Zinc supplements have been touted for many years as a prevention for colds and flus, and even as a means of reducing the duration of upper respiratory viruses. But research results have been very mixed – some studies showing zinc to be a potent anti-viral, while others showing it to have little to no effect.

Newer findings are shedding light on the subject and it appears that there are some variables that make a huge difference in the effectiveness of zinc in colds and other viruses.

First of all, as many zinc promoters have advised, it’s important to let the zinc tablets/lozenges dissolve in your mouth, rather than swallowing them whole or even chewed up. Zinc ions inhibit the ability of viruses to replicate, and the more dispersed the zinc is, the more virus particles it will come in contact with and inhibit.

But there’s a problem with letting zinc lozenges dissolve in your mouth – zinc compounds don’t taste very good. They naturally have a metallic taste that I’ve heard described as “sucking on pennies.”

So, to make them more palatable, many zinc supplement manufacturers add sugar and various flavorings to them. Herein lies what appears to be the biggest difference in the outcomes of the various studies over the years. Many of the added ingredients used for flavoring chemically bind to the zinc, making it significantly less available to bind to, and inhibit, viruses. In fact, in some formulations, the available zinc was found to be essentially zero, whereas 100% of the zinc was available in unflavored zinc acetate (which, along with zinc gluconate are the probably the best forms).

So, avoiding or at least minimizing the effects of a cold do come at the cost of some less-than delicious zinc lozenges, but most people will probably consider it a good trade-off.

Taken within a few hours of the first symptoms, zinc lozenges allowed to dissolve in the mouth can be very effective at preventing viruses from taking hold and prevent you from actually getting sick. But even with delayed intervention once a cold has set in, zinc can shorten the duration of symptoms by 2 to 3 days, which is about a 30 to 40% reduction in how long the usual cold lasts.

So, what about dosage? Well, using zinc as a prevention / remedy for a cold is different from taking it as a general dietary supplement. In general, the recommended long-term daily use dosage is 40 mg or less. But for short-term application for fighting colds and other viruses, the effective dosage found in studies was a total of 75 to 100 mg per day. Most lozenges are intended to be fully dissolved in the mouth with one taken every few hours.

In addition to dissolving them in the mouth rather than swallowing whole supplements being much more effective in inhibiting viruses, it’s also easier on the stomach. Even so, with the relatively high doses used for colds and flus, zinc can cause stomach upset. If this is a problem, having some food on the stomach prior to taking zinc is usually helpful.

Until next time…

George F. Best, D.C.