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The Best Choice in Immune Support

MDCustomRx - Quality Matters
Now is the time for adequate immune support.

With back-to-school season in full swing and cold and flu season approaching, this time of year naturally brings about thoughts of immune support.  These thoughts are now heightened with news surrounding COVID, its variants and vaccine responses. 

How does a coronavirus function?

Coronaviruses are a large family of RNA viruses that cause a variety of diseases.  They are characterized by Spike proteins on their surfaces.  Seven coronaviruses have been identified to date.  Coronaviruses like COVID, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replicate by:
(1) The virus binds to its host receptor cell – in the case of SARS-CoV-2, this occurs when the Spike protein bonds at the angiotensin converting enzyme 2 (ACE2) receptor protein site.
(2) The virus then enters the cell and fuses with the cellular membrane.
(3) The virus releases its genetic material into the cell.
(4) The viral RNA is transcribed and the viral mRNA directs protein synthesis (this process is unique to coronaviruses).
(5) The virus can now replicate and assembles new virions that are released from the cell surface to further infect neighboring cells.

Potential interventions against SARS-CoV-2 can generally be divided into two categories (1) interventions that act on the human immune system and (2) interventions that act on the virus itself.

Possible Interventions:


From the barrier of the skin to gene regulation within lymphocytes, zinc contributes to immune support through various cellular functions of both the innate and adaptive immune system.  There is also evidence that zinc suppresses viral attachment and replication.  Specific to SARS-coronavirus, zinc suppresses replication by interfering with proteolytic processing of polyproteins in RNA viruses.   And what’s worse is that zinc deficiency is common and a zinc deficiency impairs overall immune function and resistance to infection!  A study in nursing home elderly showed that compared with subjects with low zinc concentrations, subjects with normal zinc concentrations had a lower incidence of pneumonia, fewer new antibiotic prescriptions, a shorter duration of pneumonia and fewer days of antibiotic use.  The data clearly demonstrates that immune integrity is tightly linked to zinc status.  Supplementation with zinc is supported by evidence that it both prevents viral infections and reduces their severity and duration.  Moreover, it has been shown to reduce the risk of lower respiratory infection.  If you are curious as to whether you or your loved ones may be Zinc deficient, you can test your level with a test kit obtained through MD Custom Rx. 

You can test your Zinc level with a test kit obtained through MD Custom Rx.

VITAMIN D[1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],[23],[24],[25],[26]

Activated vitamin D, a steroid hormone, is an immune system modulator that reduces the expression of inflammatory cytokines and increases macrophage function.  Vitamin D also stimulates the expression of potent antimicrobial peptides (AMPs), which exist in neutrophils, monocytes, natural killer cells and epithelial cells of the respiratory tract.  Vitamin D increases anti-pathogen peptides through defensins and has a dual effect due to suppressing superinfection.  Evidence suggests vitamin D supplementation may prevent upper respiratory infections.  The benefits that Vitamin D carries out through the body are vast due to the gene expression and signal transduction that it carries out in virtually every tissue.  To this end, Vitamin D has been demonstrated to exhibit multiple properties including anti-inflammatory, anti-bacterial, anti-proliferative and cytoprotection against endogenous and exogenous stresses.  You can test your vitamin D level with a test kit obtained through MD Custom Rx.  It can take months of supplementation to get your Vitamin D level to increase.  Therefore, a loading dose is often used to get you to where you need to be quicker.  MD Custom Rx has access to a dosing calculator.  All we need to know is (1) How much Vitamin D3 you were supplementing with at the time of testing (2) Your current weight and (3) Your current Vitamin D level.  Let us help you optimize your Vitamin D level today!

You can test your vitamin D level with a test kit obtained through MD Custom Rx. 

N-ACETYLCYSTEINE (NAC)[1],[2],[3],[4],[5],[6],[7]

N-acetylcysteine promotes glutathione production, which helps maintain immune support.  Through its ability to raise glutathione levels, NAC is able to protect the biologic activity and safe metabolism of quercetin.  NAC has been shown to support mucus clearance and normal respiratory function, through its ability to cleave disulfide bonds in mucus.  In a little-noticed six-month controlled clinical study enrolling 262 primarily elderly subjects, those receiving 600mg NAC twice daily, as opposed to those receiving placebo, experienced significantly fewer influenza-like episodes and days of bed confinement.


