To Zinc, or not to Zinc?
Zinc is an essential trace element in the human body. It ranks number two right behind iron, and it's necessary for normal childhood growth, gene expression, and wound healing. Chances are that if you take a multivitamin, it has zinc in it. Zinc is a necessary element during pregnancy and is necessary for normal taste and smell sensation. Zinc helps to keep the T-cell arm of cellular immunity intact and helps protect against macular degeneration in the eyes. It even helps support cell division in everyday life within the body.
Before you start reaching for the zinc supplements keep in mind a normal diet generally gives you all the zinc you need. It's present in beef patties, cheese, crab and oysters, fish such as sole and flounder, chicken, beans and nuts. A lot of foods are enriched with zinc as well, such as breakfast cereal and oatmeal. But sometimes a little more zinc may be helpful, as one of zinc's major uses is advocated in preventing or shortening the duration of the common cold virus.
Zinc appears to have effects on viruses in the body- it is said to lessen symptoms of the common cold and, if taken early enough, shorten the duration of sickness. Studies are still controversial, but researchers from McMaster University and the Hospital for Sick Children published a study in the Canadian Medical Journal that certainly supports this finding. They found that zinc significantly shortened the duration of colds when compared to placebos, and that the duration of the cold was shorter. The studies used data on over 2,100 people ages 1-65, so certainly age wasn't the only factor. Compared with placebo, zinc appeared to significantly improve cough, nasal discharge and muscle aches. Not every study confirmed this, but enough did to suggest it may be helpful.
So how much zinc do you need, when do you start it and how does it work? To answer the last question first, scientists are not quite sure. It is thought that zinc inhibits the cold (rhinovirus) binding and replication in the nasal passages. Its role in immune function is thought to boost the immune system response to exposure of the common cold virus. It is generally most effective when you take it early in the course of the illness, within the first couple of days. It is available orally in pills that provide milligrams of elemental zinc, but it is most conveniently used in the form of lozenges that are ingested and commercially available in most pharmacies.
What dosage is best and can you actually ingest too much zinc? The standard amount of zinc in commercially available lozenges is between 5mg and 13.3mg, with the latter being the most common. While daily ingestion of zinc is not recommended over 35mg, the amount is higher in treating illness or sickness. The maximum amount suggested is up to 80mg (6 lozenges) in a day for 3-7 days. Too much zinc can cause unpleasant gastrointestinal symptoms and can cause blood abnormalities, but not at these doses or limited durations.
Does zinc help? There is enough anecdotal and study evidence to suggest it actually is beneficial in shortening cold duration and lessening symptoms. And as a mother would say, in therapeutic doses, "It couldn't hurt…"
Authored by Dr. Bob Goldstone, M.D.
The information contained on this page is not intended to provide medical advice, which should be obtained directly from your physician.