. Some of them have been attributed to the probiotic potential of lactic acid microbiota, while others to its metabolic potential and the production of bioactive compounds. The factors that affect the latter have been in the epicenter of intensive research over the last decade. The production of bioactive peptides, vitamins (especially of the B-complex), gamma-aminobutyric acid, as well as phenolic and organosulfur compounds during lactic acid fermentation of fruits and vegetables has attracted specific attention. On the other hand, the production of biogenic amines has also been intensively studied due to the adverse health effects caused by their consumption. The data that are currently available indicate that the production of these compounds is a strain-dependent characteristic that may also be affected by the raw materials used as well as the fermentation conditions. The aim of the present review paper is to collect all data referring to the production of the aforementioned compounds and to present and discuss them in a concise and comprehensive way.

Perspective on the Formation, Analysis, and Health Effects of Neuroactive Compounds in Foods

Foods contain neuroactive compounds, such as γ-aminobutyric acid, serotonin, kynurenic acid, and catecholamines. Neuroactive compounds synthesized by humans have various behavioral and physiological roles. It is thus significant for future studies to investigate how diet-derived neuroactive compounds can impact human health and mood. In this perspective, we provide a background for the brief formation mechanisms of neuroactive compounds in plants and microorganisms, their concentrations in foods, and their potential health effects. Liquid chromatography approaches for the analysis of neuroactive compounds are highlighted, together with the extraction procedures. The possibilities for the design of novel foods containing neuroactive compounds are also discussed.

Cordyceps militaris: An Overview of Its Chemical Constituents in Relation to Biological Activity

Cordyceps spp. mushrooms have a long tradition of use as a natural raw material in Asian ethnomedicine because of their adaptogenic, tonic effects and their ability to reduce fatigue and stimulate the immune system in humans. This review aims to present the chemical composition and medicinal properties of Cordyceps militaris fruiting bodies and mycelium, as well as mycelium from in vitro cultures. The analytical results of the composition of C. militaris grown in culture media show the bioactive components such as cordycepin, polysaccharides, γ-aminobutyric acid (GABA), ergothioneine and others described in the review. To summarize, based on the presence of several bioactive compounds that contribute to biological activity, C. militaris mushrooms definitely deserve to be considered as functional foods and also have great potential for medicinal use. Recent scientific reports indicate the potential of cordycepin in antiviral activity, particularly against COVID-19.

Gamma-Aminobutyric Acid (GABA) Promotes Growth in Zebrafish Larvae by Inducing IGF-1 Expression via GABAA and GABAB Receptors

Insulin-like growth factor-1 (IGF-1) primarily increases the release of gamma-aminobutyric acid (GABA) in neurons; moreover, it is responsible for the promotion of longitudinal growth in children and adolescents. Therefore, in this study, we investigated whether exogenous GABA supplementation activates IGF-mediated growth performance. Zebrafish larvae treated with GABA at three days post fertilization (dpf) showed a significant increase in the total body length from 6 to 12 dpf through upregulation of growth-stimulating genes, including IGF-1, growth hormone-1 (GH-1), growth hormone receptor-1 (GHR-1), and cholecystokinin A (CCKA). In particular, at 9 dpf, GABA increased total body length from 3.60 ± 0.02 to 3.79 ± 0.03, 3.89 ± 0.02, and 3.92 ± 0.04 mm at concentrations of 6.25, 12.5, and 25 mM, and the effect of GABA at 25 mM was comparable to 4 mM β-glycerophosphate (GP)-treated larvae (3.98 ± 0.02 mm). Additionally, the highest concentration of GABA (50 mM) -induced death in 50% zebrafish larvae at 12 dpf. GABA also enhanced IGF-1 expression and secretion in preosteoblast MC3T3-E1 cells, concomitant with high levels of the IGF-1 receptor gene (IGF-1R). In zebrafish larvae, the GABA-induced growth rate was remarkably decreased in the presence of an IGF-1R inhibitor, picropodophyllin (PPP), which indicates that GABA-induced IGF-1 enhances growth rate via IGF-1R. Furthermore, we investigated the effect of GABA receptors on growth performance along with IGF-1 activation. Inhibitors of GABA_A and GABA_B receptors, namely bicuculline and CGP 46381, respectively, considerably inhibited GABA-induced growth rate in zebrafish larvae accompanied by a marked decrease in the expression of growth-stimulating genes, including IGF-1, GH-1, GHR-1, and CCKA, but not with an inhibitor of GABA_C receptor, TPMPA. Additionally, IGF-1 and IGF-1R expression was impaired in bicuculline and CGP 46381-treated MC3T3-E1 cells, but not in the cells treated with TPMPA. Furthermore, treatment with bicuculline and CGP 46381 significantly downregulated GABA-induced IGF-1 release in MC3T3-E1 cells. These data indicate that GABA stimulates IGF-1 release via GABA_A and GABA_B receptors and leads to growth promotion performance via IGF-1R.

