Department
of Public Health
University of Helsinki,
Finland
harri.hemila@helsinki.fi
https://www.mv.helsinki.fi/home/hemila
Feb
13, 2025
The
impact of Linus
Pauling in
the initiation of the series of
controlled trials in the 1970s:
see a brief summary with links
at:
https://www.mv.helsinki.fi/home/hemila/pauling
For the problems
in flawed meta-analyses and reviews
on
vitamin C and the common cold, see summaries
at:
https://www.mv.helsinki.fi/home/hemila/flawed_vitC_colds.htm
The
papers on the common cold are divided in categories and if the same
paper falls into several categories, it is listed in each of them
On
Jan 2025,
this review had the Altmetric score 4427
https://cochrane.altmetric.com/details/1229303
On
Oct 2022, this review had the Altmetric score 3382, which was
position 1439 out of all the 22,246,158 outputs, and 5th of the
Cochrane
reviews:
https://www.mv.helsinki.fi/home/hemila/AltmetricVitC_Colds_2022Oct.htm#score
Hemilä
H, Chalker E.
Vitamin
C for preventing and treating the common cold.
Cochrane
Database Syst Rev 2013;
CD000980
https://pmc.ncbi.nlm.nih.gov/articles/PMC8078152
https://hdl.handle.net/10138/225864
https://www.researchgate.net/publication/273209193
https://doi.org/10.1002/14651858.cd000980.pub4
https://www.mv.helsinki.fi/home/hemila/CC/2013_Coch_Colds_CD000980.pdf
https://www.ncbi.nlm.nih.gov/pubmed/23440782
References
to the
review:
https://www.mv.helsinki.fi/home/hemila/CC
Commentaries
on ‘Vitamin C for Preventing and Treating the Common Cold’ with a
response from the review author
[Reply to Bax, Spee and Madderom].
[Reply to Shamseer and Vohra].
Evidence-Based Child Health: A Cochrane Review Journal
2008;3:724-728
https://hdl.handle.net/10138/228088
https://www.researchgate.net/publication/244785237
https://doi.org/10.1002/ebch.261
https://www.mv.helsinki.fi/home/hemila/H/2008_L_EBCH.pdf
Hemilä
H, Chalker E.
Vitamin
C for the common cold and pneumonia.
Pol
Arch Intern Med. 2025
https://pubmed.ncbi.nlm.nih.gov/39803741
Hemilä
H, Chalker E.
Vitamin
C reduces the severity of common colds: a meta-analysis.
BMC
Public Health. 2023
https://pubmed.ncbi.nlm.nih.gov/38082300
Summary
of vitamin C, vitamin E, zinc lozenge studies on the common
cold:
Hemilä
H.
Vitamins
and minerals [book
chapter].
In: "Common cold " (Eccles R, Weber O,
eds.) Birkhauser Verlag, 2009:275-307
Abstract
and
references:
https://www.mv.helsinki.fi/home/hemila/birkhauser
Available
at:
https://doi.org/10.1007/978-3-7643-9912-2_13
https://doi.org/10.1007/978-3-7643-9912-2
A
manuscript version:
https://hdl.handle.net/10138/228060
Douglas
RM, Hemilä H. Vitamin
C for preventing and treating the common cold.
PLoS
Med
2005;2:e168
https://doi.org/10.1371/journal.pmed.0020168
https://www.ncbi.nlm.nih.gov/pmc/articles/pmc1160577/
Hemilä
H. Vitamin
C, respiratory infections, and the immune system.
Trends
Immunol
2003;24:579-580
https://doi.org/10.1016/j.it.2003.09.004
https://www.ncbi.nlm.nih.gov/pmc/articles/pmc7129436/
Hemilä
H, Douglas RM. Vitamin
C and acute respiratory infections.
Int
J TB Lung Disease
1999;3:756-761
https://www.ingentaconnect.com/content/iuatld/ijtld/1999/00000003/00000009/art00004
https://www.mv.helsinki.fi/home/hemila/H/HH_1999_IJTLD.pdf
Although
there is strong evidence that vitamin C does not
decrease
the averge incidence of colds in the general community, there is
strong evidence that some sub-populations benefit of vitamin C, so
that colds are prevented in them:
Hemilä
H. Prophylactic
benefit of vitamin C in large trials (Table 20).
In:
Do vitamins C and E affect respiratory infections? Thesis 2006 pp.
44
https://hdl.handle.net/10138/20335
https://doi.org/10.5281/zenodo.6395595
https://www.researchgate.net/publication/35656439
Strong
evidence that in some conditions males and females differ:
Hemilä
H. Vitamin
C and sex differences in respiratory tract infections.
