Fermented foods, the gut and mental health: a mechanistic overview with implications for depression and anxiety

Bidirectional Relationship Between Nutrition and Mental Health and Its Impact on the Health of Canadian Immigrants: An Integrative Review

Background: Immigration is a key factor contributing to population growth in Canada, a trend that is expected to continue. Immigrants generally arrive with better health than the Canadian-born population, but this advantage often diminishes over time, partially due to dietary acculturation. Emerging evidence points to a bidirectional link between nutrition and mental health. Objective: To explore the bidirectional relationship between nutrition and mental health and its impact on the health of Canadian immigrants, with a specific focus on immigrants' mental health and the healthy immigrant effect. Methods: For this integrative review, two comprehensive literature searches were conducted in the databases MEDLINE, CINAHL, Embase, PsycINFO, Scopus, and Web of Science from inception to July 2024. The review adhered to Whittemore and Knafl's integrative methodology, with the Mixed Methods Assessment Tool used to assess the quality of the studies. Results: A total of 42 and 34 scientific articles were included from the first and second literature searches, respectively. Four main themes emerged from the literature: (1) food insecurity and mental health, (2) obesity and mental health, (3) diet quality and mental health, and (4) the gut microbiome and mental health. These themes were explored in the context of Canadian immigrants' health. Conclusions: The health of immigrants to Canada is likely shaped by complex, bidirectional interactions among various determinants of health, influencing both physical and mental well-being. As newcomers are expected to form an increasing proportion of the Canadian population, further research is needed to understand how the interaction between nutrition and mental health can help promote and safeguard the health of Canadian immigrants.

Experimental model of primary intraocular lymphoma based on BALB/CaNn strain and A20 cells is optimal for investigational research

AIM

The purpose of this project was to compare the characteristics of two experimental murine models of primary intraocular lymphoma (PIOL) and determine which experimental model is most suitable for further investigational research to elucidate the pathophysiology of PIOL and to find new therapeutical strategies.

METHODS

In both experimental models PIOL was induced in immunocompetent mice with intravitreal injection of syngeneic B-cell lymphoma cell lines. Murine strain C3H/HeN and cell line 38C13 were used in the first model and BALB/CaNn mice and cell line A20 in the second model. During the experiments, thorough clinical evaluation (using photo documentation, ultrasonography, and MRI) and histological evaluation were performed.

RESULTS

In both models, the percentage of PIOL development was high, reaching nearly 80%. Disease progression was faster in C3H/HeN with exophthalmos occurring on average on day 10. Vitreous involvement was a predominant sign in the clinical presentation of this group. In BALB/CaNn mice exophthalmos occurred on average on day 22. The predominant clinical sign in the BALB/CaNn group was tumorous infiltration of the retina, optic disc, and tumorous retinal detachment.

CONCLUSION

Slower progression of the disease in BALB/CaNn mice, greater possibility to examine the retina due to mild vitreous involvement, and later occurrence of exophthalmos makes this strain more suitable for further investigational research.

The Bidirectional Relationship Between the Gut Microbiome and Mental Health: A Comprehensive Review

The gut microbiome plays a fundamental role in mental health, influencing mood, cognition, and emotional regulation through the gut-brain axis. This bidirectional communication system connects the gastrointestinal and CNS, facilitated by microbial metabolites, neurotransmitters, and immune interactions. Recent research highlights the association between gut dysbiosis and psychiatric disorders, including anxiety, depression, and stress-related conditions. Key findings indicate that altered microbial diversity, decreased short-chain fatty acid (SCFA) production, and increased neuroinflammation contribute to mental health disturbances. This paper explores the mechanism linking the gut microbiome to brain function, including microbial neurotransmitter synthesis, vagus nerve signaling, and hypothalamic-pituitary-adrenal (HPA) axis modulation. Additionally, it evaluates the potential of microbiome-targeted interventions, such as probiotics, prebiotics, dietary modifications, and fecal microbiota transplantation (FMT), in alleviating psychiatric symptoms. Microbiome sequencing and bioinformatics advances further support the development of personalized microbiome-based mental health interventions. Despite promising evidence, challenges such as inter-individual variability, methodological inconsistencies, and the need for longitudinal studies remain. Future research should focus on standardizing microbiome assessment techniques and optimizing therapeutic applications. Integrating precision psychiatry with microbiome-based diagnostics holds immense potential in transforming mental health treatment.

Associations between takeaway food consumption, physical activity levels, and their joint effect with comorbid depression and anxiety symptoms among Chinese university students

BACKGROUND

The prevalence of depression and anxiety symptoms, and their comorbid among Chinese university students is rising. Psychological symptoms are strongly associated with lifestyle choices, such as takeaway food consumption and physical activity. While the association between takeaway food consumption, physical activity level, and their joint effect on the psychological symptoms of university students are still unclear. In this study, we explore the associations between them.

METHODS

Using stratified cluster sampling, 14,340 students aged 18-22 from four provinces in China were selected as participants. A self-survey takeaway food consumption behavior questionnaire; the International Physical Activity Questionnaire Chinese Short Form; and the Depression, Anxiety, and Stress Scales-21 Short Version were used in this survey. Chi-square tests and binary logistic regression analyses were used to analyze the association.

RESULTS

The incidence rates of depression symptoms, anxiety symptoms, and CDAS were 26.26%, 34.58%, and 23.75%, respectively. Higher takeaway food consumption was positively associated with CDAS rates. Furthermore, compared with female students, the CDAS rates of male students were more likely to be influenced by different takeaway food consumption and physical activity. As for joint effect of takeaway food consumption and physical activity, overall, participants who engaged in light physical activity had a higher risk of CDAS with the increase in takeaway food consumption (OR = 1.279-2.661, 95% CI = 1.119-3.194, all p < 0.001). Moreover, participants with combination of moderate or vigorous physical activity and frequent takeaway food consumption (4-6 or ≥ 7 times/week) were more likely to suffer from CDAS (moderate: 4-6 times/week OR = 1.568, 95% CI: 1.206-2.039; ≥7 times/weeks: OR = 1.802, 95% CI: 1.202-2.700; vigorous: 4-6 times/week OR = 2.075, 95% CI: 1.623-2.653; ≥7 times/weeks: OR = 2.272, 95% CI: 1.567-3.295; all p < 0.05). In general, light to moderate physical activity levels and higher frequency of takeaway food consumption were associated with a higher risk of CDAS in male students than in female students.

CONCLUSION

High consumption of takeaway food and lower physical activity levels may be risk factors for depression and anxiety in university students. In general, the psychological symptoms of male students are more likely to be influenced by these factors than those of female students.

Gut Microbiota and Neurotransmitter Regulation: Functional Effects of Four Traditional Chinese Fermented Soybean (Sojae Semen Praeparatum)

This study aims to evaluate the potential disease prevention and treatment functions of four types of traditional Chinese fermented Sojae Semen Praeparatum (SSP) by analyzing their nutritional active components and their effects on the gut microbiota. Raw soybeans and the four SSPs were administered as dietary supplements to normal SD rats for 6 weeks. Fecal samples were collected at weeks 0, 2, and 6 to assess changes in the gut microbiota. Our results revealed that different fermentation methods resulted in variations in soybean isoflavone content. Fermented soybeans promoted the growth of beneficial microorganisms associated with short-chain fatty acid production in the gut microbiota, such as Christensenellaceae_R_7_group, compared to unfermented soybeans. Supplementation with SSPs fermented with different processes increased the diversity of the rat gut microbiota, except for the fermented group of qingwenjiedu decoction (QW). The dominant gut microbiota in the fermented group of Artemisia Annuae Herba and Mori Folium (QS) exhibited anti-inflammatory effects, while the dominant gut microbiota in the fermented group of Ephedrae Herba and Perillae Folium (MZ) showed antidepressant effects. In the neurotransmitter analysis, MZ reduced gamma-aminobutyric acid (GABA) levels, the fermented group without Chinese medicine (DD) decreased dopamine levels, and both QS and QW increased norepinephrine levels. Correlation analysis highlighted connections between gut microbiota, neurotransmitters, and chemical levels. The results indicate that SSPs may contribute uniquely to health by maintaining intestinal balance and improving neurological disorders while predicting a potential association between neurotransmitters and gut microbiota by correlation analysis.

