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It's MORNING EDITION from NPR News. I'm Steve Inskeep.
RENEE MONTAGNE, host:
And I'm Renee Montagne.
In Your Health today, a unique way to deal grief. First, popular ways of dealing with the common cold.
NPR's Allison Aubrey looks into supplements that claim to boost your immune system.
ALLISON AUBREY: Everybody knows that colds are caused by viruses, but when a nasty one spreads around the office or through the family, why do some people get sick and others don't? Some swear by a jolt of wheat grass in their smoothies or mega doses of Vitamin C.
Another top seller in drugstores is Airborne - a mix of herbs and vitamins that claims to boost the immune system. One shopper, Norie Nuzrat(ph), who was on her way into a health food store says, of course, she's heard of Airborne.
Ms. NORIE NUZRAT (Shopper): Actually, my fiancé takes it all the time and he says it works to prevent him from getting sick. That's why - he swears by it, actually.
AUBREY: He's not alone. Sales of Airborne have jumped from $2 million to more than $100 million in the last four years. But is there any evidence to show that Airborne tablets can actually prevent someone from catching a cold?
Dr. RONALD TURNER (University of Virginia, School of Medicine): No, no. I will have to say that they're unproven.
AUBREY: Ronald Turner is a physician who studies how people catch colds. He heads a clinical research at the University of Virginia's School of Medicine. He's not just skeptical of Airborne, but of all supplements that claim to boost the immune system.
Dr. TURNER: There's never been anything that's been definitively shown to either prevent or treat common-cold illnesses.
AUBREY: The makers of Airborne have conducted only one small research study. They found that four out of five people who took Airborne either recover completely or improved somewhat within five days. The results may sound promising, but Ronald Turner says people who do absolutely nothing to treat their colds also gets better just as quickly.
Dr. TURNER: Without any intervention of any kind.
AUBREY: The marketers of Airborne say they'd like to do more research. But for now, scientists say the only way to evaluate the product at all is to look at its main ingredients.
Airborne contains herbs such as Echinacea, which although very popular, has been shown by the best scientific studies not to work. It also contains mega doses of vitamins C. Most people get plenty of that in their diet.
Dr. TURNER: Having vitamin C is an important nutrient for the body, but to extrapolate because it's necessary for the body, that then taking a high dose of it somehow is protective or is more beneficial, that's where the fallacy comes in.
AUBREY: Then there's Zinc. Researchers have studied Zinc repeatedly with very mixed results.
Dr. TURNER: What you like to see when you do science is that as you do studies and you identify problems with the studies and you modify your design, and you repeat the studies and that sort of thing that - that eventually all the studies start to come out close to the same.
AUBREY: But in the case of Zinc, results has been all over the map.
Dr. TURNER: There have been studies that have shown very dramatic reductions in symptom duration, and then there are studies of very similar design that show no reduction in symptom duration.
AUBREY: So if all the evidence suggests there is no magic elixir that will keep you from getting a cold, is there anything besides washing your hands a lot that you can do to protect yourself?
Researcher Sheldon Cohen at Carnegie Mellon University studies the role of stress.
Mr. SHELDON COHEN (Researcher, Carnegie Mellon University): We know quite a bit about stress and susceptibility to infection. We've been doing research in that area for probably over 25 years.
AUBREY: In one study, Cohen and his collaborators interviewed 400 healthy adults, about how stressed out they are. They asked questions such as whether the demands, they say, exceeded their ability to cope; or how anxious, angry or depressed they'd felt a little last week.
Mr. COHEN: After we administered the questionnaires, we exposed the people in the study to one of five different viruses that cause the common cold.
AUBREY: Cohen's team then tracked the volunteers for six days and found those who had reported higher levels of stress were twice as likely to catch a cold as those who were less stressed out. This correlation has held up in two follow-up studies. Cohen says he's also looked at long-term stressors, such as marriage problems or the loss of a job.
Mr. COHEN: So the longer the stressor had lasted, the greater the probability that when we exposed them to a virus that they quickly develop a cold.
AUBREY: Taking stress out of our lives is not something that any of us can do on demand. Unresolved disputes don't disappear at will. So maybe it's no surprise that consumers are willing to buy into the possibility that things like Airborne, or Zinc tablets, or Echinacea can protect them.
Mark Orlandez(ph), who has stopped in to buy a smoothie, says he doesn't really believe in any of this stuff. Still if he's coming down with a cold, sometimes he reaches for it.
Mr. MARK ORLANDEZ: Maybe it's mental like that you're taking it and you feel like your immune system should be like stronger or maybe you get over stuff faster. It could be just purely mental.
AUBREY: One thing is for certain, whatever you do, you'll feel better soon. Wait a week the cold will go away.
Allison Aubrey, NPR News, Washington.
MONTAGNE: And you can find out whether kids who hate to wear coats are more likely to get colds at npr.org/YourHealth.
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