When Nick Rous feels a cold coming on, he starts taking vitamin C and lots of garlic. When people around him come down with the flu, he reaches for echinacea and a homeopathic remedy, Oscillococcinum.
As a last resort, Rous, 30, says he turns to Tylenol and the nasal spray Afrin. "But I try to avoid that stuff as much as possible," says the saxophone player, who lives in San Francisco. "They just treat symptoms, but I feel like it's more productive to do things that boost your immune system and your strength."
Like Rous, many Americans are putting their faith in old standbys, such as vitamin C and zinc, and in relative newcomers.
Homeopathic remedies such as Oscillococcinum and combination products such as Airborne are apparently especially appealing.
In 2006, sales of homeopathic immune boosters grew 13%, according to data collected by the Nutrition Business Journal; Airborne's sales jumped nearly 50%, according to company figures. Although sales of formerly popular alternatives such as zinc and echinacea are lagging somewhat (sales dropped more than 6% and 16%, respectively, in 2006, according to the Nutrition Business Journal), they're still among the top sellers for cold and flu - and both, along with vitamin C, are common ingredients in many patented blends.
"People will go out and spend a whole lot of money on these different products, and unfortunately there's not that much that's been shown to be effective," said Dr. Ian Paul, a pediatrician at Penn State College of Medicine who has studied alternative remedies for coughs in particular (his research has so far shown that honey works better than cough syrup for kids).
In the absence of a cure for the common cold or flu, what most people are seeking is a little relief.
With alternative remedies, as with over-the-counter remedies, said Paul, that relief often comes from the belief that the treatment is working. "There's such a large placebo effect with a lot of these things," he said.
Andrew Shao, vice president of scientific and regulatory affairs for the Council for Responsible Nutrition, a trade association, agreed. "To say that things like vitamin C and zinc don't work wouldn't be totally accurate, because clearly for some people they do."
The research may be equivocal, Shao added, "but you hear people all the time saying, 'Well, I swear by it, it works for me.' "
There are, of course, better ways to treat or prevent a cold or the flu. A healthy diet with plenty of fruits and vegetables helps keep the immune system strong. Getting enough rest is critical for prevention and recovery. Exercise has been shown to reduce cold and flu infections, and so, of course, has frequent hand-washing.
And nothing is more effective at preventing the flu, Paul pointed out, than getting the flu vaccine.
Elderberries may make delicious, if uncommon, jams and pies -- but the jury's still out on whether they can cure the flu.
The number of proprietary elderberry products on the market has slowly grown in recent years, particularly in Europe. The berries contain high levels of vitamin C and flavonoids, plant pigment compounds that have shown antimicrobial activity in the lab. In the 1990s, Israeli researchers produced findings suggesting that the plant fought germs in humans too.
In one study, published in the Journal of Alternative and Complementary Medicine in 1995, people living in an Israeli commune during a flu outbreak in 1993 were given either four tablespoons of a proprietary elderberry extract, Sambucol, or the same amount of a placebo syrup daily for three days. Both groups came down with the flu -- but those who took the elderberry product recovered within two days, while the others recovered in six.
In 1999, the researchers tested the product during a flu outbreak in Norway. This time, the elderberry-treated group recovered in half the time it took the placebo group to recover: three to four days compared with seven to eight. The results were published in the Journal of International Medical Research in 2004.
In the U.S., Sambucol is sold in stores by supplement maker Nature's Way. A number of copycat elderberry products are appearing on shelves, claiming that elderberry coats flu viruses to stop them from infecting cells. But there's no evidence to back this up, and only Sambucol's patented formula has been put to the test.
Though Sambucol touts itself as an immune booster (the company's promotional materials suggest taking it daily), it's only been studied in outbreaks, and there's no evidence that it can prevent flu infection.
If cold symptoms alone don't make one's head spin, the sheer number of zinc options on the market -- lozenges, swabs, sprays and tablets containing various salts of the mineral -- surely will.
The buzz over zinc began in 1984, when researchers in Austin, Texas, published findings in the journal Antimicrobial Agents and Chemotherapy that showed sucking on 23-milligram zinc gluconate lozenges every two hours while awake helped volunteers infected with colds fully recover in one week -- while less than half of those who took placebo lozenges were back to normal in the same amount of time.
And then the conflicting evidence started to roll in. Dartmouth researchers showed, in the Journal of International Medical Research, that zinc gluconate shortened colds by nearly five days, but a study of 250 schoolchildren published in the Journal of the American Medical Assn. found that the lozenges did nothing.
The makers of Cold-Eeze, the popular zinc lozenges, chose to take their cues from researchers at Dartmouth and the Cleveland Clinic: Cold-Eeze contains 13.3 milligrams of zinc gluconate.
Though there's some indication that zinc lozenges can help if sucked every two waking hours, the reality is that that's a pretty tough regimen to follow, said Dr. Robert Bonakdar of the Scripps Center for Integrative Medicine in La Jolla. And zinc's bitter taste and tendency to irritate the mouth compound the problem.
