Talk:Zinc and the common cold/Archive 1

Continuation of original AfC discussion

 * Thank you for putting inline citation into the lead.
 * Primary sources are discouraged by the guideline delineated on WP:MEDRS. The rational behind this is discussed in detail on that page. This policy is the result of a period of evolution after several years of community discussion. If you disagree with that policy, the correct place to raise your concerns would be on the talk page for the guideline. While that guideline stands however, please let me assure you that the primary sources need to be removed, and if possible replaced with reliable secondary and tertiary sources. If no replacement sources are available, then the content is not notable [yet] for wikipedia. This does not mean that the content is irrelevant on a wider stage (e.g. in scientific circles), but Wikipedia has guidelines for what is notable enough for inclusion in the encyclopedia entries. I include a brief sweep to move the discussion forwards below. Main issues appear to be 1. primary sources, 2. WP:MEDDATE, 3. otherwise unreliable sources 4. possible conflict of interest (?). Many thanks, Lesion  ( talk ) 12:19, 24 October 2013 (UTC)


 * Hirt M, Nobel S, Barron E (2000) Zinc nasal gel for the treatment of common cold symptoms: a double-blind, placebo-controlled trial. Ear Nose Throat J 79:778-82 primary source
 * Mossad SB (2003) Effect of zincum gluconicum nasal gel on the duration and symptom severity of the common cold in otherwise healthy adults. QJM 96:35-43 primary source
 * Pories WJ, et al. (1967) Acceleration of healing with zinc sulfate. Ann Surg 165:432-6 primary source, WP:MEDDATE issue
 * Simkin PA (1976) Oral zinc sulphate in rheumatoid arthritis. Lancet 2:539-42 primary source, MEDDATE issue
 * Samman S, Roberts DC (1987) The effect of zinc supplements on plasma zinc and copper levels and the reported symptoms in healthy volunteers. Med J Aust 146:246-9 primary source, MEDDATE issue
 * Forman WB, et al. (1990) Zinc abuse--an unsuspected cause of sideroblastic anemia. West J Med 152:190-2 Case report, MEDDATE issue
 * Fiske DN, et al. (1994) Zinc-induced sideroblastic anemia: report of a case, review of the literature, and description of the hematologic syndrome. Am J Hematol. 46:147-50 Case report, MEDDATE issue
 * Eby GA, Davis DR, Halcomb WW (1984) Reduction in duration of common cold by zinc gluconate lozenges in a double-blind study. Antimicrob Agents Chemother 25:20-4 primary source, MEDDATE issue
 * Godfrey JC (1988) Zinc for the common cold. Antimicrob Agents Chemother 32:605-6 although not a primary source, this is a bit old, and also it is a letter to the editor, it is better to use review papers.
 * Eby GA (1988) Stability constants of zinc complexes affect common cold treatment results. Antimicrob Agents Chemother 32:606-7 as above
 * Eby GA (2001) Elimination of efficacy by additives in zinc acetate lozenges for common colds. Clin Infect Dis 32:1520 this appears to be a comment on a previous primary source
 * Prasad AS, et al. (2008) Duration and severity of symptoms and levels of plasma interleukin-1 receptor antagonist, soluble tumor necrosis factor receptor, and adhesion molecules in patients with common cold treated with zinc acetate. J Infect Dis 197:795-802 primary source
 * Farr BM, Gwaltney JM (1987) The problems of taste in placebo matching: an evaluation of zinc gluconate for the common cold. J Chronic Dis 40:875-9 MEDDATE issue
 * Smith DS, et al. (1989) Failure of zinc gluconate in treatment of acute upper respiratory tract infections. Antimicrob Agents Chemother 33:646-8 primary source, MEDDATE issue
 * http://coldcure.com/html/zinc-lozenges.html unreliable medical source, self published, promotional, unreferenced, no peer review ... definitely needs to be removed
 * Jafek BW, Linschoten MR, Murrow BW (2004) Anosmia after intranasal zinc gluconate use. Am J Rhinol 18:137-41 case report
 * Alexander TH, Davidson TM (2006) Intranasal zinc and anosmia: the zinc-induced anosmia syndrome. Laryngoscope 116:217-20 primary source
 * Eby G (2012) The mouth-nose biologically closed electric circuit in zinc lozenge therapy of common colds as explanation of rapid therapeutic action. Expert Rev Respir Med 6:251-2 letter to the editor

