The effects of vitamin D on acute viral respiratory infections: A rapid review

Abstract

Brief overview Current evidence suggests vitamin D replacement may reduce risk for acute respiratory tract infections (ARTI) in people with deficiency or insufficiency, although the effects of supplementation on incidence and severity of ARTI in the general population remain unknown. Oral vitamin D supplemzentation taken at routine doses appears to be generally safe and well tolerated. Verdict Current experimental evidence remains inconclusive regarding the effects of vitamin D supplementation in the general population for the prevention and treatment of acute respiratory tract infections (ARTI). There is also insufficient evidence to draw conclusions regarding the impact of vitamin D supplementation on the severity or duration of ARTI, nor on outcomes related to lung injury or hospitalization from ARTI. Based on this rapid review, sources of significant heterogeneity in published clinical trials include: differences study populations, inconsistent assessment of serum status at baseline, dosing variability, varying routes of administration, and/or inconsistent definitions of outcome measures. Experimental evidence and observations in large cohorts are generally consistent that vitamin D deficiency (<50 nmol/L [<20 ng/mL]) and insufficiency (<75 nmol/L [<30 ng/mL]) of serum 25-hydroxycholecalciferol (25-OHD) concentration is associated with increased risk of ARTI, and supplementation for those with deficiency/insufficiency may lead to clinically meaningful reductions in the incidence of ARTI. In this rapid review, vitamin D was primarily administered as oral supplementation, and findings suggested significant differences in daily oral dosing compared to periodic bolus dosing. Based on the available experimental evidence, vitamin D supplementation appears to have a high margin of safety with very few adverse events reported in children or adults from a variety of dosing strategies. Future clinical trials on vitamin D should consider the sources of heterogeneity in the existing experimental research and design trials that account for baseline status, evaluate the potential for prevention and treatment in at risk populations, standardize dosing strategies, assess product quality, assess outcomes according to gold standard definitions/diagnostic methods, and delineate viral ARTI from other causes when possible. The available mechanistic evidence related to immunological requirements for adequate vitamin D, the availability of observational and experimental evidence suggestive of clinically meaningful benefits (especially in deficient/insufficient participants), and the high margin of safety, should make vitamin D a high priority for additional clinical research during the current COVID-19 pandemic.

Malnutrition: Percentage and Association with Prognosis in Patients Hospitalized for Coronavirus Disease 2019

“…Indeed, a recent review has shown the importance of maintaining a correct nutritional status of 10 nutrients analyzed for the health of the immune system, highlighting especially the importance of Vitamin D and iron in the context of COVID-19 [39][40][41]. A wealth of mechanistic and clinical data has shown that vitamins, including vitamins A, B 6 , B 12 , C, D, E, and folate; trace elements, including zinc, iron, selenium, magnesium, and copper; and the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid play important and complementary roles in supporting the immune system.…”

A naturopathic treatment approach for mild and moderate COVID-19: A retrospective chart review

“… 2 , 98 , 99 , 100 Nutritional deficiencies can impair immune function and increase the risk for a more severe and chronic course of disease. 30 , 47 , 48 , 49 , 50 , 51 , 101 Malnutrition has been noted in 26-45% of patients with COVID-19. 5 A study on 50 hospitalized patients with SARS-CoV-2 revealed 76% were vitamin D deficient and 42% selenium deficient.…”

Strengthening the immunity of the Swiss population with micronutrients: A narrative review and call for action

“…Vitamin C deficiency results in impaired immunity, leading to increased rates and severity of infection such as pneumonia, whereas supplementation can reduce the incidence and severity of infection [5,42e44]. A recent review concluded that vitamin C supplementation may reduce symptoms of acute respiratory viral infections, as well as the incidence and duration of hospital stays [43]. Daily vitamin C supplementation at 200 mg or more, was reported to decrease severity and duration (8% in adults, 14e18% in children) of upper respiratory tract infections, including common cold [45].…”