The Interplay of Nutrition, the Gut Microbiota and Immunity and Its Contribution to Human Disease

Nutrition, the gut microbiota and immunity are all important factors in the maintenance of health. However, there is a growing realization of the complex interplay between these elements coalescing in a nutrition-gut microbiota-immunity axis. This regulatory axis is critical for health with disruption being implicated in a broad range of diseases, including autoimmune disorders, allergies and mental health disorders. This new perspective continues to underpin a growing number of innovative therapeutic strategies targeting different elements of this axis to treat relevant diseases. This review describes the inter-relationships between nutrition, the gut microbiota and immunity. It then details several human diseases where disruption of the nutrition-gut microbiota-immunity axis has been identified and presents examples of how the various elements may be targeted therapeutically as alternate treatment strategies for these diseases.

Role of the gut microbiome in psychological symptoms associated with inflammatory bowel diseases

The brain-gut axis constitutes the basis for the bidirectional communication between the central nervous system and the gastrointestinal tract driven by neural, hormonal, metabolic, immunological, and microbial signals. Alterations in the gut microbiome composition as observed in inflammatory bowel diseases can modulate brain function and emerging empirical evidence has indicated that interactions among the brain-gut microbiome-axis seem to play a significant role in the pathogenesis of both inflammatory bowel diseases and psychiatric disorders and their comorbidity. Yet, the immunological and molecular mechanisms underlying the co-occurrence of inflammatory bowel diseases and psychological symptoms are still poorly understood. The aim of this narrative review is to highlight contemporary empirical findings supporting a pivotal role of the gut microbiome in the pathophysiology of highly prevalent neuropsychiatric symptoms in inflammatory bowel diseases such as fatigue, depression, and anxiety. Finally, we focus on microbiome modulation as potential treatment option for comorbid neuropsychiatric symptoms in immune-mediated diseases and especially in inflammatory bowel diseases. High-quality clinical trials are required to clarify how microbiome modulation through dietary interventions or probiotic, prebiotic or synbiotic treatment can be used clinically to improve mental health and thus quality of life of patients with inflammatory bowel diseases.

The impact of sleep interventions combined with enhanced nutritional support on sleep quality, nutritional status, pain management, psychological well-being, and quality of life in postoperative colon cancer patients

OBJECTIVE

To investigate the synergistic effects of combined sleep interventions and enhanced nutritional support on postoperative recovery in colon cancer patients, with a focus on sleep quality, nutritional status, pain management, psychological well-being, and quality of life.

METHODS

This randomized controlled trial included 290 postoperative colon cancer patients admitted to the First Affiliated Hospital of Soochow University between May 2021 and May 2023. Participants were randomized into two groups: the intervention group, which received standard care supplemented with sleep and nutritional interventions, and the control group, which received standard care alone. Outcomes were assessed pre- and post-intervention, including the Pittsburgh Sleep Quality Index (PSQI), nutritional markers (serum albumin, prealbumin, body weight, etc.), Visual Analog Scale (VAS) for pain, Self-Rating Anxiety and Depression Scales (SAS, SDS), and EORTC QLQ-C30 quality of life scores.

RESULTS

The intervention group demonstrated significantly greater improvements across all assessed domains compared to the control group ( P < 0.005 after Bonferroni correction). Sleep quality (PSQI: 7.81 vs. 10.43, d = 0.81) and nutritional markers (e.g., prealbumin: 230.19 mg/L vs. 188.01 mg/L, d = 1.21 ) improved markedly. Similarly, reductions in pain (VAS: 2.65 vs. 5.19,d = 1.09 ), anxiety (SAS: 42.03 vs. 49.45, d = 0.88), and depression (SDS: 38.17 vs. 49.77,d = 1.02 ) were observed. Quality of life scores significantly increased in the intervention group compared to the control group (EORTC QLQ-C30: 99.29 vs. 88.41, d = 0.92).

CONCLUSION

The combined intervention of sleep enhancement and nutritional support significantly accelerated postoperative recovery in colon cancer patients, demonstrating synergistic effects that improved physical, psychological, and quality-of-life outcomes. These findings underscore the value of integrating multifaceted interventions into standard postoperative care to optimize recovery trajectories and overall well-being.

Fermented foods affect the seasonal stability of gut bacteria in an Indian rural population

The effect of fermented foods on healthy human gut microbiota structure and function, particularly its seasonal preference and frequent long-term consumption, has been largely uncharacterised. Here, we assess the gut microbiota and metabolite composition of 78 healthy Indian agrarian individuals who differ in the intake of fermented milk and soybean products by seasonal sampling during hot-humid summer, autumn and dry winter. Here we show that, seasonal shifts between the Prevotella- and Bifidobacterium/Ruminococcus-driven community types, or ecological states, and associated fatty acid derivatives, with a bimodal change in Bacteroidota community structure during summer, particularly in fermented milk consumers. Our results associate long-term fermented food consumption with reduced gut microbiota diversity and bacterial load. We identify taxonomic groups that drive the seasonal fluctuation and associated shifts between the two ecological states in gut microbiota. This understanding may pave the way towards developing strategies to sustain a healthy and resilient gut microbiota through dietary interventions.

Corema album Berry Juice as a Protective Agent Against Neurodegeneration

Background/Objectives: Corema album berries are edible fruits from the Iberian Atlantic coast, characterized by a rich polyphenolic composition, which endows their juice with potential protective effects against neurodegeneration. This study aimed to evaluate the potential of the relatively lesser-known C. album berries as a novel neuroprotective agent against neurodegenerative diseases. Methods: The phenolic compounds of the juice were characterized using UHPLC-HRMS (Orbitrap). The SH-SY5Y neuroblastoma line was used to determine the preventive effect of the juice against H2O2-induced oxidative stress. Furthermore, neuronal cells were differentiated into dopaminergic and cholinergic lines and exposed to 6-hydroxydopamine and okadaic acid, respectively, to simulate in vitro models of Parkinson's disease and Alzheimer's disease. The ability of the juice to enhance neuronal viability under toxic conditions was examined. Additionally, its inhibitory effects on neuroprotective-related enzymes, including MAO-A and MAO-B, were assessed in vitro. Results: Phytochemical characterization reveals that 5-O-caffeoylquinic acid constitutes 80% of the total phenolic compounds. Higher concentrations of the juice effectively protected both differentiated and undifferentiated SH-SY5Y cells from H2O2-induced oxidative damage, reducing oxidative stress by approximately 20% and suggesting a dose-dependent mechanism. Moreover, the presence of the juice significantly enhanced the viability of dopaminergic and cholinergic cells exposed to neurotoxic agents. In vitro, the juice inhibited the activity of MAO-A (IC50 = 87.21 µg/mL) and MAO-B (IC50 = 56.50 µg/mL). Conclusions: While these findings highlight C. album berries as a promising neuroprotective agent, further research is required to elucidate its neuroprotective mechanisms in cell and animal models and, ultimately, in human trials.