These souces are likely ok, not sure how others feel:
 * Bakar NKA, Taylor DM, Williams DR (1999) The chemical speciation of zinc in human saliva: possible correlation with reduction of the symptoms of the common cold produced by zinc gluconate-containing lozenges. Chemical Speciation and Bioavailability 11:95-101 '''apart from breaching MEDDATE, this appears to be a secondary source since it is based on 7 primary sources. Suitable to stay imo
 * Eby GA (2004) Zinc lozenges: cold cure or candy? Solution chemistry determinations. Biosci Rep 24:23-39 as above
 * Eby GA (2010) Zinc lozenges as cure for the common cold. Med Hypotheses 74:482-92 as above, but I am not confident to say medical hypotheses is a reliable journal, not come across this issue before on wikipedia but I was aware of the journal.
 * Hemilä H (2011) Zinc lozenges may shorten the duration of colds: a systematic review. Open Respir Med J 5:51-8 OK
 * Jackson JL, Lesho E, Peterson C (2000) Zinc and the common cold: a meta-analysis revisited. J Nutr 130(5S Suppl):1512S-5S OK
 * Thompson SG (1994) Why sources of heterogeneity in meta-analysis should be investigated. BMJ 309:1351-5 a bit old, but OK
 * Caruso TJ, Prober CG, Gwaltney JM (2007) Treatment of naturally acquired common colds with zinc. Clin Infect Dis 45:569-74 OK
 * Hemilä H (2013) Zinc and the common cold: problems in the review by Caruso et al. (2007) OK, I think
 * Singh M, Das RR (2013) Zinc for the common cold. Cochrane Database Syst Rev CD001364 ideal, but not the latest version of the review
 * Hemilä H (2011) The zinc for the common cold review by Singh and Das has a number of problems OK
 * Science M, et al. (2012) Zinc for the treatment of the common cold: a systematic review and meta-analysis of randomized controlled trials. CMAJ 184:E551-61 OK
 * Hemilä H (2012) Zinc acetate lozenges may shorten common cold duration by up to 40%, CMAJ version: http://www.cmaj.ca/content/184/10/E551/reply#cmaj_el_706238 OK, I think
 * Novick SG, et al. (1996) How does zinc modify the common cold? Clinical observations and implications regarding mechanisms of action. Med Hypotheses 46:295-302 slight MEDDATE issue, and medical hypotheses journal again, but probably OK

I will do my best to take time and go through the comments above and the references within a week. Hhemila (talk) 08:07, 25 October 2013 (UTC)


 * I've had a general edit and removed some primary & out-of-date sources, lessened undue dwelling on certain sources, template-ized the refs, introduced some tertiary commentary, removed some original research and synthesis and generally tidied-up. Hope this helps ... Alexbrn talk 16:56, 25 October 2013 (UTC)


 * There is wp:NODEADLINE, it's better to to this right than fast. Given the availability of recent high-quality sources, I see no point in using older ones except perhaps in a historical context.  Medical assertions should be backed by the best-quality (recent, independent, secondary) sources. Given the availability of CD001364.pub4 and CMAJ 184:E551-61 I see no justification for using older sources in any way that would seem to impeach those two. Certainly the published criticisms (by Eby and by Hemila) to the latter paper are interesting reads, and even appear to be justified, but they do not meet wp:MEDRS. We can wait for an independent source that does. Given the strength of the criticisms, one might have expected a fairly prompt response by Science, but it has now been more than a year since the criticisms were posted.
 * To my reading, the most important content in the Cochrane review was the assessment of evidence quality. Aside from the evidence on side effects, the rest was all of low or very low GRADE. Essentially this says to me "we have no useful evidence to assess". Is there some dispute over this that I've missed? LeadSongDog come howl!  17:23, 25 October 2013 (UTC)
 * I think this piece from NHS Choices (which I have now included in our article) gives a really good overview of the situation, with reference to the recent reviews. I'd be very happy to see our article's POV align with the (neutral) POV here. Alexbrn talk 18:02, 25 October 2013 (UTC)

Wikipedia principles are not followed in the editings 25 October 2013
Among three core principles, Wikipedia has the following two:

1) The references must be reliable: https://en.wikipedia.org/wiki/Wikipedia:Verifiability https://en.wikipedia.org/wiki/Wikipedia:MEDRS

2) There should be neutral presentation of the topics: “Editing from a neutral point of view (NPOV) means representing … all of the significant views that have been published by reliable sources on a topic... NPOV is a fundamental principle of Wikipedia. https://en.wikipedia.org/wiki/Wikipedia:Neutral_point_of_view

Editings and comments by Alexbrn and LeadSongdog are not consistent with the two principles.