Quercetin may be best known for its antioxidant activity in scavenging free radicals, but it has also been shown to have antiviral effects against both RNA (e.g., influenza and coronavirus) and DNA viruses (e.g., herpesvirus).  Quercetin has a pleiotropic role as an antioxidant and anti-inflammatory, modulating signaling pathways that are associated with post-transcriptional modulators affecting post-viral healing.  Additionally, quercetin helps balance the level of cytokines and improve T-lymphocyte balance while also stimulating the ciliary beat frequency of the nasal epithelium, aiding the excretion of respiratory mucus.  Quercetin has been shown to block the mechanisms by which microbes enter the host cells and replicate within the body, thereby providing immune support.  

VITAMIN C[1],[2],[3],[4]

Vitamin C is a potent antioxidant that has been studied for many years for its immune support effects.  Vitamin C contributes to immune support through various cellular functions of both the innate and adaptive immune system.  Vitamin C accumulates in phagocytic cells, such as neutrophils, and can enhance chemotaxis, phagocytosis, generation of reactive oxygen species, and ultimately microbial killing.  Supplementation with vitamin C appears to be able to prevent and treat respiratory and systemic infections.  Vitamin C has been used in hospital ICUs to treat COVID-19 infection.  Data shows vitamin C is heavily concentrated in macrophages, supports lymphocyte activity, modulates cytokine release, improves endothelial function, restores mitochondrial function, and can directly provide immune support to a challenged immune system.  Of particular interest, vitamin C has been shown to recycle oxidized quercetin back to its parent compound, which supports a robust immune response while increasing the efficacy of quercetin.


Now if you’ve made it to reading this far, you are likely thinking – “Great!  Now I need to add 5 more supplements to my regimen for immune support!”  What if I told you that is not the case?  What if, there was this great new product available at MD Custom Rx, which combines all 5 of these great nutrients into a single capsule and all you have to do is take 2 capsules daily.  Well, it’s true!  OrthoMune is a targeted blend of the 5 aforementioned nutrients designed to provide broad-spectrum immune support to the body.  Get yours today!

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[2] Zabet MH, Mohammadi M, Ramezani M, Khalili H. Effect of high-dose ascorbic acid on vasopressor’s requirement in septic shock. J Res Pharm Pract. 2016;5(2):94-100. doi:10.4103/2279-042X.179569

[3] Fowler AA, Truwit JD, Hite RD, et al. Effect of vitamin C infusion on organ failure and biomarkers of inflammation and vascular injury in patients with sepsis and severe acute respiratory failure. JAMA. 2019;322(13):1261-1270. doi:10.1001/jama.2019.11825

[4] Boots AW, Haenen GR, Bast A. Health effects of quercetin: from antioxidant to nutraceutical. European journal of pharmacology. 2008;585(2-3):325-337.

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[2] Therapeutic Research Center. Natural Medicines Database: Quercetin. https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=434#adverseEvents. Accessed September 21, 2020.

[3] Wu W, Li R, Li X, et al. Quercetin as an antiviral agent inhibits influenza A virus (IAV) entry. Viruses. 2015;8(1):6. doi:10.3390/v8010006

[4] Kinker B, Comstock AT, Sajjan US. Quercetin: a promising treatment for the common cold. J Anc Dis Prev Rem. 2014;2:2:1000111. doi:10.4172/2329-8731.1000111

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[6]  Qiu X, Kroeker A, He S, et al. Prophylactic efficacy of quercetin 3-?-O-D-glucoside against Ebola virus infection. Antimicrob Agents Chemother. 2016;60(9):5182-5188. doi:10.1128/AAC.00307-16

[7]Wong G, He S, Siragam V, et al. Antiviral activity of quercetin-3-?-O-D-glucoside against Zika virus infection. Virol Sin. 2017;32(6):545-547. doi:10.1007/s12250-017-4057-9

[8] T?zsér J, Benk? S. Natural compounds as regulators of NLRP3 inflammasome-mediated IL-1? production. Mediators Inflamm. 2016;2016:5460302. doi:10.1155/2016/5460302

