Current Trends, Challenges for Research, and Therapeutic Perspectives in Nutritional Psychiatry

"Nutritional interventions in the field of psychiatry have been explored more intensively in the last two decades, but definitive conclusions based on the retrieved data in the literature about the efficacy of this therapeutic approach are difficult to formulate. This observation has multiple explanations, e.g., these therapeutic interventions are very heterogenous, cohort studies usually enroll different psychiatric populations or healthy subjects with minor psychiatric symptoms, nutritional supplements or special diets are commonly recommended as add-ons to the pharmacological interventions (thus making it difficult to differentiate the impact of each therapy on the outcomes), placebo-controlled randomized studies are still very few, etc. Therefore, a narrative review focused on the main challenges reported during the research in the field of nutritional psychiatry (NP) may be useful for clinicians interested in strategies to augment the efficacy of pharmacological treatments or to find new solutions with low risk of adverse events in patients with organic comorbidities or multiple concomitant medications. Data about the efficacy and tolerability of nutritional interventions explored for psychiatric disorders were searched in four electronic databases (PubMed, Cochrane, Clarivate/Web of Science, and EMBASE). Omega-3 polyunsaturated fatty acids supplementation, healthy diet interventions, folate and vitamin B12, S-adenosyl-L-methionine, N-acetyl cysteine, vitamin B1 and B6, vitamin D, minerals, psychobiotics, inositol, and herbal products were the main interventions identified, and their demonstrated efficacy was quite heterogenous, while their tolerability and safety were good. Therefore, NP is a domain of research that may benefit from more good-quality and longer-duration trials, in order to verify the effectiveness of such augmentation strategies to the already validated treatments."