The association between methylmalonic acid, a biomarker of mitochondrial dysfunction, and cause-specific mortality in Alzheimer's disease and Parkinson's disease

Association between methylmalonic acid and prevalence of depression in US adults: evidence from NHANES 2011-2014

Background: Depression is a prevalent mental disorder with high morbidity and mortality globally. Methylmalonic acid (MMA) is involved in the pathogenesis of numerous diseases. However, it is unclear whether there is an association between MMA and the prevalence of depression.Methods: This study enrolled 7866 US adults from the 2011-2014 survey of the National Health and Nutrition Examination Survey (NHANES). Individuals were categorized into depression group and non-depression group based on Patient's Health Questionnaire-9 (PHQ-9) score. The association between MMA concentrations and prevalence of depression was analysed by multivariate logistic and linear regression, restricted cubic spline regression, and subgroup analysis. Mediation analysis was used to explore the role of inflammation in the relationship between MMA and depression.Results: MMA concentrations were higher in participants with depression than those without depression. There was a positive and linear relationship of MMA concentrations with PHQ-9 score and depression risk, respectively. Moreover, the association was stable in most subgroups. Furthermore, inflammatory factors were positively correlated to MMA concentrations and prevalence of depression. In addition, white blood cell, neutrophil and alkaline phosphatase (ALP) mediated the relationship between MMA and depression.Conclusion: Our findings revealed that there was a linear and positive correlation between MMA and the prevalence of depression in US adults, which might be mediated by inflammation.

Neuroinflammation and Natural Antidepressants: Balancing Fire with Flora

Background/Objectives: Major depressive disorder (MDD) is a major global health concern that is intimately linked to neuroinflammation, oxidative stress, mitochondrial dysfunction, and complicated metabolic abnormalities. Traditional antidepressants frequently fall short, highlighting the urgent need for new, safer, and more acceptable therapeutic techniques. Phytochemicals, i.e., natural antidepressants derived from plants, are emerging as powerful plant-based therapies capable of targeting many pathogenic pathways at the same time. Summary: This narrative review synthesizes evidence from preclinical and clinical studies on the efficacy of phytochemicals such as curcumin, polyphenols, flavonoids, and alkaloids in lowering depressed symptoms. Consistent data show that these substances have neuroprotective, anti-inflammatory, and antioxidant properties, altering neuroimmune interactions, reducing oxidative damage, and improving mitochondrial resilience. Particularly, polyphenols and flavonoids have great therapeutic potential because of their capacity to penetrate the blood-brain barrier, inhibit cytokine activity, and encourage neuroplasticity mediated by brain-derived neurotrophic factor (BDNF). Despite promising results, the heterogeneity in study designs, phytochemical formulations, and patient demographics highlights the importance of thorough, standardized clinical studies. Conclusions: This review identifies phytochemicals as compelling adjuvant or independent therapies in depression treatment, providing multimodal mechanisms and enhanced tolerability. Additional research into improved dosage, pharmacokinetics, long-term safety, and integrative therapy approaches is essential. Using phytotherapeutics could considerably improve holistic and customized depression care, encouraging new research routes in integrative neuroscience and clinical psychiatry.