Vitamine D et virus?

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Evidence Regarding Vitamin D and Risk of COVID-19 and Its Severity
by Joseph Mercola Nutrients 2020, 12(11), 3361;

Vitamin D deficiency co-exists in patients with COVID-19. At this time, dark skin color, increased age, the presence of pre-existing illnesses and vitamin D deficiency are features of severe COVID disease. Of these, only vitamin D deficiency is modifiable. Through its interactions with a multitude of cells, vitamin D may have several ways to reduce the risk of acute respiratory tract infections and COVID-19: reducing the survival and replication of viruses, reducing risk of inflammatory cytokine production, increasing angiotensin-converting enzyme 2 concentrations, and maintaining endothelial integrity.

Fourteen observational studies offer evidence that serum 25-hydroxyvitamin D concentrations are inversely correlated with the incidence or severity of COVID-19. The evidence to date generally satisfies Hill’s criteria for causality in a biological system, namely, strength of association, consistency, temporality, biological gradient, plausibility (e.g., mechanisms), and coherence, although experimental verification is lacking. Thus, the evidence seems strong enough that people and physicians can use or recommend vitamin D supplements to prevent or treat COVID-19 in light of their safety and wide therapeutic window. In view of public health policy, however, results of large-scale vitamin D randomized controlled trials are required and are currently in progress.

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2.14. Other Nutrients That May Augment the Effectiveness of Vitamin D Supplementation

Magnesium supplementation is recommended when taking vitamin D supplements. Magnesium facilitates vitamin D-related processes. All the enzymes that metabolize vitamin D seem to require magnesium, which acts as a cofactor in the enzymatic reactions in the liver and kidneys [148]. The dose of magnesium should be in the range of 250–500 mg/d. Magnesium activates more than 600 enzymes and influences extracellular calcium concentrations [149]. It is essential for the stability of cell function, RNA and DNA synthesis, and cell repair, as well as maintaining the cell’s antioxidant status. Magnesium is an important cofactor for activating a wide range of transporters and enzymes [150,151], many of which involve vitamin D metabolism.
Although vitamin D is likely to be the most important nutrient to optimize COVID-19 prevention, other nutrients, such as magnesium, vitamin K2 and other micronutrients, are also known to impact the immune system and infection risk [152,153,154].

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Traduction de l'étude

Preuve concernant la vitamine D et le risque de COVID-19 et sa gravité
par Joseph Mercola Nutrients 2020, 12 (11), 3361;

Une carence en vitamine D coexiste chez les patients atteints de COVID-19. À l'heure actuelle, la couleur de la peau foncée, l'âge accru, la présence de maladies préexistantes et une carence en vitamine D sont des caractéristiques d'une maladie COVID grave. Parmi ceux-ci, seule une carence en vitamine D est modifiable. Grâce à ses interactions avec une multitude de cellules, la vitamine D peut avoir plusieurs façons de réduire le risque d'infections aiguës des voies respiratoires et de COVID-19: réduire la survie et la réplication des virus, réduire le risque de production de cytokines inflammatoires, augmenter l'enzyme de conversion de l'angiotensine 2 concentrations et le maintien de l’intégrité endothéliale.

Quatorze études d'observation offrent des preuves que les concentrations sériques de 25-hydroxyvitamine D sont inversement corrélées à l'incidence ou à la gravité du COVID-19. Les preuves à ce jour satisfont généralement aux critères de causalité de Hill dans un système biologique, à savoir la force de l'association, la cohérence, la temporalité, le gradient biologique, la plausibilité (par exemple, les mécanismes) et la cohérence, bien que la vérification expérimentale fasse défaut. Ainsi, les preuves semblent suffisamment solides pour que les gens et les médecins puissent utiliser ou recommander des suppléments de vitamine D pour prévenir ou traiter le COVID-19 à la lumière de leur sécurité et de leur large fenêtre thérapeutique. Compte tenu de la politique de santé publique, cependant, les résultats d'essais contrôlés randomisés à grande échelle sur la vitamine D sont nécessaires et sont actuellement en cours

2.14. Autres nutriments qui peuvent augmenter l'efficacité de la supplémentation en vitamine D

Une supplémentation en magnésium est recommandée lors de la prise de suppléments de vitamine D. Le magnésium facilite les processus liés à la vitamine D. Toutes les enzymes qui métabolisent la vitamine D semblent nécessiter du magnésium, qui agit comme cofacteur dans les réactions enzymatiques du foie et des reins [148]. La dose de magnésium doit être comprise entre 250 et 500 mg / j. Le magnésium active plus de 600 enzymes et influence les concentrations extracellulaires de calcium [149]. Il est essentiel pour la stabilité de la fonction cellulaire, la synthèse de l’ARN et de l’ADN et la réparation cellulaire, ainsi que pour le maintien du statut antioxydant de la cellule. Le magnésium est un cofacteur important pour activer une large gamme de transporteurs et d'enzymes [150, 151], dont beaucoup impliquent le métabolisme de la vitamine D.
Bien que la vitamine D soit probablement le nutriment le plus important pour optimiser la prévention du COVID-19, d'autres nutriments, tels que le magnésium, la vitamine K2 et d'autres micronutriments, sont également connus pour avoir un impact sur le système immunitaire et le risque d'infection [152, 153, 154].