CD001364 (Cochrane review on Zinc and the common cold) is seriously flawed as I showed in a 10-point feedback of the 2011 version. My feedback was published inside the Cochrane review and it is separately available at our university repository as an easier to read layout: http://hdl.handle.net/10138/39188 Authors of the Cochrane review have not replied to my criticism and they have taken only minor parts of it into account in the 2013 update so that most of the criticism is still valid. CMAJ 184:E551-61 (a me-too copy of the above Cochrane review) has similar serious flaws (obviously, as it is a me-too copy) which I pointed out in a 7-point commentary published in CMAJ pages: http://www.cmaj.ca/content/early/2012/05/07/cmaj.111990.abstract/reply#cmaj_el_706238 which is also available at our university repository in an easier to read layout: http://hdl.handle.net/10138/40083 Authors of the CMAJ review have not replied to my criticisms. A criticism is valid until it is refuted and therefore my criticism of the CMAJ review is still valid. Thus, both of those two reviews are NOT reliable.

Reliability of a source is not defined by the forum in which it is published, but it is defined by the internal characteristics of the source. There are several studies published in top journals such as Science and Nature that have been shown to be fraudulent so that being a source in Science or Nature is not, per se, a proof that the source is reliable. When the Cochrane review and the CMAJ review have been shown to be flawed, they are not reliable sources.

Wikipedia instructions do acknowledge this problem: https://en.wikipedia.org/wiki/Wikipedia:MEDSCI “... the fact that a claim is published in a refereed journal need not make it true...” Therefore Alexbrn and Leadsongdog do not follow the requirement of reliability.

In the text version which I initially prepared, those two reviews were mentioned, but I gave references to the criticisms. That procedure is following the “neutral point of view approach”. In such a case the reader may decide himself or herself whether the CMAJ review and the Cochrane review are reasonable, or whether the reader decides to take a closer look at the claimed problems of those two reviews. That is writing with the neutral point of view. The reader is given "all significant views".

Alexbrn and Leadsongdog deleted the criticism against the CMAJ review and the Cochrane review and thereby prevent the reader from seeing that those reviews have been heavily criticised.

Leadsongdog writes that “we have no useful evidence to assess”. That is a very strange comment. All 13 zinc lozenge comparisons which I analyzed in my own meta-analysis were double-blind and placebo-controlled trials, and all but one were randomized. The only one that was not randomized did not find find benefit of zinc lozenges and therefore it cannot bias the total evidence towards benefit. All the high dose zinc acetate trials were randomized, double-blind and placebo-controlled and there were very few drop-outs. What is the basis for Leadsongdog's opinion that there is no useful evidence. If randomized, double-blind, placebo-controlled trials with few drop-outs is “no useful evidence” what is the evidence he or she expects in medicine?

I do not start an edit war with Alexbrn and Leadsongdog.

If there is someone who might like to see my brief version of the zinc lozenges and the common cold field, he or she can look at my last version available in wikipedia at: https://en.wikipedia.org/w/index.php?title=Zinc_and_the_common_cold&oldid=578590771 I am satisfied with it, although I had planned to revise it according the the instructions by Lesion above.

If wikipedia readers do prefer simplistic “NHS Choices” and “WebMD” type of sources with extracted statements such as “According to WebMD, studies carried out on zinc treatments for colds have produced mixed results. They say that experts are agreed that any benefit zinc brings is 'very minor' ” (version 26 Oct) - lets leave the version based on such sources. Those are not “secondary sources” and not “tertiary sources” in the Wikipedia language: https://en.wikipedia.org/wiki/Wikipedia:MEDRS

I had assumed that average readers of Wikipedia might have been interested in the question "what have the placebo-controlled studies actually found?". I showed what the findings actually are with a figure based on a "secondary source" in Wikipedia language. If the readers want opinions through WebMD service, instead of the actual study findings, let them read opinions.

Hhemila (talk) 16:15, 26 October 2013 (UTC)


 * Hi there! We need to follow the most reliable sources. CMAJ and Cochrane are publications with an extremely good reputation, and the NHS and WebMD are useful in summarizing their findings, giving us a handy layer of independent sourcing over that. Wikipedia conservatively reflects the mainstream consensus view and if that's "wrong" well, then the reliable sources will in time change and Wikipedia will follow them. You can see, surely, that if editors were permitted to challenge the mainstream consensus view with minority positions, the project would fall apart. WP:VNT is an interesting essay around this topic ... Alexbrn talk 16:35, 26 October 2013 (UTC)
 * Indeed. Many experts undergo some culture shock when they arrive to wikipedia editing. This is "The encyclopedia that anyone can edit." Most, but not all, of that "anyone" refers to pseudonymous users, of no provable authority, expertise, or academic integrity. That is a major reason that WP endeavors not to include original work, per wp:NOR. Instead, the ability of a user to trust what they read hinges on the citation of credibly published source documents. We avoid reference to primary sources because their authors are frequently inclined to believe their work is better and more significant than others do. It is a form of conflict of interest, however benign. Instead, we use independent secondary reviews, since their authors are in a better position to be objective. LeadSongDog  come howl!  18:47, 29 October 2013 (UTC)


