Special Feature

In from the Cold

by David Schardt, March 2011

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Last December, in settling a complaint by the Federal Trade Commission, Dannon agreed to stop its “false and misleading” ads implying that people who drink DanActive probiotic beverage are less likely to catch a cold or the flu. (Never mind that a product that enhanced your immune system could make cold symptoms worse.)


But that probably won’t make a dent in the millions of dollars consumers will shell out this year on cold and flu remedies. Are they wasting their money? Here’s the evidence behind some popular products.


Claim: “Clinically proven to shorten colds by nearly one-half.”

What’s in it: 13.3 milligrams of zinc gluconate per lozenge.

Cost: $2.40 a day for the maximum dose.

The facts: Can Cold-Eeze really shorten the duration of colds? (The manufacturer can make that bold claim because Cold-Eeze is a “homeopathic” medicine—see “Wherefore Art Thou Homeo?”)

“In our studies, we saw about a one-day reduction in the duration of colds, but no change in the severity, when we induced colds in volunteers with nasal drops,” says the University of Virginia’s Ronald Turner. “But we didn’t see any effect in volunteers who caught colds on their own.”

Bottom line: In some studies, zinc gluconate lozenges shorten—by a day or two—the duration of colds. In other studies, they don’t.


Claim: “Clinically shown to help activate and guard your immune function.”

What’s in it: Fermented brewers yeast.

Cost: $20 a month.

The facts: Two studies have given EpiCor or a placebo to a total of 232 people for three months and waited to see who got sick.

In the more recent one, the EpiCor takers had 13 cases of cold or flu for every 15 cases in the placebo takers, but their illnesses were just as nasty and lasted just as long.1 In the other study, for every seven colds in the EpiCor group, there were eight colds in the placebo group. And the EpiCor takers were sick for an average of one day less.2

Bottom line: If larger trials confirm these modest results, taking EpiCor every day could mean one less cold roughly every three years.

1 J. Altern. Complement. Med. 16: 213, 2010.
2 Urol. Nurs. 28: 50, 2008.


Claim: “Can be recommended as part of a regimen for Winter Wellness,” says NatureMade. What’s in it: Purple coneflowers.

Cost: 30 to 40 cents a day.

The facts: Since 2000, U.S. and Canadian researchers have published nine studies that tested the purpurea strain of Echinacea against colds.

Three of the studies looked at whether taking Echinacea every day could prevent colds. It didn’t. The other six looked at whether taking Echinacea every day at the first hint of a cold could lessen its symptoms or shorten its duration. In four of them, Echinacea was no more helpful than a placebo. In the other two, Echinacea takers reported slightly milder symptoms than placebo takers.

“There are so many different products available that are not standardized,” says cold expert Ronald Turner. “It’s impossible for consumers to figure out which of them might possibly have a small benefit.”

Bottom line: Echinacea doesn’t prevent colds. In most studies, it also doesn’t lessen cold symptoms.


Claim: “Helps support your immune system.”

What’s in it: Nine vitamins and minerals, a trivial amount of two amino acids, and a blend of herbs.

Cost: $2.25 a day.

The facts: “There is no credible evidence that Airborne products, taken as directed, will reduce the severity or duration of colds, or provide any tangible benefit for people who are exposed to germs in crowded places.” That’s what the Federal Trade Commission charged in 2008 in announcing that Airborne’s manufacturer had agreed to stop making those claims and to provide up to $30 million in refunds to consumers who believed they were deceived by the company’s ads.

Airborne now contends that it can “help support your immune system.” There’s no credible evidence for that assertion either, but since it’s classified as a “structure or function” claim, the company needs no evidence. Pretty slick.

Bottom line: Despite hundreds of millions of dollars in sales, there is no evidence that Airborne works.


In 1971, a typical supermarket carried just under 8,000 items. In 2009, it was more than 48,000.

Claim: Provides “immune system support.”

What’s in it: Extract of elderberries. The “Original Formula” contains 3.8 grams of extract in a two-teaspoon serving. Sambucol USA wouldn’t disclose how much is in the “Cold & Flu Relief” formula (the homeopathic version).

