Explore the vast range of titles available.

Depression is a multifaceted condition with diverse underlying causes. Several contributing and inter-related factors such as genetic, nutritional, neurological, physiological, gut-brain-axis, metabolic and psychological stress factors play a role in the pathophysiology of depression. This review aims to highlight the role that nutritional factors play in the aetiology of depression. Secondly, we discuss the biomedical and functional pathology tests which measure these factors, and the current evidence supporting their use. Lastly, we make recommendations on how practitioners can incorporate the latest evidence-based research findings into clinical practice. This review highlights that diet and nutrition greatly affect the pathophysiology of depression. Nutrients influence gene expression, with folate and vitamin B12 playing vital roles in methylation reactions and homocysteine regulation. Nutrients are also involved in the tryptophan/kynurenine pathway and the expression of brain-derived neurotrophic factor (BDNF). Additionally, diet influences the hypothalamic-pituitary-adrenal (HPA) response and the composition and diversity of the gut microbiome, both of which have been implicated in depression. A comprehensive dietary assessment, combined with appropriate evaluation of biochemistry and blood pathology, may help uncover contributing factors to depressive symptoms. By employing such an approach, a more targeted and personalised treatment strategy can be devised, ultimately leading to improved patient outcomes.

Since previous meta-analyses, which were limited only to depression and by a small number of studies available for inclusion at the time of publication, several additional studies have been published assessing the link between ultra-processed food consumption and depression as well as other mental disorders. We aimed to build on previously conducted reviews to synthesise and meta-analyse the contemporary evidence base and clarify the associations between the consumption of ultra-processed food and mental disorders. A total of 17 observational studies were included (n = 385,541); 15 cross-sectional and 2 prospective. Greater ultra-processed food consumption was cross-sectionally associated with increased odds of depressive and anxiety symptoms, both when these outcomes were assessed together (common mental disorder symptoms odds ratio: 1.53, 95%CI 1.43 to 1.63) as well as separately (depressive symptoms odds ratio: 1.44, 95%CI 1.14 to 1.82; and, anxiety symptoms odds ratio: 1.48, 95%CI 1.37 to 1.59). Furthermore, a meta-analysis of prospective studies demonstrated that greater ultra-processed food intake was associated with increased risk of subsequent depression (hazard ratio: 1.22, 95%CI 1.16 to 1.28). While we found evidence for associations between ultra-processed food consumption and adverse mental health, further rigorously designed prospective and experimental studies are needed to better understand causal pathways.

Advanced glycation end products (AGEs) are glycated proteins or lipids formed endogenously in the human body or consumed through diet. Ultra-processed foods and some culinary techniques, such as dry cooking methods, represent the main sources and drivers of dietary AGEs. Tissue accumulation of AGEs has been associated with cellular aging and implicated in various age-related diseases, including type-2 diabetes and cardiovascular disease. The current review summarizes the literature examining the associations between AGEs and neurocognitive and mental health disorders. Studies indicate that elevated circulating AGEs are cross-sectionally associated with poorer cognitive function and longitudinally increase the risk of developing dementia. Additionally, preliminary studies show that higher skin AGE accumulation may be associated with mental disorders, particularly depression and schizophrenia. Potential mechanisms underpinning the effects of AGEs include elevated oxidative stress and neuroinflammation, which are both key pathogenetic mechanisms underlying neurodegeneration and mental disorders. Decreasing dietary intake of AGEs may improve neurological and mental disorder outcomes. However, more sophisticated prospective studies and analytical approaches are required to verify directionality and the extent to which AGEs represent a mediator linking unhealthy dietary patterns with cognitive and mental disorders.

There is mounting interest in the potential efficacy of low carbohydrate and very low carbohydrate ketogenic diets in various neurological and psychiatric disorders. To conduct a systematic review and narrative synthesis of low carbohydrate and ketogenic diets (LC/KD) in adults with mood and anxiety disorders. MEDLINE, Embase, PsycINFO and Cochrane databases were systematically searched for articles from inception to 6 September 2022. Studies that included adults with any mood or anxiety disorder treated with a low carbohydrate or ketogenic intervention, reporting effects on mood or anxiety symptoms were eligible for inclusion. PROSPERO registration CRD42019116367. The search yielded 1377 articles, of which 48 were assessed for full-text eligibility. Twelve heterogeneous studies (stated as ketogenic interventions, albeit with incomplete carbohydrate reporting and measurements of ketosis; diet duration: 2 weeks to 3 years; = 389; age range 19 to 75 years) were included in the final analysis. This included nine case reports, two cohort studies and one observational study. Data quality was variable, with no high-quality evidence identified. Efficacy, adverse effects and discontinuation rates were not systematically reported. There was some evidence for efficacy of ketogenic diets in those with bipolar disorder, schizoaffective disorder and possibly unipolar depression/anxiety. Relapse after discontinuation of the diet was reported in some individuals. Although there is no high-quality evidence of LC/KD efficacy in mood or anxiety disorders, several uncontrolled studies suggest possible beneficial effects. Robust studies are now needed to demonstrate efficacy, to identify clinical groups who may benefit and whether a ketogenic diet (beyond low carbohydrate) is required and to characterise adverse effects and the risk of relapse after diet discontinuation.