Exosome-Mediated Activation of Neuronal Cells Triggered by γ-Aminobutyric Acid (GABA)

γ-Aminobutyric acid (GABA) is a potent bioactive amino acid, and several studies have shown that oral administration of GABA induces relaxation, improves sleep, and reduces psychological stress and fatigue. In a recent study, we reported that exosomes derived from GABA-treated intestinal cells serve as signal transducers that mediate brain–gut interactions. Therefore, the purpose of this study was to verify the functionality of GABA-derived exosomes and to examine the possibility of improving memory function following GABA administration. The results showed that exosomes derived from GABA-treated intestinal cells (Caco-2) activated neuronal cells (SH-SY5Y) by regulating genes related to neuronal cell functions. Furthermore, we found that exosomes derived from the serum of GABA-treated mice also activated SH-SY5Y cells, indicating that exosomes, which are capable of activating neuronal cells, circulate in the blood of mice orally administered GABA. Finally, we performed a microarray analysis of mRNA isolated from the hippocampus of mice that were orally administered GABA. The results revealed changes in the expression of genes related to brain function. Gene Set Enrichment Analysis (GSEA) showed that oral administration of GABA affected the expression of genes related to memory function in the hippocampus.

[Astenic disorders within the framework of post-covid syndrome]

The direct neurotropic and neurotoxic effect of the SARS-CoV-2 virus on the central nervous system, as well as the stressful effect of various factors of the COVID-19 pandemic, contribute to the development of the so-called post-COVID syndrome. The clinical picture of the syndrome includes asthenic, anxiety-asthenic, and depressive manifestations. When prescribing psychopharmacotherapy to patients who have undergone COVID-19, it is recommended to assess the potential benefits and risks in the aspect of using drugs not only with therapeutic antiasthenic and anxiolytic properties, but with minimally expressed undesirable effects and adverse drug interactions.

Nutritional Interventions to Improve Sleep in Team-Sport Athletes: A Narrative Review

Athletes often experience sleep disturbances and poor sleep as a consequence of extended travel, the timing of training and competition (i.e., early morning or evening), and muscle soreness. Nutrition plays a vital role in sports performance and recovery, and a variety of foods, beverages, and supplements purportedly have the capacity to improve sleep quality and quantity. Here, we review and discuss relevant studies regarding nutrition, foods, supplements, and beverages that may improve sleep quality and quantity. Our narrative review was supported by a semi-systematic approach to article searching, and specific inclusion and exclusion criteria, such that articles reviewed were relevant to athletes and sporting environments. Six databases—PubMed, Scopus, CINAHL, EMBASE, SPORTDiscus, and Google Scholar—were searched for initial studies of interest from inception to November 2020. Given the paucity of sleep nutrition research in the athlete population, we expanded our inclusion criteria to include studies that reported the outcomes of nutritional interventions to improve sleep in otherwise healthy adults. Carbohydrate ingestion to improve sleep parameters is inconclusive, although high glycemic index foods appear to have small benefits. Tart cherry juice can promote sleep quantity, herbal supplements can enhance sleep quality, while kiwifruit and protein interventions have been shown to improve both sleep quality and quantity. Nutritional interventions are an effective way to improve sleep quality and quantity, although further research is needed to determine the appropriate dose, source, and timing in relation to training, travel, and competition requirements.