Cost: $4.00 a day for “intensive use.”

The facts: Israeli researchers gave 15 adults and children who were coming down with the flu four tablespoons of Sambucol every day for three days, while 12 similar adults and children were given a placebo syrup. Symptoms cleared up three days faster in the Sambucol takers.1 And 60 Norwegian men and women coming down with the flu were given four tablespoons of Sambucol or a placebo every day for five days. Symptoms cleared about four days faster in the Sambucol takers.2

Both studies used Original Sambucol. There’s no evidence for the homeopathic formula.

Bottom line: Original Formula Sambucol helped people recover from the flu faster in two small studies, but larger trials are needed.

1 J. Altern. Complem. Med. 1: 361, 1995.
2 J. Intern. Med. Res. 32: 132, 2004.

Vitamin D

Claim: “The One Vitamin that Will Stop Flu in Its Tracks,” proclaims drmercola.com. What’s in it: Vitamin D.

Cost: About $1.50 a month for 1,000 IU a day.

The facts: Vitamin D increases the production of antimicrobial peptides (small protein-like natural antibiotics) in the body’s cells. And in two U.S. studies, people with higher vitamin D levels in their blood had a lower risk of upper respiratory infections. Does that mean that taking vitamin D can stop the flu (or a cold)?

Japanese researchers gave 334 children either 1,200 IU of vitamin D or a placebo every day from December through March. The vitamin D takers had six cases of the flu for every ten cases in the placebo takers.1

But three trials in adults—using 400 IU a day for six months, 800 IU a day for 11 to 25 months, or 2,000 IU a day for three months—all came up empty.2-4 In none of the studies did those taking vitamin D have fewer cases of the flu or other respiratory infections than similar people who were given a placebo.

Bottom line: The evidence that vitamin D can prevent colds or the flu is meager.

1 Am. J. Clin. Nutr. 91: 1255, 2010.
2 J. Infect. Dis. 202: 809, 2010. 3 Age and Ageing 36: 574, 2007. 4 Epidemiol. Infect. 137: 1396, 2009.

Wherefore Art Thou Homeo?

DayQuil. Cold-Eeze. Sambucol. All three claim to help you cope with colds and the flu. But each represents a different class of remedy, and the Food and Drug Administration regulates each in a very different way. That affects how much you can trust the products’ claims.

  • DayQuil is an over-thecounter (OTC) medication. OTC manufacturers have to convince the FDA that any claims they make are supported by solid scientific evidence before their products hit the market. Since no OTC drug has been proven to prevent or shorten colds or the flu, OTC remedies can only claim to relieve symptoms. —You can generally trust OTC claims.
  • Sambucol is a dietary supplement. (The FDA requires dietary supplements to say so on the label.) Dietary supplements can’t make claims about relieving colds or the flu without prior FDA approval, but they can make vague “structure or function” claims, like “helps support the immune system,” without having to prove that they’re true...or that they make any difference. —Be skeptical of dietary supplement claims.
  • Cold-Eeze is a homeopathic medicine. (The FDA requires homeopathic medicines to say so on the label.) Homeopathic remedies can claim to prevent or cure colds and the flu without having to show any proof to the FDA. Why?

    Traditional homeopathic drugs aren’t considered a safety hazard because they’re diluted repeatedly until there’s nothing left of their active ingredients. And in the past, few people used them. So, in 1938, Congress exempted them from strict regulation.

    But that no longer makes sense. Homeopathy has become a huge industry that sells its products by the millions to shoppers everywhere from Walmart to supermarkets to the Internet. And many (Cold-Eeze, for example) contain substantial amounts of active ingredients.

    “I seriously doubt if one-twentieth of the so-called homeopathic products sold in stores today have any basis in homeopathic principles,” says Southern Illinois University’s John Haller, an authority on the history of homeopathy. “That’s homeopathy’s dirty little secret.” —Be skeptical of homeopathic medicine claims.

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