Role of vitamin D in COVID-19 and other viral infections

Vaccination and food consumption: association with Post-Acute COVID-19 Syndrome in Brazilian adults (CUME Study)

Background

Post-Acute COVID-19 Syndrome (PACS) is an important sequalae of COVID-19. Then, our objective was to analyze the risk and protective factors for PACS in Brazilian adults participating in the Cohort of Universities of Minas Gerais (CUME Study), with emphasis on COVID-19 vaccination and food consumption.

Methods

In this sub-study, we included 2,065 participants of CUME Study who answered the baseline questionnaire in 2016 or 2018 or 2020 or 2022, and the follow-up COVID-19/PACS-specific questionnaire in 2023. PACS diagnosis was based on self-reporting of continuation or development of new symptoms 3 months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least 2 months with no other explanation. To estimate the risk and protective factors for PACS, hierarchical multivariate statistical analysis was conducted using the Cox regression technique, producing two models: (1) focusing on consumption of macro and micronutrients; (2) focusing on consumption of food groups.

Results

After a median of 5.5 years of follow-up, 54.4% of the participants reported PACS. When we analyzed the consumption of macro and micronutrients, higher intake of proteins (HR: 1.36; 95% CI: 1.06-1.74-4th quartile) and lipids (HR: 1.23; 95% CI: 1.02-1.48-4th quartile) were risk factors for PACS. On the other hand, higher intake of vitamin C (HR: 0.78; 95% CI: 0.64-0.94-4th quartile), vitamin D (HR: 0.81; 95% CI: 0.67-0.99-4th quartile), and zinc (HR: 0.66; 95% CI: 0.52-0.83-4th quartile) were protective factors for the outcome (model 1). When we analyzed the consumption of food groups, higher intake of eggs (HR: 1.59; 95% CI: 1.34-1.89-4th quartile) increased the risk of PACS, whereas, respectively, higher and intermediate consumption of white meat (HR: 0.84; 95% CI: 0.71-1.00-4th quartile) and vegetables (HR: 0.81; 95% CI: 0.67-0.99-2nd quartile; HR: 0.81; 95% CI: 0.67-0.99-3rd quartile) decreased the risk of the outcome (model 2). In both models, pre-infection COVID-19 vaccination was a protective factor for PACS.

Conclusion

A healthy diet, with higher consumption of white meat, vegetables and specific micronutrients (vitamin C, vitamin D, zinc), in parallel with pre-infection COVID-19 vaccination, is essential to reduce the risk of PACS.

Vitamin D: Evidence-Based Health Benefits and Recommendations for Population Guidelines

Vitamin D offers numerous under-recognized health benefits beyond its well-known role in musculoskeletal health. It is vital for extra-renal tissues, prenatal health, brain function, immunity, pregnancy, cancer prevention, and cardiovascular health. Existing guidelines issued by governmental and health organizations are bone-centric and largely overlook the abovementioned extra-skeletal benefits and optimal thresholds for vitamin D. In addition, they rely on randomized controlled trials (RCTs), which seldom show benefits due to high baseline 25-hydroxyvitamin D [25(OH)D] concentrations, moderate supplementation doses, and flawed study designs. This review emphasizes the findings from prospective cohort studies showing that higher 25(OH)D concentrations reduce the risks of major diseases and mortality, including pregnancy and birth outcomes. Serum concentrations > 30 ng/mL (75 nmol/L) significantly lower disease and mortality risks compared to <20 ng/mL. With 25% of the U.S. population and 60% of Central Europeans having levels <20 ng/mL, concentrations should be raised above 30 ng/mL. This is achievable through daily supplementation with 2000 IU/day (50 mcg/day) of vitamin D3, which prevent diseases and deaths. Furthermore, a daily dose between 4000 and 6000 IU of vitamin D3 to achieve serum 25(OH)D levels between 40 and 70 ng/mL would provide greater protection against many adverse health outcomes. Future guidelines and recommendations should integrate the findings from observational prospective cohort studies and well-designed RCTs to improve public health and personalized care.

Impact of vitamin D on COVID-19 and other viral diseases

This editorial aims to elucidate the intricate relationship between vitamin D and viral pathogenesis. It explores the anticipated role of vitamin D as a modulator in the immune response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other viral pathogens. The editorial comments are based on the review article by Engin et al. The potential role of vitamin D in modulating immune responses has been highlighted by several studies, suggesting that it may influence both the risk and severity of infections. Vitamin D receptors are present in immunocompetent cells, which indicates that vitamin D can potentially modulate innate and adaptive immune responses. This context is relevant in the pathophysiology of coronavirus disease 2019 (COVID-19), where the immune response to the virus can significantly impact the disease progression and outcome. The immunomodulatory effects of vitamin D can protect against SARS-CoV-2 infection by enhancing innate and adaptive immune responses. It also maintains the integrity of the body's physical barriers and modulates inflammatory responses, thereby preventing entry and replication of the virus. Many studies have suggested that adequate vitamin D levels help alleviate morbidity and mortality associated with COVID-19. Furthermore, vitamin D supplementation has been linked with a lower risk of severe disease and mortality in COVID-19 patients, particularly in those with a deficiency during seasons with less sunlight exposure.

The Role of Inflammation in the Pathogenesis of Viral Respiratory Infections

Viral respiratory infections (VRIs) are a leading cause of morbidity and mortality worldwide, making them a significant public health concern. During infection, respiratory viruses, including Influenza virus, SARS-CoV-2, and respiratory syncytial virus (RSV), trigger an antiviral immune response, specifically boosting the inflammatory response that plays a critical role in their pathogenesis. The inflammatory response induced by respiratory viruses can be a double-edged sword since it can be initially induced to be antiviral and protective/reparative from virus-induced injuries. Still, it can also be detrimental to host cells and tissues. However, the mechanisms that differentiate the complex crosstalk between favorable host inflammatory responses and harmful inflammatory responses are poorly understood. This review explores the complex interplay between viral pathogens and the host immune response, mainly focusing on the role of inflammation in the pathogenesis of VRIs. We discuss how inflammation can both contain and exacerbate the progression of viral infections, highlighting potential therapeutic targets and emerging drugs for modulating the aberrant inflammatory responses during VRIs.