 * Hi! Although the final paragraph in Effectiveness __The only review to consider the effects of the amount of the active ingredient, ionic zinc (iZn)__ is extremely interesting and would lead me (The Lay Man With No Medical Education) to research further, it reads as more opinion than a fact.  It's also an obvious  Conflict Of Interest  as the author of  this edit,   Georgeeby  appears to  site his/herself as a reference .  Can this paragraph be rewritten for Neutrality and the removal of the Conflict of interest, yet retain this very interesting information?  I feel that this paragraph is an argument for a specific viewpoint, not a neutral statement. Flipmcf (talk) 23:25, 3 January 2014 (UTC)
 * There was a discussion with Georgeeby on talk:Herpes simplex about this same issue. Lesion  ( talk ) 01:53, 4 January 2014 (UTC)

Suggested edits
Although I see in Wikipedia:MEDRS that WebMD is considered a reliable, peer-reviewed non-primary source for articles, I am disappointed to see the incorrect characterization of 'several' cases of loss of sense of smell due to intranasal zinc use. A hopefully non-controversial fix here is to instead pull references from the page on Zicam which correctly mention hundreds of cases of anosmia reported to the FDA and to the manufacturer of Zicam. On a side note, according to community standards should the Zicam article be linked to from this article (maybe not, because it's homeopathic)?

It's also disappointing to see WebMD's dismissive characterization of zinc's effectiveness quoted in the lead and elaborated later. WebMD does not seem to provide a reference for this information. Further, this seems to disagree with other sources such as [3], "...people taking zinc had cold symptoms for an average of one to two days less than patients given a placebo treatment...", but is presented as qualifier rather than a contrasting viewpoint.

The last sentence in background makes an assumption that gets to the core of the conflict in reporting on zinc research in Wikipedia: "...the results, while suggestive of a positive effect, have not been conclusive, since no consideration was given to the amount of the active ingredient..." This statement implies that the results would be conclusive if the amount of active ingredient was taken into account, and consequently asserts a single critical study design flaw and assumes the outcome of a 'correct' study. Contrast this with the cited source's statement, "...differences between trials in terms of design, dosages, timing and age of participants make this result less reliable.", which does not imply a single flaw in the analysis. The last sentence in effectiveness is also problematic: it assumes that iZn is the active ingredient, without calling out that controversy exists over in what form zinc is effective.

To attempt a productive generalization about the conflicts in editing going on here, the minority point of view and hypothesis is that (only ionic, in solution) zinc works against the cold via the presence of ionic zinc in solution in the mouth and throat, whereas the community consensus is that there is no consensus. If we entertain the minority hypothesis, the lack of consensus is unsurprising given that no systematic reviews are being included here which are designed to actually test the minority hypothesis. Instead (such as the 2011 Cochrane review) they don't even differentiate between zinc as a dietary supplement and as an immediate treatment for the cold, and ignore things like the formulation used. Is there a more direct and appropriate way to inform readers of this issue in the article, or is it not appropriate for Wikipedia until it is settled in scientific circles? --eecharlie 13:41, 3 November 2014 (UTC) — Preceding unsigned comment added by Eecharlie (talk • contribs)

Cochrane Review "Zinc for the common cold" has been withdrawn
The Cochrane Review "Zinc for the common cold" has been withdrawn due to concerns regarding the calculation and analysis of data in the review. Zinc for the common cold-Withdrawn So, I removed the sentence from the article that was entirely based on this review. Someone with more knowledge of the topic should look over the paragraph and edit it for better clarity. Sydney Poore/FloNight&#9829;&#9829;&#9829;&#9829; 18:33, 22 July 2015 (UTC)

Hemila keeps publishing reviews
Hemila et al continue to publish reviews:

Hemilä H. Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage. JRSM Open. 2017 May 2;8(5):2054270417694291. doi: 10.1177/2054270417694291. eCollection 2017 May. PubMed PMID: 28515951.

Hemilä H. Duration of the common cold and similar continuous outcomes should be analyzed on the relative scale: a case study of two zinc lozenge trials. BMC Med Res Methodol. 2017 May 12;17(1):82. doi: 10.1186/s12874-017-0356-y. PubMed PMID: 28494765.