[9] Yi YS. Regulatory roles of flavonoids on inflammasome activation during inflammatory responses. Mol Nutr Food Res. 2018;62(13):e1800147. doi:10.1002/mnfr.201800147

[10] Nieman DC, Henson DA, Gross SJ, et al. Quercetin reduces illness but not immune perturbations after intensive exercise. Med Sci Sports Exerc. 2007;39(9):1561-1569. doi:10.1249/mss.0b013e318076b566

[11] Colunga Biancatelli RML, Berrill M, Catravas JD, Marik PE. Quercetin and Vitamin C: An Experimental, Synergistic Therapy for the Prevention and Treatment of SARS-CoV-2 Related Disease (COVID-19). Frontiers in immunology. 2020;11:1451.

[12] Mehrbod P, Hudy D, Shyntum D, Markowski J, Łos MJ, Ghavami S. Quercetin as a Natural Therapeutic Candidate for the Treatment of Influenza Virus. Biomolecules. 2020;11(1).

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[2] De Flora S, Grassi C, Carati L. Attenuation of influenza-like symptomatology and improvement of cell-mediated immunity with long-term N-acetylcysteine treatment. Eur Respir J. 1997;10(7):1535-1541. doi:10.1183/09031936.97.10071535

[3] De Rosa SC, Zaretsky MD, Dubs JG, et al. N-acetylcysteine replenishes glutathione in HIV infection. European journal of clinical investigation. 2000;30(10):915-929.

[4] Aldini G, Altomare A, Baron G, et al. N-Acetylcysteine as an antioxidant and disulphide breaking agent: the reasons why. Free Radic Res. 2018;52(7):751-762.

[5] Rushworth GF, Megson IL. Existing and potential therapeutic uses for N-acetylcysteine: the need for conversion to intracellular glutathione for antioxidant benefits. Pharmacology & therapeutics. 2014;141(2):150-159.

[6] Grandjean EM, Berthet P, Ruffmann R, Leuenberger P. Efficacy of oral long-term N-acetylcysteine in chronic bronchopulmonary disease: a meta-analysis of published double-blind, placebo-controlled clinical trials. Clinical therapeutics. 2000;22(2):209-221.

[7] Falluel-Morel A, Lin L, Sokolowski K, McCandlish E, Buckley B, DiCicco-Bloom E. N-acetyl cysteine treatment reduces mercury-induced neurotoxicity in the developing rat hippocampus. J Neurosci Res. 2012;90(4):743-750.

[1] Mawson AR. Role of fat-soluble vitamins A and D in the pathogenesis of influenza: a new perspective. Int Sch Res Notices. 2013;2013:246737. doi:10.5402/2013/246737

[2] Martineau AR, Jolliffe DA, Greenberg L, et al. Vitamin D supplementation to prevent acute respiratory infections: individual participant data meta-analysis. Health Technol Assess. 2019;23(2):1-44. doi:10.3310/hta23020

[3] Zhou J, Du J, Huang L, Wang Y, Shi Y, Lin H. Preventive effects of vitamin D on seasonal influenza A in infants: multicenter, randomized, open, controlled clinical trial. Pediatr Infect Dis J. 2018;37(8):749-754. doi:10.1097/INF.0000000000001890

[4] Tzilas V, Bouros E, Barbayianni I, et al. Vitamin D prevents experimental lung fibrosis and predicts survival in patients with idiopathic pulmonary fibrosis. Pulm Pharmacol Ther. 2019;55:17-24. doi:10.1016/j.pupt.2019.01.003

[5] Ricca C, Aillon A, Viano M, Bergandi L, Aldieri E, Silvagno F. Vitamin D inhibits the epithelial-mesenchymal transition by a negative feedback regulation of TGF-? activity. J Steroid Biochem Mol Biol. 2019;187:97-105. doi:10.1016/j.jsbmb.2018.11.006

[6] Fischer KD, Agrawal DK. Vitamin D regulating TGF-? induced epithelial-mesenchymal transition [published correction appears in Respir Res. 2015;16:139]. Respir Res. 2014;15:146. doi:10.1186/s12931-014-0146-6