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Vitamin D Supplementation Associated to Better Survival in Hospitalized Frail Elderly COVID-19 Patients: The GERIA-COVID Quasi-Experimental Study
by Gaëlle Annweiler Nutrients 2020, 12(11), 3377;

Background. The objective of this quasi-experimental study was to determine whether bolus vitamin D supplementation taken either regularly over the preceding year or after the diagnosis of COVID-19 was effective in improving survival among hospitalized frail elderly COVID-19 patients.

Methods. Seventy-seven patients consecutively hospitalized for COVID-19 in a geriatric unit were included. Intervention groups were participants regularly supplemented with vitamin D over the preceding year (Group 1), and those supplemented with vitamin D after COVID-19 diagnosis (Group 2). The comparator group involved participants having received no vitamin D supplements (Group 3). Outcomes were 14-day mortality and highest (worst) score on the ordinal scale for clinical improvement (OSCI) measured during COVID-19 acute phase. Potential confounders were age, gender, functional abilities, undernutrition, cancer, hypertension, cardiomyopathy, glycated hemoglobin, number of acute health issues at admission, hospital use of antibiotics, corticosteroids, and pharmacological treatments of respiratory disorders.

Results. The three groups (n = 77; mean ± SD, 88 ± 5years; 49% women) were similar at baseline (except for woman proportion, p = 0.02), as were the treatments used for COVID-19. In Group 1 (n = 29), 93.1% of COVID-19 participants survived at day 14, compared to 81.2% survivors in Group 2 (n = 16) (p = 0.33) and 68.7% survivors in Group 3 (n = 32) (p = 0.02). While considering Group 3 as reference (hazard ratio (HR) = 1), the fully-adjusted HR for 14-day mortality was HR = 0.07 (p = 0.017) for Group 1 and HR = 0.37 (p = 0.28) for Group 2. Group 1 had longer survival time than Group 3 (log-rank p = 0.015), although there was no difference between Groups 2 and 3 (log-rank p = 0.32). Group 1, but not Group 2 (p = 0.40), was associated with lower risk of OSCI score ≥5 compared to Group 3 (odds ratio = 0.08, p= 0.03).

Conclusions. Regular bolus vitamin D supplementation was associated with less severe COVID-19 and better survival in frail elderly.

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“Group 1” was defined as all COVID-19 patients who had received oral boluses of vitamin D
supplements over the preceding year. Bolus included the doses of 50,000 IU vitamin D3 per month,
or the doses of 80,000 IU or 100,000 IU vitamin D3 every 2−3 months. None received D2 or
intramuscular supplements, and no patient in Group 1 received additional supplements following
the diagnosis of COVID-19.
“Group 2” was defined as the COVID-19 patients usually not supplemented with vitamin D, but
who received an oral supplement of 80,000 IU vitamin D3 within a few hours of the diagnosis of
COVID-19.

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Malheureusement ou heureusement, le nombre de clics que reçoit une étude, ça peut faire la différence... donc clique et partage le lien de l'étude (pas mon poste) https://www.mdpi.com/2072-6643/12/11/3377

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Donc y’a une sérieuse diminution dans le groupe 1?

Si c’est bien ça , ça commence à faire beaucoup d’éléments en faveur de vit.d contre la covid

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Vitamin D Status in Hospitalized Patients With SARS-CoV-2 Infection
José L Hernández, The Journal of Clinical Endocrinology & Metabolism, 27 October 2020

Background
The role of vitamin D status in COVID-19 patients is a matter of debate.

Objectives
To assess serum 25-hydroxyvitamin D (25OHD) levels in hospitalized patients with COVID-19 and to analyze the possible influence of vitamin D status on disease severity.

Methods
Retrospective case-control study of 216 COVID-19 patients and 197 population-based controls. Serum 25OHD levels were measured in both groups. Besides, the association of serum 25OHD levels with COVID-19 severity (admission to the Intensive Care Unit, requirements for mechanical ventilation, or mortality) was also evaluated.

Results
Of the 216 patients, 19 were on vitamin D supplements and were analyzed separately. In COVID-19 patients, mean±SD 25OHD levels were 13.8±7.2 ng/ml, compared to 20.9±7.4 ng/ml in controls (p<0.0001). 25OHD values were lower in men than in women. Vitamin D deficiency was found in 82.2% of COVID-19 cases and 47.2% of population-based controls (p<0.0001). 25OHD inversely correlate to serum ferritin (p=0.013) and D-dimer levels (p=0.027). Vitamin D-deficient COVID-19 patients had a greater prevalence of hypertension and cardiovascular diseases, raised serum ferritin and troponin levels, as well as a longer length of hospital stay than those with serum 25OHD levels ≥20 ng/ml. No causal relationship was found between vitamin D deficiency and COVID-19 severity as a combined endpoint or as its separate components.

Conclusions
25OHD levels are lower in hospitalized COVID-19 patients compared to population-based controls and these patients had a higher prevalence of deficiency. We did not find any relationship between vitamin D concentrations or vitamin deficiency and the severity of the disease.