Hemilä H, Fitzgerald JT, Petrus EJ, Prasad A. Zinc Acetate Lozenges May Improve the Recovery Rate of Common Cold Patients: An Individual Patient Data Meta-Analysis. Open Forum Infect Dis. 2017 Apr 3;4(2):ofx059. doi:10.1093/ofid/ofx059. eCollection 2017 Spring. PubMed PMID: 28480298.

Hemilä H, Petrus EJ, Fitzgerald JT, Prasad A. Zinc acetate lozenges for treating the common cold: an individual patient data meta-analysis. Br J Clin Pharmacol. 2016 Nov;82(5):1393-1398. doi: 10.1111/bcp.13057. Epub 2016 Jul 28. PubMed PMID: 27378206. — Preceding unsigned comment added by David notMD (talk • contribs) 15:53, 23 August 2017 (UTC)
 * Yes and we should use some of these. Doc James  (talk · contribs · email) 14:40, 8 January 2018 (UTC)

The problem with "significant"
To normal people this term mean "a large amount" or a "meaningful effect"

In research it means that the value in question has less than a 5% chance of being simple random chance. It does not mean that it is meaningful.

Doc James (talk · contribs · email) 02:33, 12 January 2018 (UTC)


 * Why do you think I don't know that? I'm a statistician...  Seppi  333  (Insert 2¢) 04:09, 12 January 2018 (UTC)
 * Was me explaining this edit of mine. Was not specifically directed at you :-) Doc James  (talk · contribs · email) 22:10, 15 January 2018 (UTC)

"are commonly used"
User:Seppi333 which ref supports this? Doc James (talk · contribs · email) 02:31, 12 January 2018 (UTC)
 * The 1st lead sentence isn't referenced.  Seppi  333  (Insert 2¢) 04:09, 12 January 2018 (UTC)
 * Do you think the statement I quoted in this edit summary is adequate for supporting the current 1st lead sentence?  Seppi  333  (Insert 2¢) 03:37, 15 January 2018 (UTC)
 * "Zinc is also found in many cold lozenges and some over-the-counter drugs sold as cold remedies." does not really say it is commonly used just that it occurs in many OTC cold remedies in the US.
 * How often are "OTC cold remedies" used is the question? Doc James  (talk · contribs · email) 22:10, 15 January 2018 (UTC)
 * Not sure, although I imagine that there's publicly available annual sales data for individual products.  Seppi  333  (Insert 2¢) 23:31, 15 January 2018 (UTC)

Stray brackets
Your last edit to this article introduced a pair of stray brackets to the 1st lead sentence, which remained there for 3 weeks. Please be more careful when you edit.  Seppi  333  (Insert 2¢) 22:23, 21 March 2018 (UTC)

Medical Hypothesis
WP:MEDRS says "Still others, such as Medical Hypotheses, publish speculative proposals that are not reliable sources for biomedical topics." Doc James (talk · contribs · email) 23:26, 15 January 2018 (UTC)


 * The problem is that this is from PubMed. PubMed is one of the most reliable secondary medical sources on the net. WP:MEDRS doesn't apply in this context because of the fact that while the paper itself is a "hypothisis" as a primary source, it is NOT a "hypothisis" to the extent that it cites other research as a secondary source (Where the citation should be perhaps in the format of X source citing Y source to have been a bit more clear), where WP:MEDRS states that secondary sources are to be respected. 67.78.69.82 (talk) 23:49, 12 November 2018 (UTC)
 * pubmed is not any kind of "source" - it is just an index, and it lists many works that are not OK per WP:MEDRS. See Pubmed if you like. Jytdog (talk) 04:58, 13 November 2018 (UTC)

Regular intake of Zinc
According to NHS' article on the Cochrane's Zinc review, regular intake of zinc of at least 5 months appears to result in people requiring less school absence leave and prescription antibiotics when they are sick. Cost-effectiveness for this would be a personal decision, however. KX Toh (talk) 07:06, 23 August 2019 (UTC) To add under effectiveness

Rhinovirus vs. coronavirus and COVID-19
This revert was justified as WP:OFFTOPIC because the article is about "zinc and the common cold", and the common cold virus is a rhinovirus (or many strains of them), with little evidence that coronavirus-derived COVID-19 is related to the common cold (estimated at 15% or less of the common cold). Further, this edit included a preliminary research report under the "Evidence" section, so is clearly premature and misleading to include as "evidence", so has been removed. There are no WP:MEDRS reviews to substantiate that zinc a) is useful specifically to treat COVID-19 disease or b) more broadly in the clinical literature that it is useful for reducing the symptoms of coronavirus infections. Zefr (talk) 16:07, 21 September 2020 (UTC)