Oral Administration of Armillaria mellea Mycelia Promotes Non-Rapid Eye Movement and Rapid Eye Movement Sleep in Rats

The present study aimed to explore whether water and ethanol extracts of Armillaria mellea mycelia produce sedative and hypnotic effects in rats. Male Sprague–Dawley rats were surgically implanted with two electroencephalogram electrodes on the skull and an electromyogram electrode on neck muscle to evaluate the alterations in rapid eye movement (REM) and non-REM (NREM) sleep after oral administration of the water and ethanol extracts. Following post-surgical recovery, thirty-six rats were randomly divided into four treatment groups and two control groups. They were treated orally with vehicle, 75 and 150 mg/kg doses of water and ethanolic extracts 15 min prior to the onset of dark (active) period. Electroencephalography results showed that the low dose of A. mellea mycelia water extract increased REM sleep time while the high dose enhanced both REM and NREM sleep times during the subsequent light (rest) period. On the other hand, although the low dose of A. mellea mycelia ethanolic extract did not alter both NREM sleep and REM sleep during the dark and light periods, the high dose increased both REM and NREM sleep during the light periods in naive rats. The HPLC-DAD analyses of both extracts allowed the identification of GABA and seven sesquiterpenoids. Based on these findings, the present study showed for the first time that water and ethanolic extracts of A. mellea mycelia, containing a source of biologically active compounds, could increase both NREM sleep and REM sleep during the rest period and may be useful for the treatment of insomnia.

Fermented Gamma Aminobutyric Acid Improves Sleep Behaviors in Fruit Flies and Rodent Models

The aim of this study was to investigate the effect of Lactobacillus brevis-fermented γ-aminobutyric acid (LB-GABA) on sleep behaviors in invertebrate and vertebrate models. In Drosophila melanogaster, LB-GABA-treated group showed an 8-9%-longer sleep duration than normal group did. LB-GABA-treated group also showed a 46.7% lower level of nighttime activity with a longer (11%) sleep duration under caffeine-induced arousal conditions. The LB-GABA-mediated inhibition of activity was confirmed as a reduction of total movement of flies using a video tracking system. In the pentobarbital-induced sleep test in mice, LB-GABA (100 mg/kg) shortened the time of onset of sleep by 32.2% and extended sleeping time by 59%. In addition, mRNA and protein level of GABAergic/Serotonergic neurotransmitters were upregulated following treatment with LB-GABA (2.0%). In particular, intestine- and brain-derived GABAA protein levels were increased by sevenfold and fivefold, respectively. The electroencephalography (EEG) analysis in rats showed that LB-GABA significantly increased non-rapid eye movement (NREM) (53%) with the increase in theta (θ, 59%) and delta (δ, 63%) waves, leading to longer sleep time (35%), under caffeine-induced insomnia conditions. LB-GABA showed a dose-dependent agonist activity on human GABAA receptor with a half-maximal effective concentration (EC50) of 3.44 µg/mL in human embryonic kidney 293 (HEK293) cells.

Advances in Nutritional Epigenetics-A Fresh Perspective for an Old Idea. Lessons Learned, Limitations, and Future Directions

Nutritional epigenetics is a rapidly expanding field of research, and the natural modulation of the genome is a non-invasive, sustainable, and personalized alternative to gene-editing for chronic disease management. Genetic differences and epigenetic inflexibility resulting in abnormal gene expression, differential or aberrant methylation patterns account for the vast majority of diseases. The expanding understanding of biological evolution and the environmental influence on epigenetics and natural selection requires relearning of once thought to be well-understood concepts. This research explores the potential for natural modulation by the less understood epigenetic modifications such as ubiquitination, nitrosylation, glycosylation, phosphorylation, and serotonylation concluding that the under-appreciated acetylation and mitochondrial dependant downstream epigenetic post-translational modifications may be the pinnacle of the epigenomic hierarchy, essential for optimal health, including sustainable cellular energy production. With an emphasis on lessons learned, this conceptional exploration provides a fresh perspective on methylation, demonstrating how increases in environmental methane drive an evolutionary down regulation of endogenous methyl groups synthesis and demonstrates how epigenetic mechanisms are cell-specific, making supplementation with methyl cofactors throughout differentiation unpredictable. Interference with the epigenomic hierarchy may result in epigenetic inflexibility, symptom relief and disease concomitantly and may be responsible for the increased incidence of neurological disease such as autism spectrum disorder.

