A Possible Antidepressive Effect of Dietary Interventions: Emergent Findings and Research Challenges

The Economics of Treatment for Depression

The global prevalence of depression has risen over the past three decades across all socioeconomic groups and geographic regions, with a particularly rapid increase in prevalence among adolescents (aged 12-17 years) in the United States. Depression imposes large health, economic, and societal costs, including reduced life span and quality of life, medical costs, and reduced educational attainment and workplace productivity. A wide range of treatment modalities for depression are available, but socioeconomic disparities in treatment access are driven by treatment costs, lack of culturally tailored options, stigma, and provider shortages, among other barriers. This review highlights the need for comparative research to better understand treatments' relative efficacy, cost-effectiveness, scalability, and potential heterogeneity in efficacy across socioeconomic groups and country and cultural contexts. To address the growing burden of depression, mental health policy could consider reducing restrictions on the supply of providers, implementing digital interventions, reducing stigma, and promoting healthy lifestyles.

The Power of Psychobiotics in Depression: A Modern Approach through the Microbiota-Gut-Brain Axis: A Literature Review

The microbiota-gut-brain (MGB) axis is a complex communication network linking the gut, microbiota, and brain, influencing various aspects of health and disease. Dysbiosis, a disturbance in the gut microbiome equilibrium, can significantly impact the MGB axis, leading to alterations in microbial composition and function. Emerging evidence highlights the connection between microbiota alterations and neurological and psychiatric disorders, including depression. This review explores the potential of psychobiotics in managing depressive disorders, emphasizing their role in restoring microbial balance and influencing the MGB axis. Psychobiotics exhibit positive effects on the intestinal barrier, immune response, cortisol levels, and the hypothalamic-pituitary-adrenal (HPA) axis. Studies suggest that probiotics may serve as an adjunct therapy for depression, especially in treatment-resistant cases. This review discusses key findings from studies on psychobiotics interventions, emphasizing their impact on the gut-brain axis and mental health. The increasing acceptance of the expanded concept of the MGB axis underscores the importance of microorganisms in mental well-being. As our understanding of the microbiome's role in health and disease grows, probiotics emerge as promising agents for addressing mental health issues, providing new avenues for therapeutic interventions in depressive disorders.

The impact of the Mediterranean diet on alleviating depressive symptoms in adults: a systematic review and meta-analysis of randomized controlled trials

CONTEXT

High adherence to the Mediterranean diet (MD) has been associated with a reduced risk of depression in prospective cohort studies, but whether MD interventions are effective among adults with depression is uncertain.

OBJECTIVE

This study aimed to synthesize findings on the effects of MD interventions on the severity of depressive symptoms in adults with depression.

DATA SOURCES

PubMed, Cochrane CENTRAL, PsycINFO, Scopus, and Web of Science were systematically searched from database inception to March 2023. The Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines and the Cochrane recommendations were followed. We included randomized controlled trials (RCTs) comparing outcomes after MD interventions with outcomes for control conditions in adults with depressive disorders or depressive symptoms.

DATA EXTRACTION

Two authors extracted the data independently. The Sidik-Jonkman estimator, the I2 metric, and the prediction interval were used to estimate between-study heterogeneity. To determine the risk of bias and the certainty of evidence from RCTs, we used the Cochrane Collaboration's Risk of Bias 2 and Grades of Recommendation, Assessment, Development, and Evaluation tools, respectively.

DATA ANALYSIS

In total, 1507 participants (mean age range: 22.0 years-53.3 years) with depression were initially included in the 5 RCTs of this review. Compared with control conditions, MD interventions significantly reduced depressive symptoms among young and middle-aged adults with major depression or mild to moderate depressive symptoms (standardized mean difference: -0.53; 95% confidence interval: -0.90 to -0.16; I2 = 87.1%). The prediction interval ranged from -1.86 to 0.81. The overall risk of bias was within the range of "some concerns" to "high," while the certainty of evidence was low.

CONCLUSION

MD interventions appear to have substantial potential for alleviating depressive symptoms in people experiencing major or mild depression. However, to establish robust recommendations, there remains a need for high-quality, large-scale, and long-term RCTs.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022341895.

The effect of lifestyle interventions on depressive symptom severity in individuals with type-2 diabetes: A meta-analysis of randomized controlled trials

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a severe metabolic condition which is commonly comorbid with depression. Lifestyle factors are involved in the pathophysiology of both conditions; however, the role of lifestyle interventions remains unclear.

