So, have you survived or have you succumbed to the awful cold season that is upon us? I thought I'd follow-up my post on Vitamin C and the Common Cold with a post on another popular homeopathic cold remedy...zinc. Because of its role in assisting with immune function, it is no surprise that quite a few studies have evaluated the effectiveness of zinc for the treatment of colds. While its mechanism of action is still not clear, some investigators hypothesize that zinc plays a role in preventing the attachment and reproduction of rhinovirus, the most common cause of all colds, inside of the nose and suppressing the inflammation that is responsible for many of the awful symptoms.
When it comes to zinc and the common cold, it appears that the jury is still out. In a thorough review of research spanning 40 years that examined zinc as a cold remedy, investigators evaluated 14 of the highest quality studies conducted in this area. Of those, half of the studies found no effect of zinc lozenges or nasal sprays on the common cold while the other half found zinc lozenges and nasal gels beneficial for reducing the duration and/or severity of cold symptoms. Two other major review studies also concluded that the evidence is inconsistent but that further research is warranted (1,2).
Of the studies that have detected potential benefits from zinc for treatment of the common cold, I found a few interesting and possibly helpful pieces of information. Zinc lozenges in the form of zinc gluconate (aka, zinc gluconium) or zinc acetate taken every 2 hours while awake within 24 hours of the onset of symptoms (at the very first sign of the symptoms is best) may help reduce the duration of the cold symptoms by an average of about 3 days! It also appears that low doses (<9 mg of elemental zinc) are not as beneficial as higher doses (~9-24 mg). As for the nasal sprays and gels, I wouldn't suggest touching those with a ten foot pole for now as the U.S. Food and Drug Administration recently warned consumers to stop using such products due to numerous reports of anosmia (loss of sense of smell) that may be long-lasting or permanent! (Something I've been telling my students and clients for a long time!) Be forewarned, too, that anyone using zinc supplements should not consume greater than 40 mg/day as there are some negative side effects associated with excessive zinc consumption, which include: nausea, vomiting, loss of appetite, abdominal cramps, diarrhea, headaches, copper deficiency resulting in anemia, elevated cholesterol, and interestingly enough...impaired immune function. (Note that an individual could possibly experience some of these side effects given the typical dosages and treatment protocols of these types of supplements.)
If you're not so sure about taking the supplements and thinking, "Hey, maybe I can just boost my intake of zinc through food if I get a cold.", think again. Increasing our intake of zinc through food at the onset of a cold will not have the same effect as that of the zinc lozenges given the proposed mechanism of action that I discussed before. The rhinovirus is replicating in the nasal mucosa. Therefore, the zinc needs to be in close proximity to that area on a regular basis (every 2-3 hours) in order for it to possibly work, and food that's chewed and swallowed won't have the same effect.
So there you have it...the scoop on zinc-ing up when you come down with a cold, but you may still be asking yourself, "So, what should I do?" We have to ask a few important questions.
- Is this type of therapy more effective than mere suggestion or doing nothing? Possibly.
- Is it as safe as doing nothing? Maybe not.
- If there is a possibility of it being unsafe, does the potential for benefit exceed that of its potential harm? Maybe not.
- WWMD? (or What Would Michelle Do -- lol) Aw shoot, I admit it. I've taken zinc lozenges at the first hint of a cold. Call me desperate! In some cases, I believe it worked. In others, not so much. Maybe it's because I didn't follow the protocol 100%. Or maybe it was good ol' placebo effect at it again. And maybe it just doesn't plain work!