Effects of Oral Gamma-Aminobutyric Acid (GABA) Administration on Stress and Sleep in Humans: A Systematic Review

Gamma-aminobutyric acid (GABA) is a non-proteinogenic amino acid and is the main inhibitory neurotransmitter in the mammalian brain. GABA's stress-reducing, and sleep enhancing effects have been established. However, although several human clinical trials have been conducted, results regarding the role of natural and/or biosynthetic oral GABA intake on stress and sleep are mixed. We performed a systematic review to examine whether natural and/or biosynthetic oral GABA intake has an effect on stress and sleep. We systematically searched on PubMed database for studies published up to February 2020 following PRISMA guidelines. Only placebo-controlled human trials that assessed stress, sleep, and related psychophysiological outcomes as a response to natural GABA (i.e., GABA that is present naturally in foods) or biosynthetic GABA (i.e., GABA that is produced via fermentation) intake were included. Fourteen studies met the criteria and were included in the systematic review. Although more studies are needed before any inferences can be made about the efficacy of oral GABA consumption on stress and sleep, results show that there is limited evidence for stress and very limited evidence for sleep benefits of oral GABA intake.

Challenges and Prospects of New Plant Breeding Techniques for GABA Improvement in Crops: Tomato as an Example

Over the last seven decades, γ-aminobutyric acid (GABA) has attracted great attention from scientists for its ubiquity in plants, animals and microorganisms and for its physiological implications as a signaling molecule involved in multiple pathways and processes. Recently, the food and pharmaceutical industries have also shown significantly increased interest in GABA, because of its great potential benefits for human health and the consumer demand for health-promoting functional compounds, resulting in the release of a plethora of GABA-enriched products. Nevertheless, many crop species accumulate appreciable GABA levels in their edible parts and could help to meet the daily recommended intake of GABA for promoting positive health effects. Therefore, plant breeders are devoting much effort into breeding elite varieties with improved GABA contents. In this regard, tomato (Solanum lycopersicum), the most produced and consumed vegetable worldwide and a fruit-bearing model crop, has received much consideration for its accumulation of remarkable GABA levels. Although many different strategies have been implemented, from classical crossbreeding to induced mutagenesis, new plant breeding techniques (NPBTs) have achieved the best GABA accumulation results in red ripe tomato fruits along with shedding light on GABA metabolism and gene functions. In this review, we summarize, analyze and compare all the studies that have substantially contributed to tomato GABA breeding with further discussion and proposals regarding the most recent NPBTs that could bring this process to the next level of precision and efficiency. This document also provides guidelines with which researchers of other crops might take advantage of the progress achieved in tomato for more efficient GABA breeding programs.

Neuroactive compounds in foods: Occurrence, mechanism and potential health effects

Neuroactive compounds are synthesized by certain plants and microorganisms by undertaking different tasks, especially as a stress response. Most common neuroactive compounds in foods are gamma-aminobutyric acid (GABA), serotonin, melatonin, kynurenine, kynurenic acid, dopamine, norepinephrine, histamine, tryptamine, tyramine and β-phenylethylamine. Fermented foods contain some of these compounds, which can affect human health and mood. Moreover, food processing such as roasting and malting alter amount and profile of neuroactive compounds in foods. In addition to plant-origin and microbially-formed neuroactive compounds in foods, these substances are also formed by gut microbiota, which is the most attractive subject to assess the interaction between gut microbiota and mental health. The discovery of microbiota-gut-brain axis calls for the investigation of the effects of diet on the formation of neuroactive compounds in the gut. Furthermore, probiotics and prebiotics are indispensable elements for the understanding of the food-mood relationship. The focus of this comprehensive review is to investigate the neuroactive compounds found naturally in foods or formed during fermentation. Their formation pathways in humans, plants and microorganisms, potential health effects, effects of diet on the formation of microbial metabolites including neuroactive compounds in the gut are discussed throughout this review. Furthermore, the importance of gut-brain axis, probiotics and prebiotics are discussed.