Fibre & fermented foods: differential effects on the microbiota-gut-brain axis

The ability to manipulate brain function through the communication between the microorganisms in the gastrointestinal tract and the brain along the gut-brain axis has emerged as a potential option to improve cognitive and emotional health. Dietary composition and patterns have demonstrated a robust capacity to modulate the microbiota-gut-brain axis. With their potential to possess pre-, pro-, post-, and synbiotic properties, dietary fibre and fermented foods stand out as potent shapers of the gut microbiota and subsequent signalling to the brain. Despite this potential, few studies have directly examined the mechanisms that might explain the beneficial action of dietary fibre and fermented foods on the microbiota-gut-brain axis, thus limiting insight and treatments for brain dysfunction. Herein, we evaluate the differential effects of dietary fibre and fermented foods from whole food sources on cognitive and emotional functioning. Potential mediating effects of dietary fibre and fermented foods on brain health via the microbiota-gut-brain axis are described. Although more multimodal research that combines psychological assessments and biological sampling to compare each food type is needed, the evidence accumulated to date suggests that dietary fibre, fermented foods, and/or their combination within a psychobiotic diet can be a cost-effective and convenient approach to improve cognitive and emotional functioning across the lifespan.

The Identification of Potential Anti-Depression/Anxiety Drug Targets by Stress-Induced Rat Brain Regional Proteome and Network Analyses

Depression and anxiety disorders are prevalent stress-related neuropsychiatric disorders and involve multiple molecular changes and dysfunctions across various brain regions. However, the specific and shared pathophysiological mechanisms occurring in these regions remain unclear. Previous research used a rat model of chronic mild stress (CMS) to segregate and identify depression-susceptible, anxiety-susceptible, and insusceptible groups; then the proteomes of six distinct brain regions (the hippocampus, prefrontal cortex, hypothalamus, pituitary, olfactory bulb, and striatum) were separately and quantitatively analyzed. To gain a comprehensive and systematic understanding of the molecular abnormalities, this study aimed to investigate and compare differential proteomics data from the six regions. Differentially expressed proteins (DEPs) were identified in between specific regions and across all regions and subjected to a series of bioinformatics analyses. Regional comparisons showed that stress-induced proteomic changes and corresponding gene ontology and pathway enrichments were largely distinct, attributable to differences in cell populations, protein compositions, and brain functions of these areas. Additionally, a notable degree of overlap in the significantly enriched terms was identified, potentially suggesting strong connections in the enrichment across different regions. Furthermore, intra-regional and inter-regional protein-protein interaction networks and drug-target-DEP networks were constructed. Integrated analysis of the three association networks in the six regions, along with the DisGeNET database, identified ten DEPs as potential targets for anti-depression/anxiety drugs. Collectively, these findings revealed commonalities and differences across different brain regions at the protein level induced by CMS, and identified several novel protein targets for the development of new therapeutics for depression and anxiety.

Supplementation with Lactobacillus helveticus NS8 alleviated behavioral, neural, endocrine, and microbiota abnormalities in an endogenous rat model of depression

Introduction

Major depressive disorder is a condition involving microbiota-gut-brain axis dysfunction. Increasing research aims to improve depression through gut microbiota regulation, including interventions such as probiotics, prebiotics, and fecal microbiota transplants. However, most research focuses on exogenous depression induced by chronic stress or drugs, with less attention given to endogenous depression. Additionally, research on gut mycobiota in depression is significantly less than that on gut bacteria.

Methods

In the present study, Wistar-Kyoto rats were used as an endogenous depression and treatment-resistant depression model, while Wistar rats served as controls. Differences between the two rat strains in behavior, gut bacteria, gut mycobiota, nervous system, endocrine system, immune system, and gut barrier were evaluated. Additionally, the effects of Lactobacillus helveticus NS8 supplementation were investigated.

Results

Wistar-Kyoto rats demonstrated increased depressive-like behaviors in the forced swimming test, reduced sucrose preference in the sucrose preference test, and decreased locomotor activity in the open field test. They also exhibited abnormal gut bacteria and mycobiota, characterized by higher bacterial α-diversity but lower fungal α-diversity, along with increased butyrate, L-tyrosine, and L-phenylalanine biosynthesis from bacteria. Furthermore, these rats showed dysfunction in the microbiota-gut-brain axis, evidenced by a hypo-serotonergic system, hyper-noradrenergic system, defective hypothalamic-pituitary-adrenal axis, compromised gut barrier integrity, heightened serum inflammation, and diminished gut immunity. A 1-month L. helveticus NS8 intervention increased the fecal abundance of L. helveticus; reduced the abundance of Bilophila and Debaryomycetaceae; decreased immobility time but increased climbing time in the forced swimming test; reduced hippocampal corticotropin-releasing hormone levels; decreased hypothalamic norepinephrine levels; increased hippocampal glucocorticoid receptor, brain-derived neurotrophic factor dopamine, and 5-hydroxyindoleacetic acid content; and improved the gut microbiota, serotonergic, and noradrenergic system.

Conclusion

The depressive phenotype of Wistar-Kyoto rats is not only attributed to their genetic context but also closely related to their gut microbiota. Abnormal gut microbiota and a dysfunctional microbiota-gut-brain axis play important roles in endogenous depression, just as they do in exogenous depression. Supplementing with probiotics such as L. helveticus NS8 is likely a promising approach to improve endogenous depression and treatment-resistant depression.

An Anti-Inflammatory Diet and Its Potential Benefit for Individuals with Mental Disorders and Neurodegenerative Diseases-A Narrative Review

This narrative review synthesizes current evidence regarding anti-inflammatory dietary patterns and their potential benefits for individuals with mental disorders and neurodegenerative diseases. Chronic low-grade inflammation is increasingly recognized as a key factor in the etiology and progression of these conditions. The review examines the evidence for the anti-inflammatory and neuroprotective properties of dietary components and food groups, focusing on whole foods rather than specific nutrients or supplements. Key dietary components showing potential benefits include fruits and vegetables (especially berries and leafy greens), whole grains, legumes, fatty fish rich in omega-3, nuts (particularly walnuts), olive oil, and fermented foods. These foods are generally rich in antioxidants, dietary fiber, and bioactive compounds that may help modulate inflammation, support gut health, and promote neuroprotection. Conversely, ultra-processed foods, red meat, and sugary beverages may be harmful. Based on this evidence, we designed the Brain Anti-Inflammatory Nutrition (BrAIN) diet. The mechanisms of this diet include the modulation of the gut microbiota and the gut-brain axis, the regulation of inflammatory pathways, a reduction in oxidative stress, and the promotion of neuroplasticity. The BrAIN diet shows promise as an aid to manage mental and neurodegenerative disorders.

Effects of kefir consumption on gut microbiota and health outcomes in women with polycystic ovary syndrome

Polycystic Ovary Syndrome (PCOS), which is common among women of reproductive age, is characterized by low-grade chronic inflammation and is associated with several health problems and dysbiosis. Kefir has been shown to have many beneficial health effects; however, its effect on PCOS is unknown. This study aimed to examine the effect of kefir on the intestinal microbiota and health outcomes in PCOS. In this intervention study, 17 women with PCOS consumed 250 mL/day of kefir (containing Lactobacillus kefiranofaciens subsp. kefiranofaciens, Lactobacillus kefiranofaciens subsp. kefirgranum, Lactobacillus kefiri, Lactobacillus acidophilus, Lactobacillus parakefiri, Lactobacillus bulgaricus, Lactobacillus reuteri, Lactobacillus casei, Lactobacillus fermentum, Lactobacillus helveticus, Lactococcus lactis, Leuconostoc mesentereoides, Bifidobacterium bifidum, Streptococcus thermophilus, Kluyveromyces marxianus, Kluyveromyces lactis, Acetobacter pasteurianus, and Saccharomyces cerevisiae) for 8 weeks. Food consumption and physical activity records, anthropometrical measurements, quality of life, and fecal and blood samples were taken at the study's beginning and end. Quality of life in mental health (58.8 ± 15.08; 64.0 ± 15.23, respectively) and physical function (95.00 and 100.00, respectively) categories showed a significant increase after kefir intervention (p < .05). Additionally, Interleukin-6 (IL-6), one of the inflammatory cytokines, significantly decreased (174.00 and 109.10 ng/L, respectively) (p < .05). The intestinal barrier permeability was evaluated with zonulin, and no significant change was observed. Gut microbiota analysis showed that while the relative abundance of the class Bacilli and genus Lactococcus significantly increased, the genus Holdemania decreased with kefir consumption (p < .05). In conclusion, kefir appears to be beneficial for improving the microbiota and some health outcomes, like reducing inflammation and improving quality of life in PCOS. Therefore, kefir may be useful in the treatment of PCOS.