Respir
Med 2008;102:625-626
https://hdl.handle.net/10138/228090
https://www.researchgate.net/publication/5628489
https://doi.org/10.1016/j.rmed.2007.12.011
https://www.mv.helsinki.fi/home/hemila/H/2008_L_RespMed.pdf
Effects
of vitamin C on military personnel may be explained by heavy physical
stress and crowding of people:
Hemilä
H. Vitamin
C supplementation and respiratory infections: a systematic review.
Mil
Med 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
Dietary
vitamin C had no correlation with common cold incidence in
middle-aged male smokers
Hemilä
H, Kaprio J, Albanes D, Heinonen OP, Virtamo J.
Vitamin
C, vitamin E and beta-carotene in relation to common cold incidence
in male smokers.
Epidemiology
2002;13:32-37
https://hdl.handle.net/10138/18059
https://doi.org/10.1097/00001648-200201000-00006
https://www.jstor.org/pss/3703244
Studies
with males in the UK found decrease in common cold incidence; the
explanation may be low dietary vitamin C intake when the trials were
carried out:
Hemilä
H. Vitamin
C intake and susceptibility to the common cold.
Br
J Nutr 1997;77:59-72 [Discussion in: 1997;78:857-866, see
below]
https://hdl.handle.net/10138/223362
https://www.researchgate.net/publication/14153016
https://doi.org/10.1017/s0007114500002889
https://www.mv.helsinki.fi/home/hemila/H/HH_1997_BJN.pdf
Discussion:
Hemilä H. Vitamin
C intake and susceptibility to the common cold – Reply.
Br J Nutr 1997;78:861-866
https://hdl.handle.net/10138/223364
https://doi.org/10.5281/zenodo.14610440
https://www.researchgate.net/publication/28369859
https://doi.org/10.1079/BJN19970201
https://www.mv.helsinki.fi/home/hemila/H/HH_1997_BJN2.pdf
Another
presentation of the UK study findings:
Hemilä
H. Prophylactic
effect of vitamin C on recurrent colds in the UK trials (Table
22).
In:
Do vitamins C and E affect respiratory infections? Thesis 2006 pp.
46-47
https://hdl.handle.net/10138/20335
https://doi.org/10.5281/zenodo.6395595
https://www.researchgate.net/publication/35656439
The
first meta-analysis on the effect of vitamin C on people under heavy
short-term physical stress which was based on 3 RCTs
Hemilä
H. Vitamin
C and common cold incidence: a review of studies with subjects under
heavy physical stress.
Int
J Sports Med 1996;17:379-383
https://hdl.handle.net/10138/225881
https://www.researchgate.net/publication/14347859
https://doi.org/10.1055/s-2007-972864
https://www.mv.helsinki.fi/home/hemila/H/HH_1996_IJSM.pdf
1
g/day of vitamin C does not prevent colds:
Hemilä
H. Does
vitamin C alleviate the symptoms of the common cold? A review of
current evidence.
Scand
J Infect Dis
1994;26:1-6
https://www.researchgate.net/publication/15008493
https://hdl.handle.net/10250/8077
https://doi.org/10.3109/00365549409008582
https://www.mv.helsinki.fi/home/hemila/H/HH_1994.pdf
1
g/day of vitamin C does not prevent colds:
Hemilä
H. Vitamin
C and the common cold.
Br
J Nutr 1992;67:3-16
https://hdl.handle.net/10138/223363
https://www.researchgate.net/publication/259425819
https://doi.org/10.1079/BJN19920004
https://www.mv.helsinki.fi/home/hemila/H/HH_1992.pdf
Vitamin
C has greater effect on
common
cold severity than on common cold duration
Hemilä
H, Chalker E.
Vitamin
C reduces the severity of common colds: a meta-analysis.
BMC
Public Health. 2023
https://pubmed.ncbi.nlm.nih.gov/38082300
Vitamin
C halved the duration of colds in male adolescent swimmers but not in
female adolescent swimmers:
Constantini
NW, Dubnov-Raz G, Eyal BB, Berry EM, Cohen AH, Hemilä H.
The
effect of vitamin C on upper respiratory infections in adolescent
swimmers: a randomized trial.
Eur
J Pediatrics 2011;170:59-63
https://hdl.handle.net/10138/228085
https://www.academia.edu/17790460
https://doi.org/10.1007/s00431-010-1270-z
https://www.mv.helsinki.fi/home/hemila/H/HH_2011_EurJPediatr.pdf
Effects
of vitamin C on military personnel may be explained by heavy physical
stress or/and crowding of people:
Hemilä
H. Vitamin
C supplementation and respiratory infections: a systematic review.
