The herb echinacea showed little benefit in treating the common cold, according a study.
Echinacea sales rose 7 percent to $132 million in the U.S. last year, according to the Boulder, Colorado-based Nutrition Business Journal. The herb was used by American Indians for centuries to treat coughs, infections and snakebites. Now it is widely taken by patients to fight colds, researchers said.
Scientists have disagreed for years over whether echinacea can prevent infection or speed recovery. The Wisconsin research found a benefit so small that is may have been due to chance, said Bruce Barrett, the lead author.
The treatment “doesn’t decrease the severity of colds by a large amount,” said Barrett, an associate professor of family medicine at the University of Wisconsin School of Medicine & Public Health, in Madison, in a telephone interview on Dec. 15. The gains “were too small to be statistically significant.”
Research patients in Wisconsin took tablets with the equivalent of 10.2 grams of dried echinacea root in the first 24 hours of treatment, and half that much in each of the next four days. Those participants had a 10 percent drop in the severity of colds compared with people on a placebo, authors led by a University of Wisconsin doctor said today.
Colds lasted about half a day less when people took echinacea, the researchers said today in the Annals of Internal Medicine. The herb is a perennial purple coneflower resembling a black-eyed Susan.
The study covered 719 patients ages 12 to 80 who had new colds. The participants were assigned to groups that received echinacea, or else a placebo or no pills at all. People given the placebo, and half of those taking echinacea, weren’t told what they were taking.
Patients who didn’t know they were on echinacea had colds that lasted about 6.34 days on average compared with 6.87 for people on placebo, the researchers said.
While the researchers said echinacea was associated with an estimated 10 percent lessening in the severity of colds, they said no more than a quarter of people “would judge this level of benefit worthwhile, given the cost, inconvenience and possible side effects,” such as stomach upset, nausea and diarrhea.
“Any underlying benefit of echinacea is not large and was not demonstrated by our results,” the authors wrote.
The study was funded primarily by the National Center for Complementary and Alternative Medicine, part of the U.S. National Institutes of Health, based in Bethesda, Maryland.
The agency also backed a study that appeared in the New England Journal of Medicine in July 2005. In that report, authors led by Ronald B. Turner, a professor of pediatrics at the University of Virginia in Charlottesville, said three different extracts from echinacea roots had failed to prevent infection or reduce its severity.
Not all studies have flunked the herb as a cold remedy.
In the July 2007 report in Lancet Infectious Diseases, researchers reviewed 14 studies and concluded that echinacea cuts the odds of developing a cold by 58 percent and the duration of the illness by 1.4 days.
‘Not All Alike’
“Echinacea products are not all alike,” said Mark Blumenthal, founder and executive director of the American Botanical Council, a nonprofit organization based in Austin, Texas, in a telephone interview on Dec. 15. “The challenge is determining which ones have the most benefit or any benefit.”
The studies showing the most efficacy for echinacea in fighting colds looked at formulations made from the root and leaves of Echinacea purpurea, one of three different species, he said. The tablets used in the new study contained roots of the purpurea species and another, according to the report.
Each year, the economic cost of the common cold is about $40 billion in the U.S., reflecting 20 million doctor visits and 40 million work and school days lost, the researchers said, citing a 2003 estimate by scientists at the University of Michigan in Ann Arbor.
The Michigan researchers conducted a telephone survey of more than 4,000 households to learn the prevalence of colds and treatment patterns, and extrapolated the results to the U.S. as a whole. Their report appeared in the Archives of Internal Medicine in February 2003.