Vitamin C and pneumonia & other severe infections

by Harri Hemilä

Department of Public Health
University of Helsinki, Finland
harri.hemila@helsinki.fi
https://www.mv.helsinki.fi/home/hemila
Feb 12, 2025

Sepsis
Pneumonia
Tuberculosis
Tetanus
Other infections

Sepsis

Hemilä H, Chalker E.
Vitamin C for patients with sepsis?
Front Med (Lausanne). 2024
https://pubmed.ncbi.nlm.nih.gov/39364019

Hemilä H, Chalker E.
Rebound effect explains the divergence in survival after 5 days in a controlled trial on vitamin C for COVID-19 patients.
Front Med (Lausanne). 2024
https://pubmed.ncbi.nlm.nih.gov/38841576

Hemilä H, Chalker E.
Abrupt termination of vitamin C from ICU patients may increase mortality: secondary analysis of the LOVIT trial.
Eur J Clin Nutr. 2023
https://pubmed.ncbi.nlm.nih.gov/36539454

Hemilä H, Chalker E.
Reanalysis of the Effect of Vitamin C on Mortality in the CITRIS-ALI Trial: Important Findings Dismissed in the Trial Report.
Front Med (Lausanne). 2020
https://pubmed.ncbi.nlm.nih.gov/33117837

Hemilä H.
The protective effect of vitamins a and C on endotoxin-induced oxidative renal tissue damage in rats.
Tohoku J Exp Med. 2006
https://pubmed.ncbi.nlm.nih.gov/16434830

Pneumonia

Hemilä H, Chalker E.
Vitamin C for the common cold and pneumonia.
Pol Arch Intern Med. 2025
https://pubmed.ncbi.nlm.nih.gov/39803741

Flaws in Mendelian randomization study on vitamin C and pneumonia
Hemilä H, Chalker E.
Assessment of vitamin C effects on pneumonia and COVID-19 using Mendelian randomization: analysis may be misleading.
Eur J Clin Nutr. 2022
https://doi.org/10.1038/s41430-022-01091-9
https://www.ncbi.nlm.nih.gov/pmc/articles/pmc8853427

Flaws in Cochrane review (2020) on vitamin C and pneumonia
Hemilä H, Chalker E.
Commentary: Vitamin C supplementation for prevention and treatment of pneumonia.
Front Med (Lausanne). 2021
https://doi.org/10.3389/fmed.2020.595988
https://www.ncbi.nlm.nih.gov/pmc/articles/pmc7854566

Flawed review on vitamin C and respiratory infections
Hemilä H, Chalker E.
Commentary: the long history of vitamin C: from prevention of the common cold to potential aid in the treatment of COVID-19.
Front Immunol. 2021
https://doi.org/10.3389/fimmu.2021.659001
https://www.ncbi.nlm.nih.gov/pmc/articles/pmc8047412

Flawed approach to use "network pharmacology" to analyze vitamin C effect on pneumonia
Hemilä H, Carr A.
Comment on "Therapeutic target and molecular mechanism of vitamin C-treated pneumonia: a systematic study of network pharmacology" by R. Li, C. Guo, Y. Li, X. Liang, L. Yang and W. Huang,
Food Funct., 2020
https://doi.org/10.1039/d0fo02189j

Three controlled trials have found significant decrease in the incidence of pneumonia and two found treatment benefit for pneumonia patients.
Hemilä H, Louhiala P.
Vitamin C for preventing and treating pneumonia.
Cochrane Database Syst Rev 2013; CD005532
https://hdl.handle.net/10138/225862
https://www.mv.helsinki.fi/home/hemila/CP/2013_Coch_Pneu_CD005532.pdf
https://doi.org/10.1002/14651858.cd005532.pub3
https://pubmed.ncbi.nlm.nih.gov/23925826/

References to the review:
https://www.mv.helsinki.fi/home/hemila/CP

Hemilä H. Vitamin C and Community-acquired Pneumonia.
AJRCCM 2011;184:621-2.
https://doi.org/10.1164/ajrccm.184.5.621a

Modification of vitamin E effect by vitamin C also means that vitamin C influences pneumonia risk.
Hemilä H, Kaprio J.
Vitamin E supplementation and pneumonia risk in males who initiated smoking at an early age: effect modification by body weight and vitamin C. Nutr J 2008;7:33
https://doi.org/10.1186%2F1475-2891-7-33
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2603040/

