Zinc – “Clinically proven”

Whether stated in an ad for conventional or alternative medicine, I typically take claims of “clinically proven” with a grain of salt. That’s because the statistical methodology used to “prove” these claims basically says “if we assume these claims aren’t true, then the results we have seen in studies would have been too bizarre.” This is even though advertisement language is regulated by the DSHEA(Dietary Supplement Health Education Act?), Food, Drug and Cosmetic Act, the Code of Federal Regulations Title 21 Part 101, and so forth. So, when I saw the words “clinically proven to cut your cold nearly in half” by the Cold-Eeze® product manufactured by the “Quigley Corporation”:http://www.quigleyco.com, I naturally got a bit curious.

Cold-Eeze is the homeopathic remedy Zincum Gluconicum along with inactive ingredients. The form I saw was a lozenge, and the dilution was 2X (i.e. a factor of 10^2^=100). The back of the box makes the following claim:

Two clinical studies have shown: Cold-Eeze proprietary formula reduces the duration and severity of cols by 42% or 3 to 4 days.

The independent double blind studies were conducted at the Cleveland clinic and Dartmouth College and published in peer-reviewed journals.

The two articles are as follows:
* Mossad, _et al._ ??Annals of Internal Medicine??. *126*:2, July 15, 1996. (“PubMed”:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=8678384&query_hl=1&itool=pubmed_docsum | “Full Text – free”:http://www.annals.org/cgi/content/full/125/2/81)
* Godfrey, _et al._ ??Journal of International Medicine Research??. *20*:3, June 1992. (“PubMed”:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=1397668&query_hl=3&itool=pubmed_docsum)

I don’t know that much about ??JIMR(Journal of International Medicine Research)??, but the ??AIM(Annals of Internal Medicine)?? is certainly one of the top-tier publications. (This means little in my book, but hey, we’re talking about one of the topics that James Randi has staked his $1 million prize on from my understanding.)

So, the Mossad article in ??AIM(Annals of Internal Medicine)?? does show a well-designed and well-controlled study of zincum gluconicum in which the severity of symptoms was reduced from a median of 7.6 days in the placebo group to a median of 4.4 days in the zincum gluconicum group. The full text is available, and this study makes it look like this formulation does reduce duration of symptoms. Do read the discussion section of the article to see the limitations of the study. No mention was made of the method of preparation of the active ingredient (i.e. dilution), and the discussion of mechanism was phrased in terms of clinical pharmacology rather than homeopathy. This may reflect a bias in the journal or the authors, or Quigley may have produced non-homeopathic zinc lozenges for the study. It’s also worth noting that on the box the company states that the active ingredient is a homeopathic cold remedy, but I didn’t see a mention of the Homeopathic Pharmacopoeia of the US.

The Godfrey article is not in full text online, but from the abstract it looks like zinc took 1.2 days or 4.9 days off the duration of symptoms, depending on when therapy was started. The formulation and treatment schedules were not discussed.

So, it does look like the Cold-Eeze product performed pretty well in those two studies, if in fact is was a similar formulation. However, what about other studies? Some seem to be more negative on zinc:
* Eby, GA and Halcomb, WW. ??Altern Ther Health Med.?? 2006 Jan-Feb;12(1):34-8. “We found no reason to recommend intranasal zinc gluconate or zinc orotate lozenges in treating common colds.” The measured number of patients free of symptoms after 7 days, and 10/16 (63%) in the zinc group compared with 9/17 (53%) in the placebo group. I actually find their conclusions bizarre in light of their sample size and measure. If they had wanted to detect a 20% difference between placebo and zinc, the study would have had 20% power. It’s pretty awful to have an underpowered study and then claim no difference when you can’t reject the null hypothesis. Heck, if we were allowed to do that, I could make it look like penicillin was ineffective. So I’d take the numbers from that study as a bit of information, but ignore the conclusions.
* Wintergerst, ES, _et al._ ??Ann Nutr Metab.?? 2006;50(2):85-94. Epub 2005 Dec 21. This is a review of done on zinc and vitamin C, basically as nutrients. The article does note that adequate amounts of zinc and vitamin C seem to shorten duration of symptoms.
* Arroll, B. ??Respir Med. 2005 Dec;99(12):1477-84.?? This Cochrane database review notes that zinc does seem to have some efficacy, and might be useful.

There are many others. A “PubMed search”:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed of “zinc treatment cold” (no quotes) returns 192 articles. Sorting through these studies and accounting for differences in formulation, dosing schedule, actual dose, delivery, and other factors that greatly affect drug efficacy is dizzying and daunting at best. It’s also important to remember that zinc lozenges do carry the potential for adverse events, such as bad taste and nausea.