"It's pretty nasty stuff, and it can give people gastrointestinal upset and nausea," Bonakdar said. One way around that series of hurdles is to put liquid or gel zinc directly in the nose. But there are fewer studies of intranasal zinc gluconate -- the active ingredient in Zicam Cold Remedy Nasal Gel and Swabs -- than those on lozenges. Some studies have found that when sprayed in the nose four times daily, intranasal zinc can clear up colds two to six days faster than placebos. But just as many studies showed the products do nothing.
Zicam in particular has been hobbled by legal troubles. In 2006, Matrixx Initiatives Inc., the company that makes Zicam products, paid $12 million to more than 300 consumers who had charged that the product damaged their sense of smell. The company denied wrongdoing, but redesigned the sprayer to address consumer complaints.
U.S. consumers have been abandoning echinacea in recent years. Sales of products derived from the herb fell more than 16% in 2006, according to the Nutrition Business Journal. But the science suggests that echinacea -- in the right form -- may be one of the more promising alternative cold remedies on the market.
Last summer, an analysis in the journal Lancet Infectious Disease showed that in well-designed studies, Echinacea purpurea shortened colds by an average of 1.4 days and reduced the odds of getting a cold by 58%. (Most studies administered around 900 milligrams or 8 to10 milliliters.)
The same report looked independently at five rigorously designed studies on Echinaguard and Echinacin, two proprietary blends of Echinacea purpurea juice, and found that they reduced the risk of getting a cold by 56%.
Dr. Robert Bonakdar, a physician with the Scripps Center for Integrative Medicine in La Jolla, pointed out that taking the right echinacea species is critical. A Cochrane review concluded that only Echinacea purpurea products showed any promise in treating colds, and only when they contained the aboveground parts of the plant -- not the root. Unfortunately, other formulations abound. Echinacea products can contain the roots, leaves or flowers of any of three species of the plant (purpurea, pallida or angustifolia), in dried, powdered or extracted form.
They may not even contain the plant. Researchers at University of Colorado Health Sciences Center published a paper in the Archives of Internal Medicine in 2003 showing that 10% of the echinacea products on store shelves in Denver contained no measurable echinacea at all.
The Cochrane reviewers stressed that echinacea showed promise only when taken early in a cold. Bonakdar concurred. "With any product, if you're not using it consistently, it's not going to have a benefit," he said.
Homeopathic remedies, such as oscillococcinum, contain extremely dilute amounts of natural substances that, in large doses, cause the same symptoms in need of a cure. In the case of "oscillo," as this unfortunately named French remedy is sometimes called, the natural substance is anas barbariae: extract of wild duck heart and liver.
Large doses of duck heart and liver don't necessarily cause sniffles, muscle aches and fatigue. But according to the homeopathic tenet maintaining that "like cures like," anas barbariae should cure flu, since waterfowl are a natural source of the flu virus.
Oscillo and similar remedies are popular in Europe; in the U.S., oscillo in particular has made its way from health food stores to mainstream drugstores during the last few years. A handful of studies has produced results indicating that the remedy can speed up recovery from the flu, but few of these studies were conducted with much rigor, according to researchers who reviewed them for the Cochrane Collaboration, an international consortium that promotes evidence-based medicine.
The reviewers concluded that there was no evidence to suggest that taking homeopathic remedies in general could prevent colds or the flu. Looking at the evidence on oscillo in particular, they concluded that it seemed to shorten the duration of flu slightly: by about six hours.
Reviewer Andrew Vickers, associate attending research methodologist at Memorial Sloan-Kettering Cancer Center in New York, says he is cautious about putting too much stake in this rather slim body of evidence.
"You can do a scientific experiment and it can give the wrong results for a variety of reasons, and one would be just bad luck," Vickers said.
Last year, Health Canada, the Canadian equivalent of the Food and Drug Administration, granted COLD-fX license to make a specific scientific claim -- something the patented American ginseng extract can't do in the U.S. The claim: Two 200-milligram doses of COLD-fX per day "helps reduce the frequency, severity and duration of cold and flu symptoms by boosting the immune system."
The Canadian agency's decision was based on positive findings from a series of well-designed studies. In one, published in the Journal of Alternative and Complementary Medicine in 2006, senior citizens who took COLD-fX for four months were 30% less likely to come down with respiratory symptoms in months three and four than seniors who took a placebo. A 2005 study of adults who took American ginseng or a placebo for four months found that those on the herb had 37% fewer colds; the results were published in the Canadian Medical Assn. Journal. Another large study of seniors, published in the Journal of the American Geriatric Society in 2004, found that the herb resulted in an 89% reduced risk of respiratory symptoms when taken for 12 weeks.
The herb hasn't been tested in children, and its ability to treat symptoms has yet to be tested.
Americans spend more money on vitamin C, roughly $330 million a year, than on any other purportedly immune-boosting supplement, according to the Nutrition Business Journal. Perhaps because it's been around so long.
