The ABC believes that certain herbs can help healthy adults protect themselves against flu, diminish flu symptoms, and/or shorten flu intensity and duration, especially when taken at the first sign of flu symptoms.
According to Mark Blumenthal, ABC founder and executive director, there are a handful of herbs with proven safety that can help improve the body's immune functions. In this group he include echinacea, elderberry and the Chinese herb andrographis.
However, as Blumenthal notes, there is not total agreement in the scientific world as to the effectiveness of echinacea.
One recent Canadian clinical trial showed that the herbal extract lowered respiratory tract symptoms in people with colds.
Calgary-based Factors R & D Technologies in collaboration with researchers at the universities of Alberta, British Columbia and Dalhousie in Nova Scotia, as well as the Heinrich-Hein University in Düsseldorf, Germany and the Karl-Franzens University in Graz, Austria used an echinacea extract phytopharmaceutical to produce Echinilin, which they used in the tests.
"When clinical trial participants were given Echinilin, we saw an immediate and sustained increase in natural killer cells which target virus infected cells and destroys them," said Dr. Richard Barton, co-director of the human clinical studies. "This indicates that their immune system had been stimulated to target and destroy the viruses. The end result was an immediate and marked reduction in both severity of symptoms and duration of the infection."
Other researchers, though, are still undecided about the ability echinacea to reduce symptoms of the common cold and help patients recover faster.
A study published in June in the Archives of Internal Medicine (164:1237-1241), for example, showed that the herbal remedy had no effect on severity of symptoms and the time taken to recover from a cold compared to those given placebo.
The findings were based on a trial of 120 adults, who took 300 milligrams of an echinacea juice preparation daily at the first sign of a cold, and supported the results of a study in children last year.
This trial, published in the Journal of the American Medical Association, found that echinacea did not reduce the severity or duration of infections although it did appear to cut the number of respiratory tract infections in the children.
In a Norwegian study, published last year, scientists were able to demonstrate that patients receiving elderberry extract Sambucol recovered from the flu four days earlier than patients in the control group.
The study, which appeared in The Journal of International Medical Research, showed that on average, flu patients given Sambucol recovered in 3.1 days compared to 7.1 days for those given placebo.
The remedy, manufactured from Sambucus nigra L. by Israel-based Razei Bar Industries, is currently available in the US, Canada, United Kingdom, Holland, Belgium, Norway, Denmark, Israel, South Korea, Singapore and New Zealand.
A previous study published by The Journal of Alternative and Complementary Medicine had found that nearly 90 per cent of flu patients given Sambucol were completely free of symptoms within two to three days, as compared to at least six days with placebo.
Black elderberry has not, however, been tested as a flu preventative, nor is it intended as a substitute for flu vaccine.
"Some of the best things about elderberry are its mildness, its safety, and its great taste," said Blumenthal, adding that this makes it a good remedy for children too.
The ABC plans soon to publish a monograph on elderberry based on the scientific literature pertaining to this herb and will include the clinical and laboratory research documenting the beneficial immune-stimulating properties of elderberry preparations.
The third herbal that Blumenthal sees as having pronounced benefits for the immune system is andrographis.
A recent published review of 11 clinical trials shows that andrographis is safe and effective in treating upper respiratory tract infections associated with colds and flus, said the ABC.
"Unfortunately, despite its good record of being scientifically documented for its safety and benefits, it has not yet become popular in the US, although it is available from a few manufacturers," said Blumenthal.