Page 21 - IMCJ19s1

Supporting levels of vitamins, minerals, and other the resolution phase. Isolating the role of vitamin D in
substances with known immunological roles. allowing macrophages to respond normally to
The role of nutritional agents as immune modulators pathogens does not reflect the total picture of vitamin
has recently been reviewed. It’s noteworthy that many of D’s role in the body. Vitamin D plays a key role in
185
these nutrients play dual roles in immunology, supporting both immune system antipathogenic function and
immune surveillance while also reducing inflammation. anti-inflammatory functions.

Vitamin D - The potential utility of vitamin D in ii. Vitamin A - Vitamin A was the first fat-soluble
COVID-19 has been reviewed, with the authors vitamin to be identified. Early researchers found that
recommending a multi-day loading of 10 000 iu qd young animals fed a diet deficient in natural fats
and a steady dose of 5000 iu qd, with the goal of became very unhealthy and that their eyes became
bringing lab ranges above 40-60 ng/ml. severely inflamed and infected. Vitamin A was once
186
Many studies have shown that vitamin D deficiency known as the “anti-infective vitamin,” and vitamin A
not only impairs immune function but also promotes status is a major determinant of overall immune status.
excessive inflammatory reactions. The role of vitamin D Those deficient in vitamin A experience impaired
in inflammatory and autoimmune disorders has been antibody response, decreased levels of helper T cells,
extensively reviewed, including here. Deficiency has and impaired integrity of the mucosal linings of the
187
been shown in many inflammatory and autoimmune respiratory and gastrointestinal tracts. Vitamin A–
diseases such as asthma, various types of arthritis, deficient individuals are more susceptible to infectious
189
188
SLE, Type 1 diabetes, Multiple Sclerosis, among diseases, respiratory conditions like asthma and
190
191
192
others. Supplementation is most likely primarily allergies, and have higher mortality rates.
197
effective in those deficient in vitamin D or with a VDR The prevalence of deficiency is difficult to
polymorphism impairing vitamin D absorption and determine as numbers vary widely worldwide and
metabolism. criteria are inconsistent. Nonetheless, deficiency is
193
A meta-analysis of studies on vitamin D and acute common worldwide, with epidemic prevalence in
lung injury (ALI) found that, in studies that did not use Saharan Arica (48%) and South Asia (44%).
198
very large, rare bolus dosing, vitamin D was safe and Unfortunately, vitamin A deficiency is also
protected against ALI. Patients who were deficient and common in the US with 34% of adults consuming less
received non-bolus dosing had the most benefit. than the EAR. Co-author Pizzorno in an unpublished
194
199
Vitamin D has been shown to prevent experimental study of retinol levels in 200 adult oil field workers in
lung fibrosis and predict survival in patients with Canada found that 40% were deficient.
idiopathic pulmonary fibrosis, via inhibition of While beta-carotene is commonly considered
TGFβ. TGFβ is a central player in lung fibrosis and a synonymous with vitamin A, this an error with
138
central generator of the NETosis discussed above, that significant clinical consequences, especially for vegans.
is associated with sepsis, thickening mucous secretions, Emerging research has shown multiple, surprisingly
and thrombus formation. Vitamin D has also been common, genomic variations that impair conversion of
shown to reduce the risk of acute respiratory beta-carotene to vitamin A by 24 to 57%. Single
infection. nucleotide polymorphisms have been identified that
195
Vitamin D is necessary for the formation of decrease activity of 15,15’-monoxygenase, the key
macrophage lysosomal enzymes, a key component of enzyme converting beta-carotene to retinol.
the ability of macrophages to kill pathogens, including rs12934922) and rs7501331 variants have been found
viruses, that have been engulfed by phagocytosis. In in 42% and 24%, respectively. Those with one copy of
196
many experimental models, macrophages are infected the less common allele have shown a 32% drop in
with pathogen in vitro, and the cytokine profiles the activity, while those who are homozygous for the
macrophages generate are measured. As described in polymorphism experience a 57% reduction in
the work of Hewison, healthy macrophages with conversion rate.
196
200
adequate vitamin D status will respond more A controlled animal study in calves found that
effectively to infection. This includes greater low dietary vitamin A impaired IgG1 titers against
production of cytokines whose function is to stimulate intramuscularly inoculated inactivated bovine
chemotaxis of neutrophils and other immune coronavirus vaccine.
201
elements to the site of infection. Effective neutrophil Vitamin A levels drop during various types of
chemotaxis is induced by inflammatory cytokines, infection and multiple studies have shown that
and neutrophil influx into tissue is at the center of vitamin A supplementation improves resistance and
normal anti-pathogenic inflammation. These recovery rate. Given the numbers above regarding
202
chemical signals are normal in the context of a the high prevalence of vitamin A deficiency, this is
well-orchestrated inflammatory response, including cause for concern in the current crisis.

Yanuck—Immuno-physiological Approach to COVID-19 Integrative Medicine • Vol. 19, No. S1 • Epub Ahead of Print 19