"People take vitamin C during cold and flu season because since the 1950s, that's pretty much what we've all been told to do," said Daniel Fabricant, vice president of scientific and regulatory affairs for the Natural Products Assn., a Washington, D.C.-based trade association. "It's just in our subconscious mind-set."
But for just as long, scientists have been going back and forth on whether the vitamin is effective at preventing or treating the common cold.
Vitamin C was first isolated in the 1930s, and studies investigating its potential to prevent colds got underway in the 1940s. In 1970, two-time Nobel Prize-winning chemist Linus Pauling touted the powers of C in his best-selling book, "Vitamin C and the Common Cold." He was particularly inspired by a 1961 study at a ski school in the Alps. Kids in the study who took one gram of vitamin C per day (the U.S. Food and Drug Administration's daily reference value is 60 milligrams a day) had 45% fewer colds than their untreated classmates. They also recovered from colds in two-thirds the time it took their peers to get better.
Pauling's book and subsequent papers on the topic encouraged numerous researchers to investigate the alleged wonder vitamin in large-scale clinical studies of their own. Soon, conflicting evidence began to emerge. Some studies found the vitamin reduced the frequency of colds, some found it reduced the duration of colds, but still others found that it had no effect at all.
Last summer, the Cochrane Collaboration, a nonprofit organization that reviews the science on health topics, reviewed more than 50 well-designed, published studies on vitamin C and the common cold. The researchers found that taking at least 200 milligrams of C on a daily basis doesn't reduce the odds of getting a cold -- but it does speed recovery time by about 8% in adults. In children, it hastens recovery by 13.6%.
The reviewers found another interesting effect. While vitamin C doesn't keep colds at bay in most cases, it cuts the risk of colds in half in people under great physical stress: marathoners, skiers and soldiers training under arctic conditions.
Some evidence also suggests that taking a very large dose of C -- up to 8 grams -- at the onset of a cold could shorten the duration of infection or lessen symptoms, but the Cochrane reviewers concluded that more research was needed to confirm this effect.
For those who aren't winter marathoners or Olympic athletes, vitamin C probably offers little in the way of cold prevention, said Penn State's Dr. Ian Paul. "But is it harmful? Probably not," he added.
High-dose vitamin C does have a slight downside: Three to 5 grams at a time can cause gastrointestinal effects, including diarrhea.
Catchy packaging and celebrity endorsements have done much to make Airborne a hot seller among consumers eager to keep colds and flu at bay. The product, famously created by a schoolteacher who was tired of catching germs from her students, racked up more than $100 million in sales in 2006, after just a few years on the market.
Though individual consumers swear by the product and write to the company with testimonials of their satisfaction, hard evidence of the dissolvable tablets' efficacy is nonexistent.
The ability of Airborne's unique combination of 17 herbs, vitamins and minerals to cure or prevent colds or the flu hasn't been independently studied. The company cites the results of a small clinical trial on its website, but the results haven't been published or made publicly available.
The product contains popular remedies, including zinc, vitamin C and echinacea, which are likely of limited use in preventing colds or the flu. It also includes herbs such as lonicera and forsythia, which are far less studied for colds and flu. And three Airborne tablets -- the recommended daily dose -- provide more than the safe daily limit of vitamin A. A one-time overdose of vitamin A can cause headaches and nausea; over time, too much of the vitamin can cause bone weakness and dry, cracked skin.
OTHER 'IMMUNE BOOSTERS'
Countless immune boosters fly off the shelves year-round, particularly in cold and flu season. But even some of the most popular immune supplements haven't been tested against cold and flu in well-designed clinical trials.
No clinical trials, for example, have been conducted on goldenseal, a purported immune-booster sometimes used to fend off the common cold -- and there's evidence the herb may interfere with blood pressure drugs, decrease the activity of anticoagulants and hamper absorption of vitamin B. Goji, sometimes known as lycium, is a popular immune booster based on evidence from lab and animal studies, and some human research in China -- but no clinical trials have examined its ability to keep flu or colds at bay. The same is true for supplements derived from the tropical fruits noni and mangosteen.
A few herbs popular for other indications have recently shown preliminary promise for colds and flu. Green tea has been the focus of countless cancer and heart disease studies in recent years; just last fall, colds and flu were added to the list. A November 2007 article in the Journal of the American College of Nutrition reported that adults who took a green tea capsule twice a day for three months had 23% fewer colds and cases of the flu than people who took a placebo.
Andrographis paniculata, a fever remedy in traditional Chinese medicine, has been shown to kill microorganisms in lab studies. Combined with Siberian ginseng in a formula called Kan Jang, the herb reduced cold and flu symptoms in clinical trials conducted in Russia and Europe. In several large studies, it shortened flu recovery time slightly and reduced nasal secretion, congestion and coughs better than placebo. The downside: Kan Jang can cause headaches and fatigue in people not already suffering those symptoms because of the flu, and some people may be allergic to it.