Bipolar disorder (BD) is a severe psychiatric illness characterized by recurrent mood episodes and significant psychosocial impairment. Emerging evidence supports a bidirectional link between diet and mental health, with growing interest in nutritional psychiatry. This narrative review examines the psychological and psychiatric impact of diet in BD, focusing on biological mechanisms (gut–brain axis, neuroinflammation, oxidative stress, neurotransmitter synthesis, and HPA axis dysregulation) and the role of specific dietary patterns, including Western, Mediterranean, ketogenic, and anti-inflammatory diets. Key micronutrients such as omega-3 fatty acids, B-vitamins, magnesium, and vitamin D are explored in relation to mood regulation. This review also addresses psychological factors, including emotional eating, disordered eating behaviors, and the symbolic meaning of food in BD. Furthermore, it highlights the integration of nutritional psychoeducation into psychotherapy, the impact of comorbidities (e.g., obesity, metabolic syndrome), and the role of lifestyle factors such as sleep and physical activity. Despite promising findings, current research is limited by methodological heterogeneity. Future perspectives should include interdisciplinary, personalized interventions that incorporate nutritional strategies into standard care for BD.

Disturbances in pro/antioxidant balance emerge as a crucial element in bipolar disorder (BD). Some studies suggest that treatment effects on trace element concentration in BD. This study aimed to identify (a) the changes related to oxidative stress in BD and their relationship with trace elements engaged in pro/antioxidant homeostasis; (b) BD biomarkers using machine learning algorithm classification and regression tree (C&RT) analysis. 62 individuals with BD and 40 healthy individuals (HC) were included in the study. The concentration of pro/antioxidant state and concentration of selenium, zinc, arsenic in blood were assessed. We found a higher concentration of total antioxidant capacity, catalase, advanced oxidation protein products and a lower concentration of 4-hydroxynonenal (4-HNE), glutathione, glutathione peroxidase (GPx) in BD compared to HC. All examined trace elements were lower in the BD group compared to HC. A combination of two variables, 4-HNE (cut-off: ≤ 0.004 uM/mg protein) and GPx (cut-off: ≤ 0.485 U/mg protein), was the most promising markers for separating the BD from the HC. The area under the receiver operating characteristic curve values for C&RT was 90.5%. Disturbances in the pro/antioxidant state and concentration of trace elements of patients with BD may be a target for new therapeutic or diagnostic opportunity of BD biomarkers.

Psychological stress and dietary behavior are interdependent forces that greatly influence mental and physical health. Thus, both what and how we eat impact our well-being. Maladaptive eating patterns, such as eating in response to emotional cues rather than physiological hunger, have become increasingly common amid modern stressors and an ultra-processed food environment. This narrative review synthesizes interdisciplinary findings from nutritional psychiatry, microbiome science, and behavioral nutrition to explore how stress physiology, gut–brain interactions, and dietary quality shape emotional regulation and eating behavior. It highlights mechanisms (e.g., HPA-axis dysregulation, blunted interoception, and inflammatory and epigenetic pathways) and examines the evidence for mindful and intuitive eating; phytochemical-rich, whole-food dietary patterns; and the emerging role of precision nutrition. Trauma-informed approaches, cultural foodways, structural barriers to healthy eating, and clinical implementation strategies (e.g., interprofessional collaboration) are considered in the context of public health equity to support sustainable mental wellness through dietary interventions. Ultimately, restoring a healthy relationship with food positions nutrition not only as sustenance but as a modifiable regulator of affect, cognition, and stress resilience, central to mental and physical well-being.

Considering the multiple benefits of nutraceuticals, and given the growing interest in exploring these effects, understanding their mechanisms and implications in mental well-being and neurological integrity is essential and requires further examination to clarify their therapeutic potential. This narrative review provides a comprehensive overview of recent advances in plant-derived nutraceuticals, particularly regarding their impact on mental health and brain function, by examining their bioactive components, their involvement in neuropsychiatric conditions, their role in neurodegeneration, emerging nutraceuticals with clinical relevance, and gut microbiome interactions with nutraceuticals and phytochemicals. Essential fatty acids, prebiotics, phytochemicals, and nutrients such as amino acids, vitamins, minerals, and omega-3 fatty acids contribute to mood regulation and cognitive function. Nutraceuticals can prevent or slow neurodegeneration by targeting misfolded proteins and modulating oxidative stress, neuroinflammation, mitochondrial dysfunction, and dysregulated signaling pathways. Phytochemicals act as phytopsychobiotics, influencing mental health through gut microbiome modulation and generation of bioactive metabolites. Hypericum and curcumin exert neuroprotective, anti-inflammatory, antioxidant, and antidepressant effects. Ginsenosides promote neuroprotection, partially via gut microbiome-mediated mechanisms. Administration of Ginkgo biloba polysaccharides and lavender essential oil improves neurotransmitter regulation, intestinal barrier integrity, and depressive-like behaviors in preclinical models. Omega-3 polyunsaturated fatty acids, anthocyanins, quercetin, catechins, and chlorogenic acid support neuroprotection and cognitive function via modulation of beneficial gut bacteria, short-chain fatty acid production, anti-inflammatory effects, and serotonin metabolism. The landscape of nutraceuticals offers a diverse range of dietary options with considerable potential to promote mental health and prevent neurodegeneration, but further research is required to elucidate how the gut microbiome may enhance these bioactivities.

Emerging evidence suggests that diet therapy (nutrients, foods and dietary patterns) could be effective as a potential adjunctive treatment option for major depressive disorder. Numerous mechanisms have been proposed, including the role inflammation, oxidative stress, brain-derived neurotrophic factor, the gastrointestinal tract microbiome and tryptophan/serotonin metabolism. Despite known differences in depression characteristics and treatment responses between males and females, there are limited sex-specific studies examining the role of diet in young men specifically. This is important as young men are often reluctant to seek mental health support, so finding treatment strategies which appeal to this demographic is crucial. This brief report provides an overview of the most recent advances in the use of diet for preventing and treating depression in young men, highlighting existing challenges and opportunities for future research. We recommend that clinicians discuss the role of diet with depressed young men, so that diet may be used alongside current treatment options.