Diet and Anxiety: A Scoping Review.

Anxiety disorders are the most common group of mental disorders. There is mounting evidence demonstrating the importance of nutrition in the development and progression of mental disorders such as depression; however, less is known about the role of nutrition in anxiety disorders. This scoping review sought to systematically map the existing literature on anxiety disorders and nutrition in order to identify associations between dietary factors and anxiety symptoms or disorder prevalence as well as identify gaps and opportunities for further research. The review followed established methodological approaches for scoping reviews. Due to the large volume of results, an online program (Abstrackr) with artificial intelligence features was used. Studies reporting an association between a dietary constituent and anxiety symptoms or disorders were counted and presented in figures. A total of 55,914 unique results were identified. After a full-text review, 1541 articles met criteria for inclusion. Analysis revealed an association between less anxiety and more fruits and vegetables, omega-3 fatty acids, "healthy" dietary patterns, caloric restriction, breakfast consumption, ketogenic diet, broad-spectrum micronutrient supplementation, zinc, magnesium and selenium, probiotics, and a range of phytochemicals. Analysis revealed an association between higher levels of anxiety and high-fat diet, inadequate tryptophan and dietary protein, high intake of sugar and refined carbohydrates, and "unhealthy" dietary patterns. Results are limited by a large percentage of animal and observational studies. Only 10% of intervention studies involved participants with anxiety disorders, limiting the applicability of the findings. High quality intervention studies involving participants with anxiety disorders are warranted.

A systematic review on the effects of Echinacea supplementation on cytokine levels: Is there a role in COVID-19?

COVID-19 is the respiratory illness caused by the novel coronavirus, SARS-CoV-2. Cytokine storm appears to be a factor in COVID-19 mortality. Echinacea species have been used historically for immune modulation. A previous rapid review suggested that Echinacea supplementation may decrease the levels of pro-inflammatory cytokines involved in cytokine storm. The objective of the present systematic review was to identify all research that has assessed changes in levels of cytokines relevant to cytokine storm in response to administration of Echinacea supplementation. The following databases were searched: Medline (Ovid), AMED (Ovid), CINAHL (EBSCO), EMBASE (Ovid). Title and abstract screening, full text screening, and data extraction were completed in duplicate using a piloted extraction template. Risk of bias assessment was completed. Qualitative analysis was used to assess for trends in cytokine level changes. The search identified 279 unique publications. After full text screening, 105 studies met criteria for inclusion including 13 human studies, 24 animal studies, and 71 in vitro or ex vivo studies. The data suggest that Echinacea supplementation may be associated with a decrease in the pro-inflammatory cytokines IL-6, IL-8, and TNF, as well as an increase in the anti-inflammatory cytokine IL-10. The risk of bias in the included studies was generally high. While there is currently no substantive research on the therapeutic effects of Echinacea in the management of either cytokine storm or COVID-19, the present evidence related to the herb's impact on cytokine levels suggests that further research may be warranted in the form of a clinical trial involving patients with COVID-19.

The effect of quercetin on the prevention or treatment of COVID-19 and other respiratory tract infections in humans: A rapid review.

BRIEF OVERVIEW: There is currently insufficient evidence to recommend quercetin supplementation as a therapy for the treatment or prevention of COVID-19. Three human clinical trials with low risk of bias suggest that oral quercetin may have a beneficial effect on the incidence and duration of respiratory tract infections in certain populations; however, further research is needed. VERDICT: Current evidence on the efficacy of quercetin supplementation in the treatment and prevention of COVID-19 is insufficient for its clinical recommendation at this time. Quercetin exhibits both immunomodulatory and antimicrobial effects in preclinical studies; however, only three human clinical trials, each with a low risk of bias rating, were identified in this rapid review. One study reported a decrease in incidence of upper respiratory tract infections following a competitive athletic event. A larger community clinical trial reported a benefit in older, athletic adults only.

The effect of Echinacea spp. on the prevention or treatment of COVID-19 and other respiratory tract infections in humans: A rapid review.

BRIEF OVERVIEW: Current evidence suggests that Echinacea supplementation may decrease the duration and severity of acute respiratory tract infections; however, no studies using Echinacea in the prevention or treatment of conditions similar to COVID-19 have been identified. Few adverse events were reported, suggesting that this herbal therapy is reasonably safe. Because Echinacea can increase immune function, there is a concern that it could worsen over-activation of the immune system in cytokine storm; however, clinical trials show that Echinacea decreases levels of immune molecules involved in cytokine storm. VERDICT: Echinacea supplementation may assist with the symptoms of acute respiratory infections (ARI) and the common cold, particularly when administered at the first sign of infection; however, no studies using Echinacea in the prevention or treatment of conditions similar to COVID-19 have been identified. Previous studies have reported that Echinacea may decrease the severity and/or duration of ARI when taken at the onset of symptoms. The studies reporting benefit used E. purpurea or a combination of E. purpurea and E. angustifolia containing standardized amounts of active constituents.Few adverse events from the use of Echinacea were reported, suggesting that this herbal therapy is reasonably safe. No human trials could be located reporting evidence of cytokine storm when Echinacea was used for up to 4 months.When assessing all human trials which reported changes in cytokine levels in response to Echinacea supplementation, the results were largely consistent with a decrease in the pro-inflammatory cytokines that play a role in the progression of cytokine storm and Acute Respiratory Distress Syndrome (ARDS), factors that play a significant role in the death of COVID-19 patients. While there is currently no research on the therapeutic effects of Echinacea in the management of cytokine storm, this evidence suggests that further research is warranted.