Treatment resistant late-life depression: A narrative review of psychosocial risk factors, non-pharmacological interventions, and the role of clinical phenotyping

BACKGROUND

Treatment resistant depression (TRD) is a subset of major depressive disorder (MDD) in which symptoms do not respond to front line therapies. In older adults, the assessment and treatment of TRD is complicated by psychosocial risk factors unique to this population, as well as a relative paucity of research.

METHODS

Narrative review aimed at (1) defining TRLLD for clinical practice and research; (2) describing psychosocial risk factors; (3) reviewing psychological and non-pharmacological treatments; (4) discussing the role of clinical phenotyping for personalized treatment; and (5) outlining research priorities.

RESULTS

Our definition of TRLLD centers on response to medication and neuromodulation in primary depressive disorders. Psychosocial risk factors include trauma and early life adversity, chronic physical illness, social isolation, personality, and barriers to care. Promising non-pharmacological treatments include cognitive training, psychotherapy, and lifestyle interventions. The utility of clinical phenotyping is highlighted by studies examining the impact of comorbidities, symptom dimensions (e.g., apathy), and structural/functional brain changes.

LIMITATIONS

There is a relative paucity of TRLLD research. This limits the scope of empirical data from which to derive reliable patterns and complicates efforts to evaluate the literature quantitatively.

CONCLUSIONS

TRLLD is a complex disorder that demands further investigation given our aging population. While this review highlights the promising breadth of TRLLD research to date, more research is needed to help elucidate, for example, the optimal timing for implementing risk mitigation strategies, the value of collaborative care approaches, specific treatment components associated with more robust response, and phenotyping to help inform treatment decisions.

Human Gut Microbiota for Diagnosis and Treatment of Depression

Nowadays, depressive disorder is spreading rapidly all over the world. Therefore, attention to the studies of the pathogenesis of the disease in order to find novel ways of early diagnosis and treatment is increasing among the scientific and medical communities. Special attention is drawn to a biomarker and therapeutic strategy through the microbiota-gut-brain axis. It is known that the symbiotic interactions between the gut microbes and the host can affect mental health. The review analyzes the mechanisms and ways of action of the gut microbiota on the pathophysiology of depression. The possibility of using knowledge about the taxonomic composition and metabolic profile of the microbiota of patients with depression to select gene compositions (metagenomic signature) as biomarkers of the disease is evaluated. The use of in silico technologies (machine learning) for the diagnosis of depression based on the biomarkers of the gut microbiota is given. Alternative approaches to the treatment of depression are being considered by balancing the microbial composition through dietary modifications and the use of additives, namely probiotics, postbiotics (including vesicles) and prebiotics as psychobiotics, and fecal transplantation. The bacterium Faecalibacterium prausnitzii is under consideration as a promising new-generation probiotic and auxiliary diagnostic biomarker of depression. The analysis conducted in this review may be useful for clinical practice and pharmacology.

Gut health benefits and associated systemic effects provided by functional components from the fermentation of natural matrices

Recently, the role of the gut microbiota in metabolic health, immunity, behavioral balance, longevity, and intestine comfort has been the object of several studies from scientific communities. They were encouraged by a growing interest from food industries and consumers toward novel fermented ingredients and formulations with powerful biological effects, such as pre, pro, and postbiotic products. Depending on the selected strains, the operating conditions, the addition of suitable reagents or enzymes, the equipment, and the reactor configurations, functional compounds with high bioactivity, such as short-chain fatty acids, gamma-aminobutyric acid, bioactive peptides, and serotonin, can be enhanced and/or produced through fermentation of several vegetable matrices. Otherwise, their formation can also be promoted directly in the gut after the dietary intake of fermented foods: In this case, fermentation will aim to increase the content of precursor substances, such as indigestible fibers, polyphenols, some amino acids, and resistant starch, which can be potentially metabolized by endogenous gut microorganisms and converted in healthy molecules. This review provides an overview of the main functional components currently investigated in literature and the associated gut health benefits. The current state of the art about fermentation technology as a promising functionalization tool to promote the direct or indirect formation of gut-health-enhancing components was deepened, highlighting the importance of optimizing microorganism selection, system setups, and process conditions according to the target compound of interest. The collected data suggested the possibility of gaining novel functional food ingredients or products rich in functional molecules through fermentation without performing additional extraction and purification stages, which are needed when conventional culture broths are used.

Fermented foods and gastrointestinal health: underlying mechanisms

Although fermentation probably originally developed as a means of preserving food substrates, many fermented foods (FFs), and components therein, are thought to have a beneficial effect on various aspects of human health, and gastrointestinal health in particular. It is important that any such perceived benefits are underpinned by rigorous scientific research to understand the associated mechanisms of action. Here, we review in vitro, ex vivo and in vivo studies that have provided insights into the ways in which the specific food components, including FF microorganisms and a variety of bioactives, can contribute to health-promoting activities. More specifically, we draw on representative examples of FFs to discuss the mechanisms through which functional components are produced or enriched during fermentation (such as bioactive peptides and exopolysaccharides), potentially toxic or harmful compounds (such as phytic acid, mycotoxins and lactose) are removed from the food substrate, and how the introduction of fermentation-associated live or dead microorganisms, or components thereof, to the gut can convey health benefits. These studies, combined with a deeper understanding of the microbial composition of a wider variety of modern and traditional FFs, can facilitate the future optimization of FFs, and associated microorganisms, to retain and maximize beneficial effects in the gut.

Dietary habits, depression and obesity: an intricate relationship to explore in pediatric preventive strategies

Obesity and depression represent major health problems due to their high prevalence and morbidity rates. Numerous evidences elucidated the connections between dietary habits and the incidence or severity of depression. This overview aims to investigate the intricate relationship between dietary patterns and depression with the objective of elaborating preventive strategies for childhood obesity. Literature data recognized that there is a link between mood and food choices, with certain foods selected for their impact on the brain's reward centers. This behavior parallels the one observed in substance addiction, suggesting a specific neural mechanism for food addiction that contributes to overeating and obesity. It is important to note the significant correlation between obesity and depression, indicating a shared biological pathway influencing these conditions. Stress substantially affects also eating behaviors, often leading to increased consumption of pleasurable and rewarding foods. This can trigger a cycle of overeating, weight gain, and psychological distress, exacerbating mood disorders and obesity. In addition, consumption of certain types of foods, especially "comfort foods" high in fat and calories, may provide temporary relief from symptoms of depression, but can lead to long-term obesity and further mental health problems. Understanding these complex interactions is critical to developing preventive strategies focusing on dietary, emotional, and environmental factors, thereby reducing the risk of obesity and mood disorders.

Fermented foods: Harnessing their potential to modulate the microbiota-gut-brain axis for mental health

Over the past two decades, whole food supplementation strategies have been leveraged to target mental health. In addition, there has been increasing attention on the ability of gut microbes, so called psychobiotics, to positively impact behaviour though the microbiota-gut-brain axis. Fermented foods offer themselves as a combined whole food microbiota modulating intervention. Indeed, they contain potentially beneficial microbes, microbial metabolites and other bioactives, which are being harnessed to target the microbiota-gut-brain axis for positive benefits. This review highlights the diverse nature of fermented foods in terms of the raw materials used and type of fermentation employed, and summarises their potential to shape composition of the gut microbiota, the gut to brain communication pathways including the immune system and, ultimately, modulate the microbiota-gut-brain axis. Throughout, we identify knowledge gaps and challenges faced in designing human studies for investigating the mental health-promoting potential of individual fermented foods or components thereof. Importantly, we also suggest solutions that can advance understanding of the therapeutic merit of fermented foods to modulate the microbiota-gut-brain axis.

