5: Zinc may lessen the severity of symptoms.
When you think that children get an estimated eight to 10 colds annually, and adults three, the number of sneezes and coughs you hear around you starts to make sense [source: Benkoff]. Well, what if those hacking coughs could become more subtle coughs that don't shake your ribcage so furiously? That's the claim behind the controversial theory that zinc-based cold remedies may lessen the severity of cold symptoms.
It is thought that zinc-based cold remedies, which come in cold lozenges, gels and nasal sprays, may work by actually stopping the cold virus in its tracks. If correct, that means zinc doesn't allow the virus to stick inside of our noses and throats and replicate [sources: Kim, Office of Dietary Supplements]. This would handicap the virus and provide some relief.
However, this theory is largely unproven. In fact, one review of all the research studies conducted on zinc and colds found that just four studies out of 14 that used placebos were conducted with scientific significance and following principles of research design. Of those four, just one outlined positive results [source: Physorg.com]. As such, the general consensus is that more research is needed.