Airborne takes off, but why?

CONSUMER REPORTS February 2006

"There's a natural way to boost your immune system to fight the germs and viruses that cause colds," says a press release for Airborne, an "effervescent health formula" whose ingredients include herbal extracts, vitamins, electrolytes, amino acids, and antioxidants. A schoolteacher consulted with nutrition experts and herbalists to come up with its formula.

Airborne had sales of more than $65 million for the 12 months ending in October 2005. Even Oprah has said she keeps it on hand. Although Airborne claims "there's nothing else like it," it has spawned two imitators, AirShield, sold at CVS, and Wal-borne, sold at Walgreen's.

Each tablet of all three products contains 1,000 milligrams of vitamin C. For Airborne and Wal-borne, the recommended adult dose is one tablet every three hours "as necessary." A spokesman for Airborne said that as of January 2006, the label of the new pink-grapefruit flavor will list a maximum dosage of three tablets per day for up to 21 days. (Labels for other flavors are scheduled to change in fall 2006.) AirShield suggests up to four tablets a day.

But dosages that high could be cause for concern. Taking more than 2,000 mg of vitamin C per day can greatly increase the risk of diarrhea and gastrointestinal upset, according to the National Academy of Sciences' Institute of Medicine, which advises the government about recommended levels of nutrients.

Eric Taylor, M.D., a nephrologist at Boston's Brigham and Women's Hospital, says that he would hesitate to recommend any vitamin C supplement for some people who have had the most common type of kidney stones because of an increased risk of more stones.

With regard to Airborne's effectiveness, a company representative cited an unpublished clinical trial as evidence that the product fights colds. But the study was small, not statistically validated or peer reviewed, and sponsored by the manufacturer. Whether Airborne and its imitators work or not, think twice about taking the top dosage. Here's a reason to think three times: 10 tablets cost $5 to $7.