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Ultra-Processed Food Consumption and Mental Health: A Systematic Review and Meta-Analysis of Observational Studies.
Lane, MM, Gamage, E, Travica, N, Dissanayaka, T, Ashtree, DN, Gauci, S, Lotfaliany, M, O'Neil, A, Jacka, FN, Marx, W
Nutrients. 2022;14(13)
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Poor dietary quality is well established as a potentially modifiable risk factor for mental disorders. The NOVA food classification system was recently developed to enable the categorisation of food items based on distinctive levels of processing. The aim of this study was to synthesise and provide quantitative analyses of the most up-to-date evidence assessing associations between consumption of ultra-processed food, as defined by the NOVA food classification system, and mental disorders. This study is systematic review and meta-analysis of 17 studies with a total of 385,541 participants. The studies were 15 cross-sectional and 2 prospectively designed studies. Results show that ultra-processed food consumption is bidirectionally associated with adverse mental health. In fact, greater intake of ultra-processed food was associated with increased odds of depressive and anxiety symptoms, both when these outcomes were assessed together as well as separately. Authors conclude that further prospective and experimental studies are required to better determine directionality and causality and ensure that global preventative and treatment strategies are efficacious and appropriate.
Abstract
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.
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The Dose-Response Associations of Sugar-Sweetened Beverage Intake with the Risk of Stroke, Depression, Cancer, and Cause-Specific Mortality: A Systematic Review and Meta-Analysis of Prospective Studies.
Wang, Y, Zhao, R, Wang, B, Zhao, C, Zhu, B, Tian, X
Nutrients. 2022;14(4)
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The consumption of sugar-sweetened beverages is high in today's society, which may lead to weight gain, inflammation, and a number of obesity-associated diseases. The objective of this systematic review and meta-analysis was to investigate the associations and causal links between the consumption of sugar-sweetened beverages and cancer, stroke, depression, and cause-specific mortality. Consumption of sugar-sweetened beverages significantly increased the risk of cancer, strokes, depression, and cause-specific mortality when compared with the consumption of low or no-sugar-sweetened beverages. As little as a 250ml increment of sugar-sweetened beverages was associated with an increase in risk. Consumption of sugar-sweetened beverages increases the risk of ischemic stroke by 10%, CVD-caused mortality by 13%, and cancer-caused mortality by 6.0% compared to those who consume less or no sugar-sweetened beverages. These findings can be used by healthcare professionals to understand the clinical significance of intervention strategies that reduce the consumption of sugar-sweetened beverages. It is imperative to conduct additional robust studies as there is an insufficient amount of evidence at present to establish a causal connection between the consumption of sugary beverages and the risk of depression, stroke, cancer, and cause-specific mortality.
Abstract
The associations between sugar-sweetened beverage (SSB) consumption and the risk of stroke, depression, cancer, and cause-specific mortality have not been determined, and the quantitative aspects of this link remain unclear. This meta-analysis therefore conducted a systematic review and dose-response analysis to determine their causal links. The database searches were conducted in PubMed, Cochrane library, Embase, Web of Science up to 10 November 2021. The intervention effects were evaluated by relative risk (RR) with 95% confidences (CI). Thirty-two articles met the inclusion criteria. Higher levels of SSB consumption significantly increased the risk of stroke (RR 1.12, 95% CI 1.03-1.23), depression (1.25, 1.11-1.41), cancer (1.10, 1.03-1.17), and all-cause mortality (1.08, 1.05-1.11) compared with none or lower SSB intake. The associations were dose-dependent, with per 250 mL increment of SSB intake daily increasing the risk of stroke, depression, cancer, and all-cause mortality by RR 1.09 (1.03-1.15), 1.08 (1.06-1.10), 1.17 (1.04-1.32), and 1.07 (1.03-1.11), respectively. The link was curved for depression and cancer risk (pnon-linear < 0.05). Subgroup analysis suggested that higher SSB intake increased ischemic stroke by 10%, CVD-caused mortality by 13%, and cancer-caused mortality by 6.0% than none or lower SSB consumption. It is suggested that SSB accounts for a leading risk factor of stroke, depression, cancer, and mortality, and that the risk rises in parallel with the increment of SSB intake (and is affected by participant characteristics).
