Again and again. Megadosing vitamins, i.e., taking a much higher dosage of a vitamin than recommended, does not ward off colds, or help end them faster.¹ In fact, high doses of vitamins can damage you. Any significant change in your diet, including these woo-pills, should be checked against a qualified medicinal professional first.

Anywho, Airborne, a popular health supplement marketed as expediting the recovery from colds, or stopping them from starting, setted a huge deal with consumers because their product is basically a placebo in the context of its stated purpose. But make no mistake: because they settled, the company admits no wrongdoing:

"There's no credible evidence that what's in Airborne can prevent colds or protect you from a germy environment," said CSPI Senior nutritionist David Schardt. "Airborne is basically on overpriced, run-of-the-mill vitamin pill that's been cleverly, but deceptively, marketed."

You can claim a refund if you've bought Airborne in the past few years. This, in my opinion, let's Airborne off the hook lightly. However, the FDA's regulation of supplements is notoriously lack. What they got Airborne on, however, is misleading advertising:

"Airborne changed their advertising campaign when a plaintiff filed suit against the company in March 2006.That came after an ABC News report disclosed that the company's clinical trials were not conducted by doctors or scientists, but instead carried out by two laypeople."

Can you believe that? Two non-scientists? Scientific studies are very difficult to perform in an objective manner already, even for scientists. Bias can be introduced everywhere and it's incredibly easy to do so. Yet Airborne thought it proper to cite research done in a very questionable fashion. Their settlement is very forgiving for what they did.

One of my favorite quotes from Airborne's website however, is that Airborne, "boosts the immune system with seven herbal extracts and a proprietary blend of vitamins, electrolytes, amino acids and antioxidants." Okay, fine. Let's say it boosts the immune system. What does this mean? A typical response to pathogens in the body for the immune system is inflammation and it's an important step in keeping you well. For most people, that is, people without AIDS or another immunodeficiency disease, their immune system is working great. They're healthy! To "boost" a healthy immune system would be to increase its response to normal stimuli. This means to increase inflammation. If instead of marketing "boosting the immune system" with the equivalent phrase, "inducing chronic inflammation" you wouldn't sell much, and for good reason. I guess it's a good thing that these products don't do anything.

Sources:

1. Douglas RM, Hemilä H (2005). "Vitamin C for Preventing and Treating the Common Cold". PLoS Medicine 2 (6): e168. doi:10.1371/journal.pmed.0020168.