OBJECTIVE

The objective of this study is to systematically review the literature on randomized controlled trials evaluating the effect of lifestyle interventions on depressive scores in patients with T2DM.

METHODS

A systematic search was conducted in computerized databases before October 2022. A random-effects model was used to investigate the effect of lifestyle interventions on depression scores and meta-regression was conducted to assess the influence of age and disease onset.

RESULTS

Six trials met the eligibility criteria for inclusion. A statistically significant reduction in depression scores was found for groups receiving lifestyle interventions compared to controls (SMD = -0.49 [95%CI -0.89 to -0.08]; p = 0.0269]). Interventions increased in efficacy with the age of the participants but no significant correlation was found with years since disease onset. Participants in a control group receiving a less intense lifestyle intervention demonstrated improved depression scores when compared to those who received standard care or no intervention at all. Trial design and outcome measurement tools were heterogeneous between studies and limited data on antidepressant use was available which may introduce bias into the results.

CONCLUSION

Lifestyle interventions were effective at improving depressive symptom severity in patients with T2DM.

Exploring the Relationship between Mood Disorders and Coexisting Health Conditions: The Focus on Nutraceuticals

Major depressive disorder and bipolar disorder are the leading causes of global disability. Approximately 50% of patients fail to attain remission, prompting a pronounced focus on the significance of dietary patterns and specific nutrients within the pathophysiology of mood disorders. The connection between chronic diseases and mood disorders follows a bidirectional pattern: physical ailments are interrelated with affective disorders, and, concurrently, mood symptoms often precede chronic diseases and have the potential to worsen their prognosis. Nutraceuticals affect factors that could potentially impact the onset of mood disorders: monoamines and brain-derived neurotrophic factor (BDNF) concentrations, neuroinflammation, oxidative stress, and sleep quality. Furthermore, mood disorders rarely manifest in isolation. Typically, such patients concurrently experience other mental disorders or somatic comorbidities: obesity, hypertension, diabetes, polycystic ovary syndrome (PCOS), etc., where providing nutritional support is also pertinent. To optimize the therapeutic approach for individuals with mood disorders, incorporating nutritional support may not solely ameliorate symptoms stemming directly from the mental condition, but also indirectly through interventions targeting comorbidities.

Dietary Nutrient Deficiencies and Risk of Depression (Review Article 2018-2023)

Depression is classified as one of the most common mental disorders. Its prevalence has recently increased, becoming a growing public health threat. This review focuses on clarifying the role and importance of individual nutrients in the diet and the impact of nutrient deficiencies on the risk of depression. Deficiencies in nutrients such as protein, B vitamins, vitamin D, magnesium, zinc, selenium, iron, calcium, and omega-3 fatty acids have a significant impact on brain and nervous system function, which can affect the appearance of depressive symptoms. However, it is important to remember that diet in itself is not the only factor influencing the risk of or helping to treat depression. There are many other aspects, such as physical activity, sleep, stress management, and social support, that also play an important role in maintaining mental health. The data review observed that most of the available analyses are based on cross-sectional studies. Further studies, including prospective cohort, case-control studies, are recommended to draw more reliable conclusions.

Implications of Dietary Intake and Eating Behaviors for People with Serious Mental Illness: A Qualitative Study

The impact of poor diet quality and nutritional inadequacies on mental health and mental illness has recently gained considerable attention in science. As the opinions and experiences of people living with serious mental illness on dietary issues are unknown, we aimed to understand the role of nutrition in a biopsychosocial approach. In total, 28 semi-structured interviews were conducted with people living with serious mental illness (SMI) in Australia, Germany and Austria, and a generic thematic analysis approach was applied. Four positive (positive effects on the body and mind, therapeutic effects in treating somatic illnesses, pleasure and opportunity for self-efficacy) and three negative (impairment related to mental illness and its treatment, perceived stigma and negative effects on the body and mind) implications of diet were identified. A key issue for most of the participants was the mental burden arising from their body weight. This might indicate that negative implications, such as guilt and stigma, were of primary importance for people with SMI when talking about their dietary behavior. In conclusion, diet-related support is urgently needed for people with SMI. However, especially participants from Germany and Austria reported that this is not yet widely available in mental health settings, leading to hopelessness and resignation.