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Effectiveness of Probiotic, Prebiotic, and Synbiotic Supplementation to Improve Perinatal Mental Health in Mothers: A Systematic Review and Meta-Analysis.
Desai, V, Kozyrskyj, AL, Lau, S, Sanni, O, Dennett, L, Walter, J, Ospina, MB
Frontiers in psychiatry. 2021;12:622181
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Maternal mental health problems in the perinatal period are a global public health challenge. As many as one in five women develop depression and/or anxiety in the postpartum period, making them the most common complications of pregnancy and delivery. The aim of this study was to evaluate the evidence on the administration of prebiotic, probiotic, and/or synbiotic supplements during pregnancy to reduce the risk of mental health problems in the perinatal period. This study is a systemic review and meta-analysis of four studies of which three where included in the qualitative and quantitative synthesis. Results indicate limited evidence about the effectiveness of probiotics administered during pregnancy to reduce the risk of maternal mental health disorders and highlighted the lack of evidence on prebiotics and synbiotics supplementation to inform their use for similar purposes. Authors conclude that there is the need for future trials targeting microbiota interventions that test probiotic/prebiotic/synbiotic interventions that redress specific dysbioses in pregnancy gut microbiota that arise from poor mental health.
Abstract
Introduction: There is an emerging interest in modulating the gut microbiota to target the gut-brain axis and improve maternal mental health in the perinatal period. This systematic review evaluated the effectiveness of prebiotics, probiotics, and synbiotics supplementation during pregnancy to reduce the risk of maternal mental health problems in the perinatal period. Methods: Electronic biomedical databases and clinical trial registries were searched from database inception through August 2020 to identify randomized controlled clinical trials (RCTs) evaluating the effect of probiotic, prebiotic, or synbiotic supplements administered to women during pregnancy on measures of perinatal depression, anxiety, and other mental health outcomes. Study selection, risk of bias appraisal, and data extraction were independently performed by two reviewers. Pooled mean differences (MD) and odds ratios (pOR) with 95% confidence intervals (CI) were calculated in random-effects meta-analyses for the outcomes of interest in the review. Results: From 3,868 studies identified through the search strategy, three RCTs of low risk of bias involving 713 participants were included, all three testing probiotics. There were no differences between probiotics and control groups in the mean depression scores (MD -0.46; 95% CI -2.16, 1.25) at end of follow-up. Although statistical significance was not achieved, probiotics showed an advantage in the proportion of participants scoring below an established cut-off for depression (pOR 0.68; 95% CI 0.43, 1.07). Compared to placebo, probiotics in pregnancy reduced anxiety symptoms (MD -0.99; 95% CI -1.80, -0.18); however, this advantage was not translated in a reduction in the proportion of participants scoring above an established cut-off for anxiety (pOR 0.65; 95% CI 0.23, 1.85). There were no differences between probiotics and control groups in global mental health scores at end of follow-up (MD 1.09; 95% CI -2.04, 4.22). Conclusion: There is limited but promising evidence about the effectiveness of probiotics during pregnancy to reduce anxiety symptoms and reduce the proportion of women scoring ABOVE a cut-off depression score. There is a lack of RCT evidence supporting prebiotics and synbiotics supplementation for similar purposes in the perinatal period. More research is needed before prebiotics, probiotics, and synbiotics are recommended to support maternal mental health and well-being in the perinatal period. Systematic Review Registration: PROSPERO, CRD42019137158.
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Consumption of ultra-processed foods and health status: a systematic review and meta-analysis.
Pagliai, G, Dinu, M, Madarena, MP, Bonaccio, M, Iacoviello, L, Sofi, F
The British journal of nutrition. 2021;125(3):308-318
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Ultra-processed foods (UPF) are, according to the NOVA classification, “formulations of ingredients, mostly for industrial use only, derived from a series of industrial processes”. UPF represents an important and growing part of the world’s food supply. The aim of this study was to assess the relationship between UPF consumption as defined by NOVA and health status. This study is systematic review with meta-analysis of all the cross-sectional and cohort studies published to-date. At the end of the selection process, twenty-three articles were included in the qualitative analysis and nineteen in the quantitative analysis. Results indicate the possible association between high UPF consumption, worse cardiometabolic risk profile (reported by an increased risk of overweight/obesity, elevated waist circumference, reduced high-density lipoprotein-cholesterol levels and increased risk of the metabolic syndrome), and greater risk of all-cause mortality, cardiovascular disease, cerebrovascular disease and depression. Authors conclude that their findings have important public health implications, especially for food policymakers who should discourage the consumption of UPF and promote fresh and minimally processed foods to improve health status.