Also not discussed in these articles are the issues of homeopathic dilution of zinc compounds. This is going to be hard to find because of the bias of journals, and because I still haven’t seen evidence that zinc is in the HPUS.

Finally, the long-term consequences of the suppression of common cold symptoms has not been discussed. Zinc has no effect on virus-shedding, so presumably it doesn’t help the body dump the cause of cold any faster. Whether reducing the severity of symptoms is, in the long run, useful, has not been answered.

For me, the jury is out on zinc as a cold remedy. It seems to do something. Exactly what, I want to understand a little bit better.

Technorati Tags: zinc, cold, homeopathy

More on Ayurveda

So, not long after I read Orac’s hit piece on alternative medicine about a very old JAMA article about mercury in Ayurvedic herbs manufactured in India and sold in the US, I read this entry on how the government of India is testing Ayurveda and trying to see how it fits with the world of modern medicine. Part of this process, of course, is Good Manufacturing Practices designed to ensure that what you manufacture (say, herbs suitable for Ayurveda) is what you say you manufacture (as opposed to, say, mercury-laden herbs or bone powder). But there’s more to this story.

Final thoughts on homeopathy before I leave it for a while

Rare medical advice from this site: don’t try a homeopathic remedy without first consulting a qualified practitioner of homeopathy. Since most homeopathic remedies are available OTC, it’s possible to self-diagnose and self-medicate. However, I’m finding through personal experience and through study that this isn’t effective, and any prevailing opinion I read on homeopathy advocacy sites seem to agree (at least when it comes to discussing the responder effect in studies). You seem to have to go through the process of consulting a homeopathic practitioner so that they can select the right remedy before you can receive the benefit.

The other thought is that I said something in a “previous post”:http://www.randomjohn.info/wordpress/2005/12/31/fda-regulation-of-homeopathic-remedies that can be construed as misleading. I said that the FDA regulates homeopathic remedies as OTC. This is true, except that pharmaceuticals have to face a long course of clinical study to become approved for prescription use, and, after some time on the market, the FDA may approve the safer ones for OTC use. Homeopathic remedies do not face this same kind of regulation, but they do face similar regulations for manufacture and labeling. Please see the “previous post”:http://www.randomjohn.info/wordpress/2005/12/31/fda-regulation-of-homeopathic-remedies for details.

FDA regulation of homeopathic remedies

The FDA “regulates”:http://nccam.nih.gov/health/homeopathy/#q6 homeopathic remedies the same as OTC drugs. (See also the rest of the “NCCAM page”:http://nccam.nih.gov/health/homeopathy/ on homeopathy.)

(Note: please see my “new post”:http://www.randomjohn.info/wordpress/2006/01/04/final-thoughts-on-homeopathy-before-i-leave-it-for-a-while/ to clarify this. Homeopathic remedies are not subject to the same clinical development regulations as pharmaceuticals.)

As I drink a glass of water

So I’ve recently been bothered by the out-of-hand dismissal of homeopathy as a fancy and placebo effect, much like “drinking a glass of water”:http://oracknows.blogspot.com/2005/12/more-evidence-that-alternative.html, and I’ve decided to do a little more digging on my own.

First, let’s start with a “definition”:http://skepdic.com/placebo.html

bq. The placebo effect is the measurable, observable, or felt improvement in health not attributable to treatment.

If you are to believe the source and the quotations within, the placebo effect requires the belief that a treatment will make you better. Taken further, this suggests the care of a trusted practitioner, although some theories suggest natural improvement over time or “regression to the mean”:http://www.visi.com/~thornley/david/philosophy/thinking/mean.html.

If, for the sake of argument only, we assume that homeopathy acts mainly through the placebo effect (and I will question this assumption in a minute), then most theories of the placebo effect suggest that even then homeopathy is not the same as “drinking a glass of water.” Drinking a glass of water doesn’t involve the care of a trusted practitioner, and in most prevailing theories, does not equate to the placebo effect.

Data please: holding quackbusters to their own standards, Part II (Orac, you know)

On to the goods. Let’s start with the title: “More evidence that alternative medicine boosters don’t really want scientific evaluation of their therapies”:http://oracknows.blogspot.com/2005/12/more-evidence-that-alternative.html. Pretty heady title. Looks like we have a hypothesis here: “Alternative medicine boosters don’t really want scientific evaluation of their therapies.” And, presumably, what Orac presents is “evidence” in favor of this “hypothesis.”