2026 Volume 2 Issue 1 Pages 245-277
Background: Patients presenting to mental health services with depression, fatigue, insomnia, irritability, or cognitive complaints frequently have concurrent nutritional and physical contributors that may be overlo oked by standard diagnostic assessment. These contributors include insufficiency of iron, zinc, magnesiu m, vitamin D, or B vitamins, glycaemic instability, gut dysbiosis, and low-grade inflammation.
Objective: This review presents the Okudaira-style checklist comprising ten clinical domains and 150 item s, designed to capture nutritional and physical factors during the clinical interview and to provide an evide nce-informed bridge to laboratory testing, and critically appraises the underlying biochemical mechanisms and clinical evidence.
Main Text: Each domain contrasts upstream factors (dietary and lifestyle background) with downstream p hysical signs. Mechanistic pathways include micronutrient cofactors for monoamine synthesis, mitochondr ial energy metabolism, neuroinflammation, the gut-brain axis, and hypothalamic-pituitary-adrenal regulati on; established findings are deliberately distinguished from hypotheses. For dietary patterns and selected n utrients, intervention trials and meta-analyses exist, but effect sizes are generally modest, effects are most e vident under baseline deficiency, and observational associations must not be conflated with causal treatme nt effects. Notably, correction of a biomarker does not necessarily translate into symptomatic improvemen t.
Conclusion: The checklist is not a diagnostic instrument but a triage aid for detecting potentially treatable contributors, intended to complement rather than replace standard psychiatric care. Screening for iron defic iency and attention to overall diet quality are reasonable at present, whereas the efficacy of many specific i nterventions remains unconfirmed and should not be overstated. The instrument should be used within inte rprofessional collaboration, and prospective studies to validate its psychometric properties and to evaluate t he prognostic impact of nutritional interventions are warranted.