Mil
Med 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
On
average the benefit of vitamin C has been greater in adults than in
children, and with a dose of >=2 g/day compared with 1
g/day.
Hemilä
H. Vitamin
C supplementation and common cold symptoms: factors affecting the
magnitude of the benefit.
Med
Hypotheses 1999;52:171-178
https://hdl.handle.net/10138/223761
https://www.researchgate.net/publication/12959141
https://doi.org/10.1054/mehy.1997.0639
https://www.mv.helsinki.fi/home/hemila/H/HH_1999_MH.pdf
1
g/day of vitamin C shortens and alleviates colds:
Hemilä
H. Does
vitamin C alleviate the symptoms of the common cold? A review of
current evidence.
Scand
J Infect Dis 1994;26:1-6
https://hdl.handle.net/10250/8077
https://www.researchgate.net/publication/15008493
https://doi.org/10.3109/00365549409008582
https://www.mv.helsinki.fi/home/hemila/H/HH_1994.pdf
1
g/day of vitamin C shortens and alleviates colds:
Hemilä
H. Vitamin
C and the common cold. Br
J Nutr 1992;67:3-16
https://hdl.handle.net/10138/223363
https://www.researchgate.net/publication/259425819
https://doi.org/10.1079/BJN19920004
https://www.mv.helsinki.fi/home/hemila/H/HH_1992.pdf
Hemilä
H. Vitamin
C and common cold-induced asthma: a systematic review and statistical
analysis.
Allergy,
Asthma Clin Immunol
2013;9:46
https://doi.org/10.1186/1710-1492-9-46
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4018579
Hemilä
H. Vitamin
C and the common cold; Meta-analysis; Pauling's meta-analyses
(1971a,b);
In:
Do vitamins C and E affect respiratory infections? Thesis 2006 pp.
11-13,
28,
35-36
https://hdl.handle.net/10138/20335
https://doi.org/10.5281/zenodo.6395595
https://www.researchgate.net/publication/35656439
Hemilä
H. Vitamin
C supplementation and the common cold - was Linus Pauling right or
wrong?
Int
J Vitam Nutr Res
1997;67:329-335
https://doi.org/10.5281/zenodo.6406111
https://hdl.handle.net/10250/7980
https://www.mv.helsinki.fi/home/hemila/H/HH_1997_IJVNR.pdf
https://www.ncbi.nlm.nih.gov/pubmed/9350474
See other page for further links:
https://www.mv.helsinki.fi/home/hemila/flawed_vitC_colds.htm
Hemilä
H. Shortcomings
in the vitamin C and common cold meta-analysis by Ran et al. (2018)
Pubpeer
2021
https://pubpeer.com/publications/077EAB95E9141BE6A455C30F0A688E#1
Comments
on the following
meta-analysis:
https://doi.org/10.1155/2018/1837634
https://www.ncbi.nlm.nih.gov/pmc/articles/pmc6057395/
Because of the severe flaws, the Ran et al. review was retracted in 2023:
Retracted:
Extra
dose of vitamin C based on a daily supplementation shortens the
common cold:
a meta-analysis of 9 randomized controlled trials.
Biomed Res Int. 2023; 2023: 9848057
https://doi.org/10.1155/2023/9848057
https://pmc.ncbi.nlm.nih.gov/articles/PMC10110384
Hemilä H,
Chalker E. Meta-analysis
on vitamin C and the common cold in children may be misleading.
Eur J Clin Pharmacol. 2019
https://hdl.handle.net/10138/318103
https://doi.org/10.1007/s00228-019-02733-x
https://www.mv.helsinki.fi/home/hemila/H/Vorilhon_2019_Problems.pdf
https://www.mv.helsinki.fi/home/hemila/H/Vorilhon_2019_Problems_Supplement.pdf
https://doi.org/10.5281/zenodo.6395643
This is
comment on:
Vorilhon
P,
et al. Efficacy of vitamin C for the prevention and treatment of
upper respiratory tract infection. A meta-analysis in children. Eur J
Clin Pharmacol. 2019
https://doi.org/10.1007/s00228-018-2601-7
Further
severe problems in the Vorilhon meta-analysis are describe in this
document:
https://hdl.handle.fi/10138/333365
https://doi.org/10.5281/zenodo.6395731
Because
of the severe flaws, the Vorilhon meta-analysis was retracted
in 2021:
Vorilhon
P et
al.
Retraction
Note: Efficacy
of vitamin C for the prevention and treatment of upper respiratory
tract infection. A meta-analysis in children. Eur J Clin Pharmacol.
2021
Jun;77(6):941.
https://pubmed.ncbi.nlm.nih.gov/33988724/
https://doi.org/10.1007/s00228-021-03150-9