Abstract
Increasing evidence suggests that high consumption of ultra-processed foods (UPF) is associated with an increase in non-communicable diseases, overweight and obesity. The present study systematically reviewed all observational studies that investigated the association between UPF consumption and health status. A comprehensive search of MEDLINE, Embase, Scopus, Web of Science and Google Scholar was conducted, and reference lists of included articles were checked. Only cross-sectional and prospective cohort studies were included. At the end of the selection process, twenty-three studies (ten cross-sectional and thirteen prospective cohort studies) were included in the systematic review. As regards the cross-sectional studies, the highest UPF consumption was associated with a significant increase in the risk of overweight/obesity (+39 %), high waist circumference (+39 %), low HDL-cholesterol levels (+102 %) and the metabolic syndrome (+79 %), while no significant associations with hypertension, hyperglycaemia or hypertriacylglycerolaemia were observed. For prospective cohort studies evaluating a total population of 183 491 participants followed for a period ranging from 3·5 to 19 years, highest UPF consumption was found to be associated with increased risk of all-cause mortality in five studies (risk ratio (RR) 1·25, 95 % CI 1·14, 1·37; P < 0·00001), increased risk of CVD in three studies (RR 1·29, 95 % CI 1·12, 1·48; P = 0·0003), cerebrovascular disease in two studies (RR 1·34, 95 % CI 1·07, 1·68; P = 0·01) and depression in two studies (RR 1·20, 95 % CI 1·03, 1·40; P = 0·02). In conclusion, increased UPF consumption was associated, although in a limited number of studies, with a worse cardiometabolic risk profile and a higher risk of CVD, cerebrovascular disease, depression and all-cause mortality.
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Gluten and FODMAPs Relationship with Mental Disorders: Systematic Review.
Aranburu, E, Matias, S, Simón, E, Larretxi, I, Martínez, O, Bustamante, MÁ, Fernández-Gil, MDP, Miranda, J
Nutrients. 2021;13(6)
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There is growing evidence that gluten and FODMAPs, such as fermentable oligosaccharides, disaccharides, monosaccharides and polyols, can cause gastrointestinal symptoms, inflammation, and immune responses in patients with celiac disease and irritable bowel syndrome. In addition, a high intake of gluten and FODMAPs may also be associated with neurological and psychiatric disorders. Thirteen studies were included in this systematic review to examine the relationship between gluten and FODMAP consumption and illnesses affecting the central nervous system. In addition, the studies examined the effects of potential dietary strategies that consider gluten and FODMAP intake on mental disorders, anxiety, depression, schizophrenia, Alzheimer’s disease, and autism spectrum disorders. Several possible mechanisms identified in this systematic review could contribute to neurological and psychiatric disorders, including the release of proinflammatory cytokines, immune responses, gut dysbiosis, intestinal permeability, and interactions between the gut-brain axis. In patients with fibromyalgia, celiac disease, and irritable bowel syndrome, avoiding or limiting gluten may reduce depression, anxiety, and cognitive impairment. However, the effects of a low-FODMAP diet on the central nervous system are inconclusive. There is some evidence that gluten-free diets can improve cognition in schizophrenia patients. In addition, those with autism spectrum disorders may benefit from a gluten-free diet and a low-FODMAP diet. Further robust research is required to evaluate the beneficial effects of interventions that avoid or restrict the consumption of foods high in FODMAPs and gluten. However, healthcare professionals can use the results of this systematic review to understand the potential benefits of therapeutic interventions that consider the intake of FODMAPs and gluten on illnesses affecting the central nervous system and their possible mechanisms of action.
