The cure for the common cold remains elusive, however that doesn't stop the list of ‘cures' from growing longer each winter. To date, this list has included tea with lemon and honey, garlic, chicken soup, megadoses of vitamin C, echinacea, and in the last few years zinc.

The first suggestion that zinc might have a role to play in colds was in 1984, when George Eby persuaded researchers at the University of Texas to test his idea that zinc gluconate lozenges shortened the duration of his 3-year-old daughter's colds.

It wasn't until 1996 when a study from Cleveland USA received wide spread attention. Studying 100 workers identified with colds, the researchers allocated half the group a lozenge containing zinc gluconate and the other half to a lozenge without. All were instructed to suck these lozenges every 2 hours for as long as they had symptoms. The researchers found that the zinc shortened the length of the cold by about 3 days. They theorised that extra zinc may work by stopping the cold rhinovirus from replicating.

Unfortunately since 1996, few studies have been able to reproduce this result. In 2008, a review of all trials concluded that positive evidence for zinc is still lacking. So, zinc's role remains uncertain and while some swear by their zinc lozenges, others find they suffer its annoying side effects - nausea, upset tummy and a bad taste in their mouth. You decide if it's worth it!

Don't overdo the zinc. Sucking too many lozenges or popping mega-dose zinc tablets can be harmful. The Safe Upper Dose of zinc is set at 40 mg a day. Exceeding this amount for an extended period of time can actually decrease immunity and trigger low copper levels.

The bottom line

Zinc may help you fight off the common cold, but if you're going to load up, do it for only 3 to 4 days and be wary of how much zinc you're ingesting!

Written by guest contributor, dietitian-nutritionist Catherine Saxelby, and reproduced here with permission from www.foodwatch.com.au.