COVID-19: Blood Biomarkers - Vitamin C

Written by ODX Research | Jul 27, 2021 10:00:00 PM

Vitamin C is more than just a vital amine in the COVID-19 fight

Dicken Weatherby, N.D. and Beth Ellen DiLuglio, MS, RDN, LDN

Vitamin C possesses antiviral, anti-inflammatory, antioxidant, and immunomodulating effects, making it a focus of research in COVID-19.

The ODX COVID-19 Series

Unlike most mammals, humans cannot produce vitamin C (ascorbic acid), making it an essential nutrient that must be obtained exogenously.[i] Hepatic production of vitamin C increases under stress (except for humans, primates, and guinea pigs).[ii]

An insufficiency of vitamin C contributes to increased susceptibility to viral infection and the adverse effects of prolonged inflammation.[iii]

A cross-sectional study of 14,519 adults participating in the NHANES III revealed that blood concentrations of vitamin C (and other antioxidants) were inversely correlated with CRP, likely a reflection of antioxidant depletion due to oxidative stress and inflammatory processes.[iv]

Vitamin C: [v]

Improves epithelial barrier integrity, natural killer cell activity, and neutrophil chemotaxis and phagocytosis
Stimulates proliferation of lymphocytes and production of interferon
Reduces release of proinflammatory cytokines
Scavenges oxygen-free radicals and counteracts oxidative stress from the cytokine storm
May help prevent ARDS which is characterized by oxidative damage to the lungs
Deficiency is common in septic patients, with an inverse correlation between serum vitamin C and multi-organ dysfunction in sepsis
Vitamin C levels in serum and in leukocytes decrease during the increased metabolic demands of infection.
Supplementation can help replete serum and leukocyte vitamin C if provided in high enough doses.
Meta-analysis of 1210 critically ill patients showed that providing 3-10 grams of IV vitamin C per day reduced mortality rate.
Supplementation should be adjusted as needed as high concentrations may be pro-oxidative.
Vitamin C may interfere with accuracy of glucometer readings due to it having a molecular structure similar to glucose.
Note that differences in the vitamin C transporter system within the body may influence the efficacy of vitamin C supplementation in certain individuals.[vi]
High dose supplementation may be contraindicated in those with G6PD dehydrogenase deficiency, renal failure, or those prone to oxalate kidney stones.
However, therapeutic doses of vitamin C below 16 gram/day may be tolerated in those with G6PD deficiency.[vii]

Low serum vitamin C has been recognized as a factor in pneumonia and sepsis for decades and supplementation has been shown to be therapeutic. These benefits appear to translate into benefits for COVID-19 patients as well. [viii]

Critically ill patients may need 20-30 times more vitamin C than the general population and several gram doses to normalize serum levels.
A randomized study of septic ARDS patients demonstrated that 200 mg/kg/day of vitamin C for four days was associated with a lower mortality rate of 30% versus 46% in the placebo group.
Meta-analysis revealed that vitamin C supplementation resulted in reduced mechanical ventilation and length of ICU stay
Serum vitamin C levels of 0.41 mg/dL (23 umol/L) are considered hypovitaminosis C and levels below 0.19 mg/dL (11 umol/L) were considered vitamin C deficient
The World Health Organization recognized adjunctive vitamin C as an intervention with biologic plausibility.
Several clinical trials are currently investigating the efficacy of vitamin C in the treatment of COVID-19

A small study of critically ill COVID-19 adults with ARDS revealed underlying vitamin C deficiency. The study found that 17 of 18 patients had undetectable serum vitamin C using a detection limit of 0.15 mg/dL (8.5 umol/L), while one patient had a deficient level of 0.24 mg/dL (13.5 umol/L).[ix]