[7] Schrumpf JA, Ninaber DK, van der Does AM, Hiemstra PS. TGF-?1 impairs vitamin D-induced and constitutive airway epithelial host defense mechanisms. J Innate Immun. 2020;12(1):74-89. doi:10.1159/000497415

[8] Liu RM, Gaston Pravia KA. Oxidative stress and glutathione in TGF-beta-mediated fibrogenesis. Free Radic Biol Med. 2010;48(1):1-15. doi:10.1016/j.freeradbiomed.2009.09.026

[9] Lu L, Lu Q, Chen W, Li J, Li C, Zheng Z. Vitamin D3 protects against diabetic retinopathy by inhibiting high-glucose-induced activation of the ROS/TXNIP/NLRP3 inflammasome pathway. J Diabetes Res. 2018;2018:8193523. doi:10.1155/2018/8193523

[10] Rao Z, Chen X, Wu J, et al. Vitamin D receptor inhibits NLRP3 activation by impeding its BRCC3-mediated deubiquitination. Front Immunol. 2019;10:2783. doi:10.3389/fimmu.2019.02783

[11] Hewison M. Vitamin D and immune function: an overview. Proc Nutr Soc. 2012;71(1):50-61. doi:10.1017/S0029665111001650

[12] Fitch N, Becker AB, HayGlass KT. Vitamin D [1,25(OH)2D3] differentially regulates human innate cytokine responses to bacterial versus viral pattern recognition receptor stimuli. J Immunol. 2016;196(7):2965-2972. doi:10.4049/jimmunol.1500460

[13] Zdrenghea MT, Makrinioti H, Bagacean C, Bush A, Johnston SL, Stanciu LA. Vitamin D modulation of innate immune responses to respiratory viral infections. Rev Med Virol. 2017;27(1). doi:10.1002/rmv.1909

[14] Verway M, Bouttier M, Wang TT, et al. Vitamin D induces interleukin-1? expression: paracrine macrophage epithelial signaling controls M. tuberculosis infection. PLoS Pathog. 2013;9(6):e1003407. doi:10.1371/journal.ppat.1003407

[15] Tulk SE, Liao KC, Muruve DA, Li Y, Beck PL, MacDonald JA. Vitamin D3 metabolites enhance the NLRP3-dependent secretion of IL-1? from human THP-1 monocytic cells. J Cell Biochem. 2015;116(5):711-720. doi:10.1002/jcb.24985

[16] Lee MT, Kattan M, Fennoy I, et al. Randomized phase 2 trial of monthly vitamin D to prevent respiratory complications in children with sickle cell disease. Blood Adv. 2018;2(9):969-978. doi:10.1182/bloodadvances.2017013979

[17] Autier P, Mullie P, Macacu A, et al. Effect of vitamin D supplementation on non-skeletal disorders: a systematic review of meta-analyses and randomised trials. Lancet Diabetes Endocrinol. 2017;5(12):986-1004. doi:10.1016/S2213-8587(17)30357-1

[18] Sluyter JD, Camargo CA, Waayer D, et al. Effect of monthly, high-dose, long-term vitamin D on lung function: a randomized controlled trial. Nutrients. 2017;9(12):E1353. doi:10.3390/nu9121353

[19] Turin A, Bax JJ, Doukas D, et al. Interactions among vitamin D, atrial fibrillation, and the renin-angiotensin-aldosterone system. Am J Cardiol. 2018;122(5):780-784. doi:10.1016/j.amjcard.2018.05.013

[20]  Zaheer S, Taquechel K, Brown JM, Adler GK, Williams JS, Vaidya A. A randomized intervention study to evaluate the effect of calcitriol therapy on the renin-angiotensin system in diabetes. J Renin Angiotensin Aldosterone Syst. 2018;19(1):1470320317754178. doi:10.1177/1470320317754178

[21] Cremer A, Tambosco C, Corcuff JB, et al. Investigating the association of vitamin D with blood pressure and the renin-angiotensin-aldosterone system in hypertensive subjects: a cross-sectional prospective study. J Hum Hypertens. 2018;32(2):114-121. doi:10.1038/s41371-017-0005-2

