Concern over use of zinc as common cold cure

IT’S BACK to school time

IT’S BACK to school time. Along with carrying all their books, some pupils will be bringing home the bugs that are making their way around the school. The search for cold remedies will soon be upon us.

Zinc supplements have been popular for colds, but they took a turn for the worse this summer. In June, the US Food and Drug Administration (FDA) warned Americans not to use Zicam intranasal products. These gels and swabs deliver homeopathic zinc directly into the nose and claim to reduce the duration of a cold and relieve many of the symptoms.

The FDA reported that it had received more than 130 complaints from people claiming they lost their sense of smell after using these products. It also demanded that the manufacturer, Matrixx, forward the 800 additional complaints it had received. By law, drug manufacturers are required to send such complaints to the FDA, but Matrixx had failed to do so.

The manufacturer insists its zinc intranasal products are not the cause of damage to people’s sense of smell. However, Matrixx paid $12 million (€8.25 million) in 2006 to settle 340 lawsuits on this same issue.

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The FDA noted it had no data supporting the effectiveness of these products in treating the common cold and requested that Matrixx withdraw the products from the market. Matrixx refused to do so, which prompted the public warning by the FDA.

While zinc for the common cold has been getting bad press, other news has been very encouraging. During the 1990s, researchers in developing countries noticed that children given zinc supplements suffered dramatically less from diarrhoea.

The results were initially treated with scepticism, especially as no one could explain how zinc could help these children. Questions remain about how it works, but several controlled studies have since supported the use of zinc in treating acute and persistent diarrhoea in children.

The potential impact of zinc was recognised in the 2008 Copenhagen Consensus Statement, in which internationally recognised economists, many of them Nobel Laureates, ranked the provision of zinc and vitamin A supplements for children as the most cost-effective way to promote human welfare.

Diarrhoea has a devastating impact in developing countries, though it rarely draws much public attention. It is the second-leading cause of death among children, killing about two million under-fives every year.

The long-term personal, social and economic costs are staggering. The causes of diarrhoea are complex, including unclean water, malnutrition and numerous infectious agents.

Solutions are not simple. Since the 1970s, the main treatment for diarrhoea has been oral rehydration therapy (ORT). Inexpensive sachets of sugar and salt are mixed with clean water to prevent dehydration.

In 2004, WHO and Unicef jointly recommended the use of ORT along with zinc to treat diarrhoea in children.

Countries which have implemented these simple treatments report many saved lives and the reduced use of unnecessary antibiotics, all at low cost. Yet few countries provide zinc for those who need it, and millions of children continue to die unnecessarily.

Concerns may be raised that the problems found with zinc nasal products might occur in children given zinc for diarrhoea. However, the cold remedies are delivered directly into the nose, while the diarrhoea treatment is given as tablets or syrup.

Loss of smell has only been reported with intranasal products. Oral zinc has a bad taste and can cause vomiting, but these are viewed as risks worth taking, given the deadly consequences of leaving diarrhoea untreated.

Zinc highlights the injustices of global health. In wealthy countries, we can easily afford zinc supplements that are of questionable benefit for a nuisance like the common cold. In developing countries, children are dying because they lack clean water and the same supplements.

Addressing global health problems requires multifaceted solutions. But it might help us to put up with those irritating cold symptoms if we knew we were doing something to help those in critical need.

Various aid agencies need help in making zinc available, which could contribute greatly to achieving the Fourth UN Millennium Development Goal: reducing child mortality by two-thirds before 2015.

  • Dónal OMathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a senior lecturer in the School of Nursing, Dublin City University