Abstract
Nowadays, gluten and FODMAP food components (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) are increasingly studied due to their possible relation with extraintestinal-associated conditions. In recent years, gluten-free diets (GFD) and low-FODMAP diets (LFD) are becoming more popular not only in order to avoid the food components that cause intolerances or allergies in some people, but also due to the direct influence of marketing movements or diet trends on feeding habits. Likewise, neurological and psychiatric diseases are currently of increasing importance in developed countries. For this reason, a bibliographic systematic review has been carried out to analyse whether there is a pathophysiological relationship between the dietary intake of gluten or FODMAPs with mental disorders. This review collects 13 clinical and randomized controlled trials, based on the PRISMA statement, which have been published in the last ten years. Based on these results, limiting or ruling out gluten or FODMAPs in the diet might be beneficial for symptoms such as depression, anxiety (7 out of 7 articles found any positive effect), or cognition deficiency (improvements in several cognition test measurements in one trial), and to a lesser extent for schizophrenia and the autism spectrum. Nevertheless, further studies are needed to obtain completely reliable conclusions.
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The Role of Bacteria and Its Derived Metabolites in Chronic Pain and Depression: Recent Findings and Research Progress.
Li, S, Hua, D, Wang, Q, Yang, L, Wang, X, Luo, A, Yang, C
The international journal of neuropsychopharmacology. 2020;23(1):26-41
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Depression is closely associated with chronic pain yet the connection between these comorbidities is ambiguous. Recent studies have shown alterations in the gut microbiome may contribute to cognitive dysfunction via the microbiota-gut-brain axis. The aim of this systematic review is to summarize the existing evidence of the role of the gut microbiome in chronic pain and depression and explore potential mechanisms of gut dysbiosis in the development of these conditions. This review found metabolic products from the gut microbiota can mediate neuro-inflammation and neuro-immunity pathways in pain and depression, and that dysbiosis in the gut may contribute to the cause of chronic pain and depression. The authors conclude the metabolic products from the gut bacteria offer new insights to the connection between the gut microbiota and mechanisms of pain and depression, while showing potential as a therapeutic target.
Abstract
BACKGROUND Chronic pain is frequently comorbid with depression in clinical practice. Recently, alterations in gut microbiota and metabolites derived therefrom have been found to potentially contribute to abnormal behaviors and cognitive dysfunction via the "microbiota-gut-brain" axis. METHODS PubMed was searched and we selected relevant studies before October 1, 2019. The search keyword string included "pain OR chronic pain" AND "gut microbiota OR metabolites"; "depression OR depressive disorder" AND "gut microbiota OR metabolites". We also searched the reference lists of key articles manually. RESULTS This review systematically summarized the recent evidence of gut microbiota and metabolites in chronic pain and depression in animal and human studies. The results showed the pathogenesis and therapeutics of chronic pain and depression might be partially due to gut microbiota dysbiosis. Importantly, bacteria-derived metabolites, including short-chain fatty acids, tryptophan-derived metabolites, and secondary bile acids, offer new insights into the potential linkage between key triggers in gut microbiota and potential mechanisms of depression. CONCLUSION Studying gut microbiota and its metabolites has contributed to the understanding of comorbidity of chronic pain and depression. Consequently, modulating dietary structures or supplementation of specific bacteria may be an available strategy for treating chronic pain and depression.
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Consumption of ultra-processed foods and health outcomes: a systematic review of epidemiological studies.
Chen, X, Zhang, Z, Yang, H, Qiu, P, Wang, H, Wang, F, Zhao, Q, Fang, J, Nie, J
Nutrition journal. 2020;19(1):86
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Unhealthy diets are recognized as a major determinant of the occurrence of non-communicable diseases (NCDs). The aim of this study was to summarize the evidence for the association between ultra-processed food (UPFs) consumption and health outcomes. This study is a systemic review of 20 published epidemiological studies (12 cohort and 8 cross-sectional studies), with a total of 334,114 participants and 10 diseases. Results indicate a positive association between UPFs consumption and risk of all-cause mortality, overall cardiovascular diseases, coronary heart diseases, cerebrovascular diseases, hypertension, metabolic syndrome, overweight and obesity, depression, irritable bowel syndrome, overall cancer, postmenopausal breast cancer, gestational obesity, adolescent asthma and wheezing, and frailty. However, on the contrary, there was not an obvious association with cardiovascular disease mortality, prostate and colorectal cancer, gestational diabetes mellitus and gestational overweight. Authors conclude that their findings encouraged a decrease in UPFs consumption and an increase in the proportion of unprocessed or minimally processed foods, such as fruits and vegetables.
