A desk study which has sifted through the available scientific evidence suggests taking zinc within a day of the onset of cold symptoms speeds recovery.
Take it when you think that you may be in the presence of cold sufferers, and it may also help fend off colds, the review authors think, after looking at research papers that included data from 15 trials involving in all, 1,360 people.
However, zinc is a heavy metal which normally isn’t permitted above a few parts-per-million in drinking water, by the World Health Organisation, and cannot be used for long periods due to its toxicity effects if it builds up in the body.
Just like any poison it can cause nausea, vomiting, abdominal pain and diarrhoea.
The authors of the Cochrane Systematic Review, point out that within the trial reports studied the efficacy of the treatment varies widely, and was not very consistent. The best that could be said was that overall the evidence points to effectiveness in zinc treatment. However, more work is needed to determine the exact dosing required, and the best form whether these be syrup, tablets or lozenges etc.
Individual studies continue to highly variable on the benefits of zinc as a cold-fighter. This is not new, as in 1999, the Cochrane review found it hard to demonstrate that zinc helps the reduction of common cold misery. Studies of zinc, taken orally, report positive results, while one study of topical zinc reports negative results.
Zinc has been studied over the years for other benefits and there are a number. Studies indicate that children treated with supplemental zinc had an reduced, by about one fifth to one sixth, average stool frequency in acute and persistent diarrhoea, respectively, compared to those who didn’t receive the supplement (Lukacik et al., 2008). In addition, zinc supplements have been shown to possess a preventive and long-lasting effect, reducing the number of occurrences of diarrhoea for an additional two to three months. These studies also revealed that children receiving zinc show a decrease of the intensity of their diarrhoea attacks.
Oysters have the highest level of zinc of any food. Oysters contain more zinc per serving than any other food, but generally, meat (especially liver) and fish, especially shellfish, codfish and bluefish, are an optimal source of zinc.
Beans, nuts, and some dairy products also contain higher than average zinc.
For the pharmaceutical industry the discovery that zinc is an effective treatment for the common cold will generate little enthusiasm, and no significant potential profit yields, given that it is hard if not impossible to patent a drug as basic and simple as a metal. However, in terms of the benefit to national economies and in reduced suffering, a common cold cure, even if only partial, is substantial in human terms.