It’s cold season and products that claim to prevent or significantly shorten colds are flying off the drugstore shelves.
As I emphasized in an earlier post, frequent hand washing is your best strategy to avoid a cold altogether.
Still, the advertisements for such products are both pervasive and persuasive But are they worth buying?
Vitamin C (1000mg) is the major ingredient of Airborne and Emergen-C. Both are made into fizzy drinks. Airborne also claims to have a “proprietary blend” of minerals and herbs, but it’s really about the vitamin C. The Food and Drug Administration (FDA) will not allow either to claim that they prevent colds; they can only state that they “boost” the immune system. The Emergen-C package actually has the following generic disclaimer:
This product is not intended to diagnose, treat, cure or prevent any disease. [my emphasis]
Um, why should we buy it, then?
Related post: The Quack Miranda Warning
Airborne recommends up to 3000mg per day; Emergen-C advises no more than 4000mg per day.
The recommended daily allowance for vitamin C is about 80mg/day. An 8-ounce glass of orange juice has 97mg.
Doses larger than 2000mg/day can lead to kidney stones, heartburn, nausea and diarrhea.
Despite over 60 years of clinical studies, there is no definitive proof that large doses of vitamin C can either prevent or lessen the duration of a common cold. In a 2010 review of the available research, the Cochrane Reviews concluded that
the failure of vitamin C supplementation to reduce the incidence of colds in the general population indicates that routine prophylaxis is not justified.
Zinc is the main ingredient in Cold-Eeze and Zicam lozenges. Because of positive results in a clinical trial by the Cleveland Clinic Foundation in 1996, both are allowed to claim, respectively, that they “reduce the duration of the common cold” and “get rid of your cold faster.”
How much faster? Half a day.
And to be effective, it must be taken within the first 24-48 hours of a cold, often before the symptoms are really noticeable.
Side effects include nausea and a metallic taste in your mouth.
In 2011, the Cochrane Reviews stated
it is difficult to make firm recommendations about the dose, formulation and duration that should be used.
Not exactly a glowing endorsement.
Bottom line: The facts behind these cold products, to me, do not support their questionable benefits over their cost and possible side effects. I would not spend money on any of them.
Eat a balanced diet throughout the year to keep your immune system healthy, and wash your hands!