Probiotic, prebiotic, synbiotic and fermented food supplementation in psychiatric disorders: A systematic review of clinical trials

The use of probiotics, prebiotics, synbiotics or fermented foods can modulate the gut-brain axis and constitute a potentially therapeutic intervention in psychiatric disorders. This systematic review aims to identify current evidence regarding these interventions in the treatment of patients with DSM/ICD psychiatric diagnoses. Forty-seven articles from 42 studies met the inclusion criteria. Risk of bias was assessed in all included studies. Major depression was the most studied disorder (n = 19 studies). Studies frequently focused on schizophrenia (n = 11) and bipolar disorder (n = 5) and there were limited studies in anorexia nervosa (n = 4), ADHD (n = 3), Tourette (n = 1), insomnia (n = 1), PTSD (n = 1) and generalized anxiety disorder (n = 1). Except in MDD, current evidence does not clarify the role of probiotics and prebiotics in the treatment of mental illness. Several studies point to an improvement in the immune and inflammatory profile (e.g. CRP, IL6), which may be a relevant mechanism of action of the therapeutic response identified in these studies. Future research should consider lifestyle and dietary habits of patients as possible confounders that may influence inter-individual treatment response.

The functionalities and applications of whey/whey protein in fermented foods: a review

Whey, a major by-product of cheese production, is primarily composed of whey protein (WP). To mitigate environmental pollution, it is crucial to identify effective approaches for fully utilizing the functional components of whey or WP to produce high-value-added products. This review aims to illustrate the active substances with immunomodulatory, metabolic syndrome-regulating, antioxidant, antibacterial, and anti-inflammatory activities produced by whey or WP through fermentation processes, and summarizes the application and the effects of whey or WP on nutritional properties and health promotion in fermented foods. All these findings indicate that whey or WP can serve as a preservative, a source of high-protein dietary, and a source of physiologically active substance in the production of fermented foods. Therefore, expanding the use of whey or WP in fermented foods is of great importance for converting whey into value-added products, as well as reducing whey waste and potential contamination.

Could psychobiotics and fermented foods improve mood in middle-aged and older women?

Menopause is a natural physiological phase during which women experience dramatic hormonal fluctuations. These lead to many symptoms, such as depression and anxiety, which, in turn, can negatively affect quality of life. Proper nutrition has an influential role in alleviating depression as well as anxiety. It is well known that gut microbiota dysbiosis contributes to the development of mood disorder. There is mounting evidence that modulating the gut-brain axis may aid in improving mood swings. In this context, this narrative review summarizes recent findings on how aging changes the composition of the gut microbiota and on the association between gut microbiota and mood disorders. In addition, it evaluates the effectiveness of psychobiotics and fermented foods in treating mood swings in middle-aged and older women. A search was done using PubMed, Scopus, and Google Scholar, and thirteen recent articles are included in this review. It is evident that psychobiotic supplementation and fermented foods can improve mood swings via several routes. However, these conclusions are based on only a few studies in middle-aged and older women. Therefore, long-term, well-designed randomized controlled trials are required to fully evaluate whether psychobiotics and fermented foods can be used to treat mood swings in this population.

Mood Disorders: The Gut Bacteriome and Beyond

Knowledge of the microbiome-gut-brain axis has revolutionized the field of psychiatry. It is now well recognized that the gut bacteriome is associated with, and likely influences, the pathogenesis of mental disorders, including major depressive disorder and bipolar disorder. However, while substantial advances in the field of microbiome science have been made, we have likely only scratched the surface in our understanding of how these ecosystems might contribute to mental disorder pathophysiology. Beyond the gut bacteriome, research into lesser explored components of the gut microbiome, including the gut virome, mycobiome, archaeome, and parasitome, is increasingly suggesting relevance in psychiatry. The contribution of microbiomes beyond the gut, including the oral, lung, and small intestinal microbiomes, to human health and pathology should not be overlooked. Increasing both our awareness and understanding of these less traversed fields of research are critical to improving the therapeutic benefits of treatments targeting the gut microbiome, including fecal microbiome transplantation, postbiotics and biogenics, and dietary intervention. Interdisciplinary collaborations integrating systems biology approaches are required to fully elucidate how these different microbial components and distinct microbial niches interact with each other and their human hosts. Excitingly, we may be at the start of the next microbiome revolution and thus one step closer to informing the field of precision psychiatry to improve outcomes for those living with mental illness.

Association between Dietary Intake of Live Microbes and Chronic Constipation in Adults

BACKGROUND

Chronic constipation (CC) is a common gut health problem, and the role of live dietary microbes in CC is unclear.

OBJECTIVE

This study aimed to investigate the relationship between dietary live microbes consumption and CC.

METHODS

Using the National Health and Nutrition Examination Survey data (2005-2010), 11,170 adults who completed the 24-h face-to-face dietary recall and bowel health questionnaire were identified. CC was defined by the Bristol Stool Form Scale. Dietary live microbes intake was classified as low, medium, and high. Additionally, combined medium and high categories (MedHi) were analyzed. Multivariate regression models were constructed to assess the association between dietary intake of live microbes and CC.

RESULTS

In the weighted sample, the age-adjusted CC prevalence was 7.06% (95% confidence interval [CI]: 6.45, 7.67). In multivariate regression models, after controlling for potential confounders race/ethnicity, sex, body mass index, education, poverty, depression, caffeine intake, and alcohol intake, a significant inverse association between dietary live microbes consumption and CC was observed (odds ratio [OR]: 0.77, 95% CI: 0.61, 0.97, P-trend = 0.061).

CONCLUSIONS

Our findings suggest that a high dietary live microbes consumption may be associated with lower odds of CC. However, further prospective studies are essential to confirm its effectiveness in reducing CC occurrence.

Nutritional and potential health benefits of fermented food proteins

BACKGROUND

Protein fermentation continues to gain popularity as a result of several factors, including the cost-effectiveness of the process and the positive correlation of fermented protein consumption, with a reduced risk of developing diet-related diseases such as diabetes and cardiovascular disorders, as well as their enhanced nutritional and techno-functional properties. Nonetheless, the nutritional and health benefits of food protein fermentation such as enhanced nutrient bioavailability, reduced antinutritional factors (ANFs) and enriched bioactive peptides (BAPs) are often overlooked. The present study reviewed recent work on the influence of protein fermentation on nutrition and health. In total, 322 eligible studies were identified on the Scopus and Google Scholar databases out of which 69 studies were evaluated based on our inclusion criteria.

RESULTS

Fermented protein ingredients and products show reduced ANF content, enhanced digestibility and bioavailability, and increased antioxidant and other biological activities, such as probiotic, prebiotic, angiotensin-converting enzyme inhibitory and antihypertensive properties. In addition, co-products in protein fermentation such as BAPs possess and could contribute additional sensory and flavor properties, degrade toxins, and reduce allergens in foods.

CONCLUSION

Thus, fermentation is not only a method for food preservation, but also serves as a means for producing functional food products for consumer health promotion and nutrition enrichment. © 2023 Society of Chemical Industry.

Fermented foods, their microbiome and its potential in boosting human health

Fermented foods (FFs) are part of the cultural heritage of several populations, and their production dates back 8000 years. Over the last ~150 years, the microbial consortia of many of the most widespread FFs have been characterised, leading in some instances to the standardisation of their production. Nevertheless, limited knowledge exists about the microbial communities of local and traditional FFs and their possible effects on human health. Recent findings suggest they might be a valuable source of novel probiotic strains, enriched in nutrients and highly sustainable for the environment. Despite the increasing number of observational studies and randomised controlled trials, it still remains unclear whether and how regular FF consumption is linked with health outcomes and enrichment of the gut microbiome in health-associated species. This review aims to sum up the knowledge about traditional FFs and their associated microbiomes, outlining the role of fermentation with respect to boosting nutritional profiles and attempting to establish a link between FF consumption and health-beneficial outcomes.

