--- title: "COVID-19: Blood Biomarkers - Vitamin C" description: COVID-19 Blood Biomarkers -Vitamin C | OptimalDX.com Functional Blood Chemistry Analysis --- [The Optimal DX Research Blog ](https://www.optimaldx.com/research-blog) # [COVID-19: Blood Biomarkers - Vitamin C](https://www.optimaldx.com/research-blog/covid-19-blood-biomarkers-vitamin-c) Written by [ODX Research](https://www.optimaldx.com/research-blog/author/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 1. [COVID-19: The pandemic that has become endemic](https://www.optimaldx.com/research-blog/covid-19-comorbidities-risk-factors-blood-biomarkers) 2. [COVID-19: Overlapping risk factors and chronic disease](https://www.optimaldx.com/research-blog/covid-19-overlapping-risk-factors-and-chronic-disease) 3. [Nutritional status COVID-19: A covert factor in disease susceptibility](https://www.optimaldx.com/research-blog/nutritional-status-and-covid-19) 4. [COVID-19: Blood chemistry biomarker patterns - Clues and patterns lurking just under the surface](https://www.optimaldx.com/research-blog/covid-19-blood-chemistry-biomarkers-clues-patterns) 5. [COVID-19: Blood chemistry biomarker patterns - Down the research rabbit hole](https://www.optimaldx.com/research-blog/covid-19-blood-chemistry-biomarkers-down-research-rabbit-hole) 6. [COVID-19: Blood Biomarkers - Neutrophils](https://www.optimaldx.com/research-blog/covid-19-blood-biomarkers-neutrophil) 7. [COVID-19: Blood Biomarkers - Albumin](https://www.optimaldx.com/research-blog/covid-19-blood-biomarkers-albumin) 8. [COVID-19: BloodBiomarkers - Cytokines](https://www.optimaldx.com/research-blog/covid-19-blood-biomarkers-cytokines) 9. [COVID-19: Blood Biomarkers - Interleukin-6](https://www.optimaldx.com/research-blog/covid-19-blood-biomarkers-interleukin-6) 10. [COVID-19: Blood Biomarkers - Interleukin-10](https://www.optimaldx.com/research-blog/covid-19-blood-biomarkers-interleukin-10) 11. [COVID-19: Blood Biomarkers - Vitamin C](https://www.optimaldx.com/research-blog/covid-19-blood-biomarkers-vitamin-c) 12. [COVID-19: Blood Biomarkers - Vitamin D](https://www.optimaldx.com/research-blog/covid-19-blood-biomarkers-vitamin-d) 13. [COVID-19: Blood Biomarkers - Zinc](https://www.optimaldx.com/research-blog/covid-19-blood-biomarkers-zinc) 14. [Biomarker characteristics and blood type - help sharpen the COVID-19 clinical picture](https://www.optimaldx.com/research-blog/covid-19-blood-type) 15. [COVID-19: Initial indications and conventional interventions](https://www.optimaldx.com/research-blog/covid-19-initial-indications-conventional-interventions) 16. [COVID-19: Long-term risk reduction - Naturopathic, functional medicine, and nutrition-based approaches to prevention](https://www.optimaldx.com/research-blog/covid-19-long-term-risk-reduction) 17. [A healthy diet is primary prevention for COVID-19](https://www.optimaldx.com/research-blog/covid-19-health-diet-for-primary-prevention) 18. [You should have a gut feeling about COVID-19](https://www.optimaldx.com/research-blog/gi-microbiome-and-covid-susceptibility) 19. [Beyond dietary food patterns…plant-based compounds may mitigate COVID-19 risk](https://www.optimaldx.com/research-blog/covid-19-plant-based-foods-may-mitigate-covid-19-risk) 20. [Targeted nutrition support in the battle against COVID-19](https://www.optimaldx.com/research-blog/covid-19-targeted-nutrition-support) 21. [Targeted nutrition support in COVID-19: Armed with vitamin C](https://www.optimaldx.com/research-blog/covid-19-targeted-nutrition-support-vitamin-c) 22. [Targeted nutrition support in COVID-19: In sync with zinc](https://www.optimaldx.com/research-blog/covid-19-targeted-nutrition-support-zinc) 23. [Targeted nutrition support in COVID-19: Micronutrients and phytonutrients are important players](https://www.optimaldx.com/research-blog/covid-19-targeted-nutrition-support-micronutrients-phytonutrients) 24. [Optimal Takeaways for improving immunity and reducing susceptibility to COVID-19](https://www.optimaldx.com/research-blog/covid-19-optimal-takeaways-for-improving-immunity-reducing-susceptibility) 25. [Optimal - The Podcast: Episode 8 -Blood Biomarkers and Risk Factors for COVID-19 and its Comorbidities](https://www.optimaldx.com/blog/optimal-the-podcast-episode-8-covid-biomarkers-risk-factors) 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](https://www.optimaldx.com/research-blog/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  [View full post](https://www.optimaldx.com/research-blog/covid-19-blood-biomarkers-vitamin-c) ```json { "@context" : "http://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "ODX Research" }, "dateModified" : "2021-08-13T20:52:57.088Z", "datePublished" : "2021-07-27T22:00:00Z", "headline" : "COVID-19: Blood Biomarkers - Vitamin C", "image" : { "@type" : "ImageObject", "height" : 500, "url" : "https://f.hubspotusercontent20.net/hubfs/5340373/COVID-19_Update_1000x500.png", "width" : 1000 }, "mainEntityOfPage" : "https://www.optimaldx.com/research-blog/covid-19-blood-biomarkers-vitamin-c", "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "height" : 60, "url" : "/hs/hsstatic/content_shared_assets/static-1.4092/img/default-amp-logo.png", "width" : 60 }, "name" : "The Optimal DX Research Blog" } } ```