New Review Investigates Vitamin D Supplementation and Risk of Respiratory Tract Infections

Vitamin D deficiency is a global epidemic and has been linked to chronic diseases, with research finding a higher prevalence of these diseases in those who are deficient in vitamin D. 

Previous research has also shown that vitamin D supplementation helps reduce the risk of influenza. Viral infections often occur in the winter when vitamin D levels are the lowest and supplementation is often required in order to reach normal concentrations.

In a review published two weeks ago in Nutrients, researchers investigated vitamin D’s potential effect in helping to reduce the risk of respiratory tract infections.  

According to this review, a vitamin D deficiency has been associated with an increased risk of acute respiratory distress syndrome as well as chronic disease. An observational study in Connecticut which included 198 healthy adults in the fall and winter of 2009 through 2010 demonstrated a reduced risk of acute respiratory tract infections in those with a vitamin D insufficiency. Only 17% of individuals who had a vitamin D level greater than 38 ng/mL developed an acute upper respiratory tract infection compared to 45% in individuals with a vitamin D level less than 38 ng/mL. 

In addition, a high-dose vitamin D study using 250,000 IU or 500,000 IU in Georgia was conducted on ventilated intensive care unit patients. The average vitamin D level was 21 ng/ml and demonstrated a reduction in hospital length of stay from 36 days to 25 days in patients given 250,000 IU vitamin D while the hospital stay was reduced to 18 days in the 500,000 IU group. Vitamin D was also shown to significantly increase hemoglobin concentration, improving the body’s ability to transport oxygen efficiently. 

It is recommended for individuals at risk of influenza or acute respiratory tract infections to consider supplementing with 10,000 IU/d of vitamin D daily for several weeks to increase vitamin D levels and then decrease to 5000 IU per day. The research team suggests obtaining a vitamin D level of 40–60 ng/ml. In patients with an active infection slightly higher doses may be beneficial.  

The actions and metabolism of vitamin D are well known. Vitamin D helps reduce the risk of respiratory infections through cellular and adaptive immunity as well as providing a physical barrier. In addition, vitamin D helps maintain tight junctions and gap junctions. Previous research has demonstrated that viruses can disrupt junction integrity and increase the severity of the infection. Vitamin D also increases cellular immunity by reducing the cytokine storm triggered by the innate immune system. It helps support a healthy inflammatory response by reducing tumor necrosis factor-α and interferon-gamma as well as increasing T regulatory cells.

Vitamin D supplementation is a cost-effective intervention that can help lower the risk of respiratory tract and viral infections and can reduce health care costs. It is essential to use a supplement that combines vitamin K with D, or to provide vitamin K separately. There is no established ideal ratio between D and K1 or K2; however, each need to be optimized. It is also important to note that there is no toxicity of vitamin K. There are intricate relationships between fat-soluble vitamins and it is important take this into account when dosing vitamin D. Furthermore, magnesium helps to activate vitamin D, so magnesium supplementation should also be considered.

By Michael Jurgelewicz, DC, DACBN, DCBCN, CNS

Source: Grant WB, Lahore H, et al. Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths. Nutrients 2020 Apr 2;12(4).