Abstract
BACKGROUND Consumption of ultra-processed foods (UPFs) plays a potential role in the development of obesity and other diet-related noncommunicable diseases (NCDs), but no studies have systematically focused on this. This study aimed to summarize the evidence for the association between UPFs consumption and health outcomes. METHODS A comprehensive search was conducted in PubMed, Embase, and Web of Science to identify all relevant studies. Epidemiological studies were included, and identified studies were evaluated for risk of bias.A narrative review of the synthesized findings was provided to assess the association between UPFs consumption and health outcomes. RESULTS 20 studies (12 cohort and 8 cross-sectional studies) were included in the analysis, with a total of 334,114 participants and 10 health outcomes. In a narrative review, high UPFs consumption was obviously associated with an increased risk of all-cause mortality, overall cardiovascular diseases, coronary heart diseases, cerebrovascular diseases, hypertension, metabolic syndrome, overweight and obesity, depression, irritable bowel syndrome, overall cancer, postmenopausal breast cancer, gestational obesity, adolescent asthma and wheezing, and frailty. It showed no significant association with cardiovascular disease mortality, prostate and colorectal cancers, gestational diabetes mellitus and gestational overweight. CONCLUSIONS This study indicated a positive association between UPFs consumption and risk of several health outcomes. Large-scale prospective designed studies are needed to confirm our findings.
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Use of Meditation and Cognitive Behavioral Therapies for the Treatment of Stress, Depression and Anxiety in Students. A Systematic Review and Meta-Analysis.
González-Valero, G, Zurita-Ortega, F, Ubago-Jiménez, JL, Puertas-Molero, P
International journal of environmental research and public health. 2019;16(22)
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Research in the field of the mind is increasing, with students becoming key objects of study in the field of social sciences and health. The main aim of this study was to review the scientific literature in order to analyze the effect produced by cognitive-behavioural programs and meditation strategies on stress, anxiety, and depression in students. A secondary aim was to identify the determinants of treatment success. This study is a systemic review and meta-analysis of 34 articles which included 3296 participating students. A total of 22 effect sizes were calculated for stress treatment, 28 for anxiety and 28 for depression. Results show that interventions based on cognitive-behavioural programs, self-reflection, and mindfulness-based approaches produce satisfactory and significant results in relation to the reduction of stress, anxiety, and depression in students. Furthermore, taking into consideration the theoretical foundations of the studies analysed, meditation (mindfulness, yoga and tai chi), muscle relaxation and breathing, coaching, and cognitive-behavioural therapy are strategies that have shown effectiveness in improving mental health. Authors conclude that it is essential to focus attention on how to improve the mental health of students, including an increase in the number of interventions in the classroom.
Abstract
The prevalence of mental health problems within students due to high academic demands and learning difficulties is a current challenge the field of education. The aim of this study is to review the scientific literature in order to analyze the effect produced by cognitive-behavioral programs and meditation strategies on stress, anxiety, and depression in students. A further aim is to identify the determinants of treatment success. The bibliographic search was carried out using Web of Science, specifically in the categories of "Education and Educational Research" and "Psychology", obtaining a sample of 122 articles published between 2007 and 2018. Studies were included which had a pre-experimental or quasi-experimental design and included pre-test and post-test phases. Following application of inclusion criteria, 34 articles were selected for inclusion in a meta-analysis of the random effects of each variable. This obtained an average effect size of -0.41 for stress, -0.37 for anxiety, and -0.30 for depression. Three moderating variables were analyzed, with significant correlations being found for the type of treatment relating to stress (Q = 11.01, df = 2, p = 0.004, R2 = 0.294) and depression (Q = 6.14, df = 2, p = 0.048; R2 = 0.436). The stage of education of the individuals was also found to impact upon anxiety intervention success (Q = 13.093 df = 2, p = 0.0009, R2 = 0.196). Interventions mainly addressed the importance of meditation strategies, mindfulness programs, and cognitive-behavioral therapy to reduce stress, anxiety, and depression in students. This supports the need to increase research at an early age, considering the treatment of mental health as a key factor influencing academic performance and quality of life.
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Key Risk Factors Affecting Farmers' Mental Health: A Systematic Review.