Hemilä H.
Exercise, antioxidants, and the risk for pneumonia.
Med Sci Sports Exerc. 2015
https://doi.org/10.1249/mss.0000000000000544
https://www.mv.helsinki.fi/home/hemila/H/2015_L_MSSE.pdf

A short review
Hemilä H, Louhiala P.
Vitamin C may affect lung infections.
JRSM 2007;100:495-498
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2099400/
https://doi.org/10.1177/014107680710001109

Hemilä H.
Vitamin C supplementation and respiratory infections: a systematic review.
Military Medicine 2004;169:920-925
https://hdl.handle.net/10138/225867
https://www.researchgate.net/publication/8123995
https://doi.org/10.7205/milmed.169.11.920
https://www.mv.helsinki.fi/home/hemila/H/HH_2004.pdf
https://www.ncbi.nlm.nih.gov/pubmed/15605943

Hemilä H, Douglas RM.
Vitamin C and acute respiratory infections.
Int J Tuberc Lung Dis. 1999
https://www.ingentaconnect.com/content/iuatld/ijtld/1999/00000003/00000009/art00004
https://www.mv.helsinki.fi/home/hemila/H/HH_1999_IJTLD.pdf
https://www.ncbi.nlm.nih.gov/pubmed/10488881

Hemilä H.
Vitamin C intake and susceptibility to pneumonia.
Pediatr Infect Dis J 1997;16:836-837
https://www.researchgate.net/publication/13914252
https://hdl.handle.net/10138/225875
https://doi.org/10.1097/00006454-199709000-00003
https://zenodo.org/doi/10.5281/zenodo.10960785
https://www.mv.helsinki.fi/home/hemila/H/HH_1997_PIDJ.pdf

Tuberculosis

Modification of vitamin E effect by vitamin C also means that vitamin C influences TB risk.
Furthermore, high dietary vitamin C intake was associated with 60% lower TB risk in the participants who were not administered vitamin E.

Hemilä H, Kaprio J.
Vitamin E supplementation may transiently increase tuberculosis risk in males who smoke heavily and have high dietary vitamin C intake. Br J Nutr 2008;100:896-902
https://doi.org/10.1017/s0007114508923709
https://pubmed.ncbi.nlm.nih.gov/18279551/
Comment: https://doi.org/10.1017/s0007114508994411
Reply: https://doi.org/10.1017/S0007114508994423

Hemilä H, Kaprio J, Pietinen P, Albanes D, Heinonen OP.
Vitamin C and other compounds in vitamin C rich food in relation to risk of tuberculosis in male smokers.
Am J Epidemiol 1999;150:632-641
https://doi.org/10.1093/oxfordjournals.aje.a010062
https://pubmed.ncbi.nlm.nih.gov/10490003/

Tetanus

One study in Bangladesh found significant benefit of vitamin C for tetanus patients, see analysis in:
Hemilä H, Koivula TT
Vitamin C for preventing and treating tetanus.
Cochrane Database Syst Rev 2013; CD006665
https://hdl.handle.net/10138/225863
https://doi.org/10.1002/14651858.cd006665.pub3
https://www.mv.helsinki.fi/home/hemila/CT/2013_Coch_Tetanus_CD006665.pdf
https://pubmed.ncbi.nlm.nih.gov/24226506/

References to the review:
https://www.mv.helsinki.fi/home/hemila/CT/

Hemilä H. Vitamin C and tetanus. Annals of African Medicine 2010;9:108-109
https://doi.org/10.4103/1596-3519.64742

Other infections

Hemilä H.
Vitamin C and infections
Nutrients 2017;9(4):339.
https://doi.org/10.3390/nu9040339
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5409678/
References to the 2017 review,
updated in 2025. Many free links avoiding paywalls.
https://www.mv.helsinki.fi/home/hemila/N2017

Hemilä H. Infections in animals.
In: Do vitamins C and E affect respiratory infections? Thesis 2006 pp. 7-9
https://doi.org/10.5281/zenodo.6395595
https://hdl.handle.net/10138/20335
https://www.researchgate.net/publication/35439490

Book chapters

Hemilä: vitamin C and infections:
https://www.mv.helsinki.fi/home/hemila/H/1997_Hemila.pdf
https://www.mv.helsinki.fi/home/hemila/H/1998_Hemila_Eng.pdf