Vitamin C insufficiency was detected in 21 critically ill COVID-19 ICU patients with a mean serum level of 0.39 mg/dL (22.2 umol/L), well below the standard hospital reference value of 0.51 mg/dL (29.1 umol/L). Mean vitamin D levels of 22 ng/mL (55 nmol/L) were also below normal hospital values of 30–100 ng/mL (75-250 nmol/L). Researchers strongly recommend assessing for and correcting insufficiencies of vitamins C and D.[x]

Standard reference range vitamin C

Quest Diagnostics[xi] Males 0.2-2.1 Females 0.3-2.7 mg/dL

Labcorp[xii] 0.4-2 mg/dL

Optimal ranges of vitamin C are higher than standard lab ranges. [xiii]

Vitamin C status	Serum vitamin C Optimal Range
Oral intake of vitamin C from foods	3-4 mg/dL (73.8-227 umol/L)
Maximal free radical scavenging	5 mg/dL (1000 umol/L)
IV vitamin C therapy	Greater than 350 mg/dL (20000-49000 umol/L)

Keep in mind that most mammals are taking care of their own vitamin C needs as you read this. Let’s make sure humans take care of their own needs too.

Next Up - COVID-19: Blood Biomarkers - Vitamin D

Research

[i] Drouin, Guy et al. “The genetics of vitamin C loss in vertebrates.” Current genomics vol. 12,5 (2011): 371-8. doi:10.2174/138920211796429736

[ii] Hoang, Ba X et al. “Possible application of high-dose vitamin C in the prevention and therapy of coronavirus infection.” Journal of global antimicrobial resistance vol. 23 (2020): 256-262. doi:10.1016/j.jgar.2020.09.025

[iii] Richardson, David P, and Julie A Lovegrove. “Nutritional status of micronutrients as a possible and modifiable risk factor for COVID-19: a UK perspective.” The British journal of nutrition, 1-7. 20 Aug. 2020, doi:10.1017/S000711452000330X

[iv] Ford, E S et al. “C-reactive protein concentration and concentrations of blood vitamins, carotenoids, and selenium among United States adults.” European journal of clinical nutrition vol. 57,9 (2003): 1157-63. doi:10.1038/sj.ejcn.1601667

[v] Abobaker, Anis et al. “Overview of the possible role of vitamin C in management of COVID-19.” Pharmacological reports : PR vol. 72,6 (2020): 1517-1528. doi:10.1007/s43440-020-00176-1

[vi] Patterson, Gregory, Carlos M. Isales, and Sadanand Fulzele. "Low level of Vitamin C and dysregulation of Vitamin C transporter might be involved in the severity of COVID-19 Infection." Aging and disease (2020): 0.

[vii] Hoang, Ba X et al. “Possible application of high-dose vitamin C in the prevention and therapy of coronavirus infection.” Journal of global antimicrobial resistance vol. 23 (2020): 256-262. doi:10.1016/j.jgar.2020.09.025

[viii] Carr, Anitra C, and Sam Rowe. “The Emerging Role of Vitamin C in the Prevention and Treatment of COVID-19.” Nutrients vol. 12,11 3286. 27 Oct. 2020, doi:10.3390/nu12113286

[ix] Chiscano-Camón, Luis et al. “Vitamin C levels in patients with SARS-CoV-2-associated acute respiratory distress syndrome.” Critical care (London, England) vol. 24,1 522. 26 Aug. 2020, doi:10.1186/s13054-020-03249-y

[x] Arvinte, Cristian et al. “Serum Levels of Vitamin C and Vitamin D in a Cohort of Critically Ill COVID-19 Patients of a North American Community Hospital Intensive Care Unit in May 2020: A Pilot Study.” Medicine in drug discovery vol. 8 (2020): 100064. doi:10.1016/j.medidd.2020.100064

[xi] Quest Diagnostics Vitamin C.

[xii] Labcorp Vitamin C.

[xiii] Klimant, E et al. “Intravenous vitamin C in the supportive care of cancer patients: a review and rational approach.” Current oncology (Toronto, Ont.) vol. 25,2 (2018): 139-148. doi:10.3747/co.25.3790

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