[22] Zittermann A, Ernst JB, Prokop S, et al. Effects of vitamin D supplementation on renin and aldosterone concentrations in patients with advanced heart failure: the EVITA trial. Int J Endocrinol. 2018;2018:5015417. doi:10.1155/2018/5015417

[23] Yang P, Gu H, Zhao Z, et al. Angiotensin-converting enzyme 2 (ACE2) mediates influenza H7N9 virus-induced acute lung injury. Sci Rep. 2014;4:7027. doi:10.1038/srep07027

[24] Xu J, Yang J, Chen J, Luo Q, Zhang Q, Zhang H. Vitamin D alleviates lipopolysaccharide-induced acute lung injury via regulation of the renin-angiotensin system. Mol Med Rep. 2017;16(5):7432-7438. doi:10.3892/mmr.2017.7546

[25] Scragg R. The vitamin D assessment (ViDA) study – design and main findings. J Steroid Biochem Mol Biol. 2020;198:105562. doi:10.1016/j.jsbmb.2019.105562

[26] Camargo CA Jr, Ganmaa D, Frazier AL, et al. Randomized trial of vitamin D supplementation and risk of acute respiratory infection in Mongolia. Pediatrics. 2012;130(3):e561-e567. doi:10.1542/peds.2011-3029

[1] Fischer WC, Black RE. Zinc and the risk for infectious disease. Annu Rev Nutr. 2004;24:255-275. doi:10.1146/annurev.nutr.23.011702.073054

[2] Fraker PJ, King LE, Laakko T, Vollmer TL. The dynamic link between the integrity of the immune system and zinc status. J Nutr. 2000;130(5S Suppl):1399S-1406S. doi:10.1093/jn/130.5.1399S

[3] Shankar AH, Prasad AS. Zinc and immune function: the biological basis of altered resistance to infection. Am J Clin Nutr. 1998;68(2 Suppl):447S-463S. doi:10.1093/ajcn/68.2.447S

[4] Gao H, Dai W, Zhao L, Min J, Wang F. The role of zinc and zinc homeostasis in macrophage function. J Immunol Res. 2018;2018:6872621 doi:10.1155/2018/6872621

[5] Meydani SN, Barnett JB, Dallal GE, et al. Serum zinc and pneumonia in nursing home elderly. Am J Clin Nutr. 2007;86(4):1167-1173. doi:10.1093/ajcn/86.4.1167

[6] Barnett JB, Dao MC, Hamer DH, et al. Effect of zinc supplementation on serum zinc concentration and T cell proliferation in nursing home elderly: a randomized, double-blind, placebo-controlled trial. Am J Clin Nutr. 2016;103(3):942-951. doi:10.3945/ajcn.115.115188

[7] Maares M, Haase H. Zinc and immunity: an essential interrelation. Arch Biochem Biophys. 2016;611:58-65. doi:10.1016/j.abb.2016.03.022

[8] te Velthuis AJW, van den Worm SHE, Sims AC, Baric RS, Snijder EJ, van Hemert MJ. Zn(2+) inhibits coronavirus and arterivirus RNA polymerase activity in vitro and zinc ionophores block the replication of these viruses in cell culture. PLoS Pathog. 2010;6(11):e1001176. doi:10.1371/journal.ppat.1001176

[9] Acevedo-Murillo JA, García León ML, Firo-Reyes V, Santiago-Cordova JL, Gonzalez-Rodriguez AP, Wong-Chew RM. Zinc supplementation promotes a Th1 response and improves clinical symptoms in fewer hours in children with pneumonia younger than 5 years old. A randomized controlled clinical trial. Front Pediatr. 2019;7:431. doi:10.3389/fped.2019.00431

[10] Finzi E. Treatment of SARS-CoV-2 with high dose oral zinc salts: a report on four patients. Int J Infect Dis. 2020;99:307-309. doi:10.1016/j.ijid.2020.06.00

[11] Rerksuppaphol S, Rerksuppaphol L. A randomized controlled trial of zinc supplementation in the treatment of acute respiratory tract infection in Thai children. Pediatr Rep. 2019;11(2):7954. doi:10.4081/pr.2019.7954

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