American Ginseng May Prevent Colds

American Ginseng May Prevent Colds

EDMONTON, Alberta--Extracts ofthe root of North American ginseng (Panax quinquefolium) have been foundto have the potential to modulate both natural and acquired immune responses andprevent upper respiratory infections, according to a study published in the CanadianMedical Association Journal (173,9:1043-1048, 2005).

Researchers conducted a randomized, double blind, placebo-controlled study atthe onset of the influenza season. A total of 323 subjects 18 to 65 years of agewith a history of at least two colds in the previous year were recruited fromthe general population in Edmonton, Alberta. The participants were instructed totake two capsules per day of either a North American ginseng extract containingpoly-furanosyl-pyranosyl-saccharides or a placebo for a period of four months.The primary outcome measure was the number of verified colds. Secondaryvariables measured included symptom severity, total number of days of symptomsand duration of all colds. Cold symptoms were scored by subjects using afour-point scale.

Subjects who did not start treatment were excluded from the analysis (23 inthe ginseng group and 21 in the placebo group), leaving 130 in the ginseng groupand 149 in the placebo group. The mean number of colds per person was lower inthe ginseng group than in the placebo group. The proportion of subjects with twoor more verified colds during the four-month period was significantly lower inthe ginseng group than in the placebo group, as were the total symptom scoredifference and the total number of days cold symptoms were reported for allcolds.

Researchers concluded ingestion of a polysacchariderich extract of theroots of North American ginseng in a moderate dose over four months could reduceboth incidence and severity of colds.