Probiotics and Fecal Microbiota Transplantation in Major Depression: Doxa or Episteme?

In the human body, eukaryotic somatic cells and prokaryotic microorganisms live together. In this state, the body can be viewed as a "superorganism." Symbiotic life with commensal microorganisms can be observed in almost every part of the body. Intestinal microbiota plays an important role in health and disease, and in shaping and regulating neuronal functions from the intrauterine period to the end of life. Microbiota-based treatment opportunities are becoming more evident in both understanding the etiopathogenesis and treatment of neuropsychiatric disorders, especially depression. Antidepressant drugs, which are the first choice in the treatment of depression, also have antimicrobial and immunomodulatory mechanisms of action. From these perspectives, direct probiotics and fecal microbiota transplantation are treatment options to modulate microbiota composition. There are few preclinical and clinical studies on the effectiveness and safety of these applications in depression. The information obtained from these studies may still be at a doxa level. However, the probability that this information will become episteme in the future seems to be increasing.

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.

Food4healthKG: Knowledge graphs for food recommendations based on gut microbiota and mental health

Food is increasingly acknowledged as a powerful means to promote and maintain mental health. The introduction of the gut-brain axis has been instrumental in understanding the impact of food on mental health. It is widely reported that food can significantly influence gut microbiota metabolism, thereby playing a pivotal role in maintaining mental health. However, the vast amount of heterogeneous data published in recent research lacks systematic integration and application development. To remedy this, we construct a comprehensive knowledge graph, named Food4healthKG, focusing on food, gut microbiota, and mental diseases. The constructed workflow includes the integration of numerous heterogeneous data, entity linking to a normalized format, and the well-designed representation of the acquired knowledge. To illustrate the availability of Food4healthKG, we design two case studies: the knowledge query and the food recommendation based on Food4healthKG. Furthermore, we propose two evaluation methods to validate the quality of the results obtained from Food4healthKG. The results demonstrate the system's effectiveness in practical applications, particularly in providing convincing food recommendations based on gut microbiota and mental health. Food4healthKG is accessible at https://github.com/ccszbd/Food4healthKG.

Evaluation of the reliability and validity of the health regulatory focus scale in Chinese samples

This study sought to validate the psychometric properties of the Health Regulatory Focus Scale (HRFS), emphasizing its manifestation and association with personality traits in a Chinese context. Originally developed by Ferrer, the HRFS gauges individuals' inclinations either to avoid negative health outcomes (prevention focus) or achieve positive health outcomes (promotion focus). Our cross-sectional analysis involved a diverse sample of 652 Chinese participants, averaging 39.6 years in age (SD = 9.39). Data were analyzed using SPSS and AMOS, and both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were employed to assess the HRFS's factor structure. Additionally, we evaluated convergent and discriminant validity, criterion-related validity, internal consistency reliability, and test-retest reliability. The CFA results (CFI = 0.985, TLI = 0.971, RMSEA = 0.059, and SRMR = 0.047), combined with McDonald's omega value (0.916) and the test-retest correlation coefficient (0.78) for the HRFS, underscore its robust construct validity and reliability. Furthermore, the promotion dimension of the HRFS exhibited significant positive correlations with all dimensions of the Chinese Adjectives Short Scale of Big-Five Factor Personality (BFFP-CAS-S). In conclusion, the HRFS's Chinese adaptation offers a reliable and valid instrument for assessing health regulatory focus.

Reproducible microbiome composition signatures of anxiety and depressive symptoms

The gut microbiome is a significant contributor to mental health, with growing evidence linking its composition to anxiety and depressive disorders. Gut microbiome composition is associated with signs of anxiety and depression both in clinically diagnosed mood disorders and subclinically in the general population and may be influenced by dietary fibre intake and the presence of chronic pain. We provide an update of current evidence on the role of gut microbiome composition in depressive and anxiety disorders or symptoms by reviewing available studies. Analysing data from three independent cohorts (osteoarthritis 1 (OA1); n = 46, osteoarthritis 2 (OA2); n = 58, and healthy controls (CON); n = 67), we identified microbial composition signatures of anxiety and depressive symptoms at genus level and cross-validated our findings performing meta-analyses of our results with results from previously published studies. The genera Bifidobacterium (fixed-effect beta (95% CI) = -0.22 (-0.34, -0.10), p = 3.90e-04) and Lachnospiraceae NK4A136 group (fixed-effect beta (95% CI) = -0.09 (-0.13, -0.05), p = 2.53e-06) were found to be the best predictors of anxiety and depressive symptoms, respectively, across our three cohorts and published literature taking into account demographic and lifestyle covariates, such as fibre intake. The association with anxiety was robust in accounting for heterogeneity between cohorts and supports previous observations of the potential prophylactic effect of Bifidobacterium against anxiety symptoms.

The inhibitory effects of plant additives on biogenic amine formation in fermented foods - a review

Fermented food has unique properties and high nutritional value, and thus, should constitute a basic element of a balanced and health-promoting diet. However, it can accumulate considerable amount of biogenic amines (BAs), which ingested in excess can lead to adverse health effects. The application of plant-derived additives represents a promising strategy to ensure safety or enhance the functional and organoleptic properties of fermented food. This review summarizes currently available data on the application of plant-origin additives with the aim to reduce BA content in fermented products. The importance of ensuring fermented food safety has been highlighted considering the growing evidence of beneficial effects resulting from the consumption of this type of food, as well as the increasing number of individuals sensitive to BAs. The examined plant-origin additives reduced the BA concentration to varying degrees, and their efficacy depended on the type of additive, matrix, autochthonous, and inoculated microorganisms, as well as the manufacturing conditions. The main mechanisms of action include antimicrobial effects and the inhibition of microbial decarboxylases. Further research on the optimization of bioactive substances extraction, standardization of their chemical composition, and development of detailed procedures for its use in fermented products manufacturing are needed.

Physical Characterization of a Novel Carrot Juice Whey-Enriched Beverage Fermented with Milk or Water Kefir Starter Cultures

The purpose of this work was to evaluate the selected physicochemical, rheological, and sensory properties of a new whey-enriched carrot juice beverage (carrot juice: whey ratios of 100:0; 95:5; 85:15; 75:25; 65:35) fermented with milk or water kefir starter cultures over a storage period of 21 days (at 4 ± 1 °C). In general, for all tested samples, the values of total soluble solids, pH, and density decreased with increasing storage time. In contrast, the values of ethanol, degree of fermentation, and total dissolved solids increased with the prolongation of the storage time. Furthermore, it was found that all the model samples exhibited pseudoplastic behavior. Based on the sensory analysis performed, samples containing 25% (w/w) whey were evaluated as the most acceptable. Last but not least, the present study can serve as a basis for optimizing the manufacturing technology of a novel fermented vegetable beverage enriched with whey.

Non-canonical pathways in the pathophysiology and therapeutics of bipolar disorder

Bipolar disorder (BD) is characterized by extreme mood swings ranging from manic/hypomanic to depressive episodes. The severity, duration, and frequency of these episodes can vary widely between individuals, significantly impacting quality of life. Individuals with BD spend almost half their lives experiencing mood symptoms, especially depression, as well as associated clinical dimensions such as anhedonia, fatigue, suicidality, anxiety, and neurovegetative symptoms. Persistent mood symptoms have been associated with premature mortality, accelerated aging, and elevated prevalence of treatment-resistant depression. Recent efforts have expanded our understanding of the neurobiology of BD and the downstream targets that may help track clinical outcomes and drug development. However, as a polygenic disorder, the neurobiology of BD is complex and involves biological changes in several organelles and downstream targets (pre-, post-, and extra-synaptic), including mitochondrial dysfunction, oxidative stress, altered monoaminergic and glutamatergic systems, lower neurotrophic factor levels, and changes in immune-inflammatory systems. The field has thus moved toward identifying more precise neurobiological targets that, in turn, may help develop personalized approaches and more reliable biomarkers for treatment prediction. Diverse pharmacological and non-pharmacological approaches targeting neurobiological pathways other than neurotransmission have also been tested in mood disorders. This article reviews different neurobiological targets and pathophysiological findings in non-canonical pathways in BD that may offer opportunities to support drug development and identify new, clinically relevant biological mechanisms. These include: neuroinflammation; mitochondrial function; calcium channels; oxidative stress; the glycogen synthase kinase-3 (GSK3) pathway; protein kinase C (PKC); brain-derived neurotrophic factor (BDNF); histone deacetylase (HDAC); and the purinergic signaling pathway.