Daghagh Yazd, S, Wheeler, SA, Zuo, A
International journal of environmental research and public health. 2019;16(23)
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The prevalence of psychological stress among farmers and farm workers is greater than that of non-farmers. The mental health of farmers can be affected by several factors, including pesticide exposure, financial problems, climate issues, and poor physical health. A total of 167 studies are included in this systematic review incorporating data from the studies conducted in 34 countries, including the United Kingdom, the United States and Australia. There is a need for risk assessment that influences farmers' mental health, according to this systematic review. There is a need for more robust studies to evaluate the impact of climate change and pesticide exposure on farmers' mental health and to determine which strategies can be used to help them find therapies. Using the results of this systematic review, healthcare professionals can raise awareness about mental health issues and assist farmers in identifying the symptoms, allowing them to seek help.
Abstract
Recently, concern has increased globally over farmers' mental health issues. We present a systematic review of the outcomes, locations, study designs, and methods of current studies on farmers' mental health. In particular, this review aims to fill an important gap in understanding of the potential key risk factors affecting farmers' mental health around the world. 167 articles on farmer mental health were included in a final systematic review using a standardized electronic literature search strategy and PRISMA guidelines. The four most-cited influences on farmers' mental health in the reviewed literature respectively were pesticide exposure, financial difficulties, climate variabilities/drought, and poor physical health/past injuries. The majority of studies were from developed countries, most specifically from the United States, Australia, and the United Kingdom. Comparative studies on the mental health of farmers and other occupational workers showed mixed results, with a larger portion identifying that psychological health disturbances were more common in farmers and farm-workers. Knowledge of farmer psychological disorder risk factors and its impacts are essential for reducing the burden of mental illness. Further research will be required on climate change impacts, developing country farmers' mental health, and information on how to reduce help-seeking barriers amongst farmers.
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Mood Disorders and Gluten: It's Not All in Your Mind! A Systematic Review with Meta-Analysis.
Busby, E, Bold, J, Fellows, L, Rostami, K
Nutrients. 2018;10(11)
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Gluten is a protein found in grains such as wheat, barley and rye. For some people, gluten can cause serious health issues such as coeliac disease (CD). A growing body of research suggests that mood symptoms are associated with gluten-related disorders. The objective of this systematic review and meta-analysis was to establish whether a relationship exists between mood and gluten consumption. 13 studies were included in the meta-analysis. A gluten-free diet (GFD) significantly reduced depressive symptoms in 953 participants overall. Subgroup analyses revealed no difference in effect on mood between those with and without diagnosed CD or between those with a genetic predisposition to CD. In patients diagnosed with classical CD, a GFD resulted in a statistically significant reduction in mood symptoms, whereas the effect for silent CD patients was not significant. The authors concluded that gluten elimination may represent an effective treatment strategy for mood disorders in individuals with gluten-related disorders. Future studies should focus on gluten and mood in participants without a gut-related disorder, for example, in a population sample with depression. Finally, the level of support available to help a patient in maintaining a GFD diet over time should be carefully considered when recommending a GFD in practice.
Abstract
Gluten elimination may represent an effective treatment strategy for mood disorders in individuals with gluten-related disorders. However, the directionality of the relationship remains unclear. We performed a systematic review of prospective studies for effects of gluten on mood symptoms in patients with or without gluten-related disorders. Six electronic databases (CINAHL, PsycINFO, Medline, Web of Science, Scopus and Cochrane Library) were searched, from inception to 8 August 2018, for prospective studies published in English. Meta-analyses with random-effects were performed. Three randomised-controlled trials and 10 longitudinal studies comprising 1139 participants fit the inclusion criteria. A gluten-free diet (GFD) significantly improved pooled depressive symptom scores in GFD-treated patients (Standardised Mean Difference (SMD) -0.37, 95% confidence interval (CI) -0.55 to -0.20; p < 0.0001), with no difference in mean scores between patients and healthy controls after one year (SMD 0.01, 95% CI -0.18 to 0.20, p = 0.94). There was a tendency towards worsening symptoms for non-coeliac gluten sensitive patients during a blinded gluten challenge vs. placebo (SMD 0.21, 95% CI -0.58 to 0.15; p = 0.25). Our review supports the association between mood disorders and gluten intake in susceptible individuals. The effects of a GFD on mood in subjects without gluten-related disorders should be considered in future research.