Zinc as a Neuroprotective Nutrient for COVID-19-Related Neuropsychiatric Manifestations: A Literature Review.

The outbreak of the pandemic associated with Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) led researchers to find new potential treatments, including nonpharmacological molecules such as zinc (Zn2+). Specifically, the use of Zn2+ as a therapy for SARS-CoV-2 infection is based on several findings: 1) the possible role of the anti-inflammatory activity of Zn2+ on the aberrant inflammatory response triggered by COronaVIrus Disease 19 (COVID-19), 2) properties of Zn2+ in modulating the competitive balance between the host and the invading pathogens, and 3) the antiviral activity of Zn2+ on a number of pathogens, including coronaviruses. Furthermore, Zn2+ has been found to play a central role in regulating brain functioning and many disorders have been associated with Zn2+ deficiency, including neurodegenerative diseases, psychiatric disorders, and brain injuries. Within this context, we carried out a narrative review to provide an overview of the evidence relating to the effects of Zn2+ on the immune and nervous systems, and the therapeutic use of such micronutrients in both neurological and infective disorders, with the final goal of elucidating the possible use of Zn2+ as a preventive or therapeutic intervention in COVID-19. Overall, the results from the available evidence showed that, owing to its neuroprotective properties, Zn2+ supplementation could be effective not only on COVID-19-related symptoms but also on virus replication, as well as on COVID-19-related inflammation and neurological damage. However, further clinical trials evaluating the efficacy of Zn2+ as a nonpharmacological treatment of COVID-19 are required to achieve an overall improvement in outcome and prognosis.

The role of vitamin D in bipolar disorder: Epidemiology and influence on disease activity.

BACKGROUND: Although many studies found an association between psychiatric disorders, especially major depressive disorder, and vitamin D deficiency, little is still known about the association between vitamin D and bipolar disorder (BD). Therefore, the present review aims at providing an overview of the available literature exploring the role of vitamin D in BD patients in different phases of the disease. METHODS: From a bibliographic research in PubMed until April 2020, we collected ten original studies that fulfilled our inclusion criteria. RESULTS: No significant differences in vitamin D levels between BD patients and other psychiatric disorders were found by most of the studies. In the majority of the studies, the average values of vitamin D in BD population were sub-threshold for vitamin D deficiency. Moreover, although an association between vitamin D levels and clinical symptomatology was observed in BD patients, it cannot be considered a specific marker of this disorder but a common characteristic shared with other psychiatric disorders, including schizophrenia and major depressive disorder. Finally, vitamin D supplementation was associated with a reduction in both depressive and manic symptoms. LIMITATIONS: Few studies with small and heterogeneous populations. Methodological heterogeneity in terms of vitamin D measurement and threshold. CONCLUSIONS: The results showed that vitamin D status does not differ between BD and other psychiatric conditions. However, given the correlation between vitamin D levels and depressive or manic symptoms, we could hypothesize that an adequate vitamin D status could positively affect the mood balance thanks to its immunomodulatory activity.