The Role of Gut Microbiota in Anxiety, Depression, and Other Mental Disorders as Well as the Protective Effects of Dietary Components

The number of individuals experiencing mental disorders (e.g., anxiety and depression) has significantly risen in recent years. Therefore, it is essential to seek prevention and treatment strategies for mental disorders. Several gut microbiota, especially Firmicutes and Bacteroidetes, are demonstrated to affect mental health through microbiota-gut-brain axis, and the gut microbiota dysbiosis can be related to mental disorders, such as anxiety, depression, and other mental disorders. On the other hand, dietary components, including probiotics (e.g., Lactobacillus and Bifidobacterium), prebiotics (e.g., dietary fiber and alpha-lactalbumin), synbiotics, postbiotics (e.g., short-chain fatty acids), dairy products, spices (e.g., Zanthoxylum bungeanum, curcumin, and capsaicin), fruits, vegetables, medicinal herbs, and so on, could exert protective effects against mental disorders by enhancing beneficial gut microbiota while suppressing harmful ones. In this paper, the mental disorder-associated gut microbiota are summarized. In addition, the protective effects of dietary components on mental health through targeting the gut microbiota are discussed. This paper can be helpful to develop some dietary natural products into pharmaceuticals and functional foods to prevent and treat mental disorders.

Potential neuroprotective effects of fermented foods and beverages in old age: a systematic review

Purpose

Numerous articles have recently studied the involvement of the gut microbiota in neurological diseases. Aging is associated with changes in the microbiome, which implies a reduction in microbial biodiversity among other changes. Considering that the consumption of a fermented-food diet improves intestinal permeability and barrier function, it seems of interest to study its participation in the prevention of neurodegenerative diseases. This article reviews existing studies to establish whether the consumption of fermented foods and fermented beverages prevents or ameliorates neurodegenerative decline in old age.

Methods

The protocol used was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Details of the protocol for this systematic review are registered on PROSPERO (CRD42021250921).

Results

Out of 465 articles identified in the Pubmed, Scopus, and Cochrane Library databases, a total of 29 that examined the relationship of the consumption of fermented products with cognitive impairment in old people were selected (22 cohort, 4 case-control, and 3 cross-sectional studies). The results suggest that low-to-moderate alcohol consumption and daily intake of coffee, soy products, and fermented-food diets in general are associated with a lower risk of dementia and Alzheimer's disease.

Conclusion

Daily consumption of fermented foods and beverages, either alone or as part of a diet, has neuroprotective effects and slows cognitive decline in old people.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=250921, identifier: CRD42021250921.

Stress, inflammation, microbiome and depression

Psychiatric disorders are mental illnesses involving changes in mood, cognition and behavior. Their prevalence has rapidly increased in the last decades. One of the most prevalent psychiatric disorders is major depressive disorder (MDD), a debilitating disease lacking efficient treatments. Increasing evidence shows that microbial and immunological changes contribute to the pathophysiology of depression and both are modulated by stress. This bidirectional relationship constitutes the brain-gut axis involving various neuroendocrine, immunological, neuroenterocrine and autonomic pathways. The present review covers the most recent findings on the relationships between stress, the gut microbiome and the inflammatory response and their contribution to depression.

Probiotic therapy, African fermented foods and food-derived bioactive peptides in the management of SARS-CoV-2 cases and other viral infections

The current paper focuses on the impact of probiotics, African fermented foods and bioactive peptides on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection severity and related viral infections. Using probiotics or bioactive peptides as therapeutic adjuncts appears superior to standard care alone. Probiotics play critical roles in innate and adaptive immune modulation by balancing the gut microbiota to combat viral infections, secondary bacterial infections and microbial dysbiosis. African fermented foods contain abundant potential probiotic microorganisms such as the lactic acid bacteria (LAB), Saccharomyces, and Bacillus. More so, fermented food-derived bioactive peptides play vital roles in preventing cardiovascular diseases, hypertension, lung injury, diabetes, and other COVID-19 comorbidities. Regularly incorporating potential probiotics and bioactive peptides into diets should enable a build-up of the benefits in the body system that may result in a better prognosis, especially in COVID-19 patients with underlying complexities. Despite the reported therapeutic potentials of probiotics and fermented foods, numerous setbacks exist regarding their application in disease management. These shortfalls underscore an evident need for more studies to evaluate the specific potentials of probiotics and traditional fermented foods in ameliorating SARS-CoV-2 and other viral infections.

Food, gut barrier dysfunction, and related diseases: A new target for future individualized disease prevention and management

Dysfunction of gut barrier is known as "leaky gut" or increased intestinal permeability. Numerous recent scientific evidences showed the association between gut dysfunction and multiple gastrointestinal tract (GI) and non-GI diseases. Research also demonstrated that food plays a crucial role to cause or remedy gut dysfunction related to diseases. We reviewed recent articles from electronic databases, mainly PubMed. The data were based on animal models, cell models, and human research in vivo and in vitro models. In this comprehensive review, our aim focused on the relationship between dietary factors, intestinal permeability dysfunction, and related diseases. This review synthesizes currently available literature and is discussed in three parts: (a) the mechanism of gut barrier and function, (b) food and dietary supplements that may promote gut health, and food or medication that may alter gut function, and (c) a table that organizes the synthesized information by general mechanisms for diseases related to leaky gut/intestinal permeability and associated dietary influences. With future research, dietary intervention could be a new target for individualized disease prevention and management.

The association between gut-health promoting diet and depression: A mediation analysis

BACKGROUND

Recent research has highlighted the relevance of a gut-health promoting diet as a possible treatment and prevention for depression. A dietary pattern with consumption of fermented food and high consumption of dietary fiber can promote gut health, physical health, and might even improve mental health. This study aimed to investigate the interrelationship among diet, physical health, and depression.

METHODS

This study used a nationally representative sample (N = 16,572) from the National Health and Nutrition Examination Survey (2011-2018). Dietary information was collected by dietary recall interviews. Depression was assessed by the 9-item Patient Health Questionnaire. Subjective physical health was indicated by self-reported Body Mass Index (BMI). Objective physical health was indicated by BMI measured by trained health technicians. Path analysis was used to test the association between diet and depression, and the mediating roles of self-reported BMI and BMI measured by technicians.

RESULTS

Consumption of probiotic foods and higher intake of fiber were significantly associated with lower levels of depressive symptoms. Both subjective and objective physical health significantly mediated the relationship between variables of diet and mild depressive symptoms. Subjective physical health also significantly mediated the relationship between high intake of dietary fiber and lower likelihood of reporting severe depressive symptoms.

CONCLUSION

Despite being cross-sectional in nature, this study presented evidence that gut-health promoting diets may reduce depressive symptoms through improving physical health. These findings provide preliminary support to diet programs for preventing depression and diet programs as an alternative or supplementary treatment of depression.

Fermented Wheat Germ Alleviates Depression-like Behavior in Rats with Chronic and Unpredictable Mild Stress

Depression is a chronic mental illness with devastating effects on a person's physical and mental health. Studies have reported that food fermentation with probiotics can enrich the nutritional values of food and produce functional microorganisms that can alleviate depression and anxiety. Wheat germ is an inexpensive raw material that is rich in bioactive ingredients. For example, gamma-aminobutyric acid (GABA) is reported to have antidepressant effects. Several studies concluded that Lactobacillus plantarum is a GABA-producing bacteria and can alleviate depression. Herein, fermented wheat germs (FWGs) were used to treat stress-induced depression. FWG was prepared by fermenting wheat germs with Lactobacillus plantarum. The chronic unpredictable mild stress (CUMS) model was established in rats, and these rats were treated with FWG for four weeks to evaluate the effects of FWG in relieving depression. In addition, the study also analyzed the potential anti-depressive mechanism of FWG based on behavioral changes, physiological and biochemical index changes, and intestinal flora changes in depressed rats. The results demonstrated that FWG improved depression-like behaviors and increased neurotransmitter levels in the hippocampus of CUMS model rats. In addition, FWG effectively altered the gut microbiota structure and remodeled the gut microbiota in CUMS rats, restored neurotransmitter levels in depressed rats through the brain-gut axis, and restored amino acid metabolic functions. In conclusion, we suggest that FWG has antidepressant effects, and its potential mechanism may act by restoring the disordered brain-gut axis.

A Comprehensive Review with Future Insights on the Processing and Safety of Fermented Fish and the Associated Changes

As an easily spoiled source of valuable proteins and lipids, fish is preserved by fermentation in many cultures. Over time, diverse types of products have been produced from fish fermentation aside from whole fish, such as fermented fish paste and sauces. The consumption of fermented fish products has been shown to improve both physical and mental health due to the composition of the products. Fermented fish products can be dried prior to the fermentation process and include various additives to enhance the flavours and aid in fermentation. At the same time, the fermentation process and its conditions play a major role in determining the quality and safety of the product as the compositions change biochemically throughout fermentation. Additionally, the necessity of certain microorganisms and challenges in avoiding harmful microbes are reviewed to further optimise fermentation conditions in the future. Although several advanced technologies have emerged to produce better quality products and easier processes, the diversity of processes, ingredients, and products of fermented fish warrants further study, especially for the sake of the consumers' health and safety. In this review, the nutritional, microbial, and sensory characteristics of fermented fish are explored to better understand the health benefits along with the safety challenges introduced by fermented fish products. An exploratory approach of the published literature was conducted to achieve the purpose of this review using numerous books and online databases, including Google Scholar, Web of Science, Scopus, ScienceDirect, and PubMed Central, with the goal of obtaining, compiling, and reconstructing information on a variety of fundamental aspects of fish fermentation. This review explores significant information from all available library databases from 1950 to 2022. This review can assist food industries involved in fermented fish commercialization to efficiently ferment and produce better quality products by easing the fermentation process without risking the health and safety of consumers.

Associations between total dairy, high-fat dairy and low-fat dairy intake, and depressive symptoms: findings from a population-based cross-sectional study

PURPOSE

Evidence on the association between dairy intake and depression is conflicting. Given numerous dietary guidelines recommend the consumption of low-fat dairy products, this study examined associations between total dairy, high-fat dairy, and low-fat dairy intake and the prevalence of elevated depressive symptoms. Associations between dairy products, which differed in both fat content and fermentation status, and depressive symptoms were also explored.

METHODS

This cross-sectional study included 1600 Finnish adults (mean age 63 ± 6 years; 51% female) recruited as part of the Kuopio Ischaemic Heart Disease Risk Factor Study. Dairy intake was assessed using 4-day food records. Elevated depressive symptoms were defined as having a score ≥ 5 on the Diagnostic and Statistical Manual of Mental Disorders-III Depression Scale, and/or regularly using one or more prescription drugs for depressive symptoms.

RESULTS

In total, 166 participants (10.4%) reported having elevated depressive symptoms. Using multivariate logistic regression models, intake in the highest tertile of high-fat dairy products (OR 0.64, 95% CI 0.41-0.998, p trend = 0.04) and high-fat non-fermented dairy products (OR 0.60, 95% CI 0.39-0.92, p trend = 0.02) were associated with reduced odds for having elevated depressive symptoms. Whereas no significant association was observed between intake of total dairy, low-fat dairy, or other dairy products, and depressive symptoms.

CONCLUSION

Higher intake of high-fat dairy and high-fat non-fermented dairy products were associated with reduced odds for having elevated depressive symptoms in middle-aged and older Finnish adults. Given the high global consumption of dairy products, and widespread burden of depression, longitudinal studies that seek to corroborate these findings are required.

The Application of Metagenomics to Study Microbial Communities and Develop Desirable Traits in Fermented Foods

The microbial communities present within fermented foods are diverse and dynamic, producing a variety of metabolites responsible for the fermentation processes, imparting characteristic organoleptic qualities and health-promoting traits, and maintaining microbiological safety of fermented foods. In this context, it is crucial to study these microbial communities to characterise fermented foods and the production processes involved. High Throughput Sequencing (HTS)-based methods such as metagenomics enable microbial community studies through amplicon and shotgun sequencing approaches. As the field constantly develops, sequencing technologies are becoming more accessible, affordable and accurate with a further shift from short read to long read sequencing being observed. Metagenomics is enjoying wide-spread application in fermented food studies and in recent years is also being employed in concert with synthetic biology techniques to help tackle problems with the large amounts of waste generated in the food sector. This review presents an introduction to current sequencing technologies and the benefits of their application in fermented foods.

Novel Candidate Microorganisms for Fermentation Technology: From Potential Benefits to Safety Issues

Fermentation is one of the oldest known production processes and the most technologically valuable in terms of the food industry. In recent years, increasing nutrition and health awareness has also changed what is expected from fermentation technology, and the production of healthier foods has started to come a little more forward rather than increasing the shelf life and organoleptic properties of foods. Therefore, in addition to traditional microorganisms, a new generation of (novel) microorganisms has been discovered and research has shifted to this point. Novel microorganisms are known as either newly isolated genera and species from natural sources or bacterial strains derived from existing bacteria. Although novel microorganisms are mostly studied for their use in novel food production in terms of gut-microbiota modulation, recent innovative food research highlights their fermentative effects and usability, especially in food modifications. Herein, Clostridium butyricum, Bacteroides xylanisolvens, Akkermansia muciniphila, Mycobacterium setense manresensis, and Fructophilic lactic acid bacteria (FLAB) can play key roles in future candidate microorganisms for fermentation technology in foods. However, there is also some confusion about the safety issues related to the use of these novel microorganisms. This review paper focuses on certain novel candidate microorganisms for fermentation technology with a deep view of their functions, benefits, and safety issues.

Choice Experiment Assessment of Consumer Preferences for Yogurt Products Attributes: Evidence from Taiwan

Previous studies on consumer yogurt preferences have mainly focused on added sugar, nutrient content, and health claims, leaving several knowledge gaps that should be filled through in-depth research. In this study, a more complete multi-attribute preference model was developed using the number of probiotic types, type of milk source, presence of edible gels (GEL), and usage of health food labels as the main yogurt attributes. A choice experiment (CE) was then conducted to investigate the relationship between multiple attribute preferences and willingness-to-pay (WTP). A total of 435 valid questionnaires were collected by the convenience sampling method. The results show that (1) respondents highly value the health food label (HEA), followed by the number of probiotic types (PRO); (2) the highest WTP in the conditional logit (CL) model was New Taiwan Dollar (NTD) (USD 10.5 for HEA, and the lowest was NTD 1.0 for 100% milk powder (MLK2); (3) in the random-parameter logit (RPL) model, the highest WTP was NTD 14.6 for HEA, and the lowest was NTD 2.8 for GEL; (4) the most preferred attribute combination of yogurt was “8 or more probiotic types”, “a blend of raw milk and milk powder”, “the absence of edible gels”, “the presence of a health food label”, and “a price premium of NTD 6–10”; (5) married respondents with children were more willing to pay extra for yogurt products with a higher number of probiotic types and a health food label. The results may help the food industry understand and pay attention to consumer needs, which will, in turn, provide a reference for future product development and marketing strategies.