Ginseng effective in common cold, study suggests
Taking North American ginseng reduces the mean number of colds experienced per person over four months, as well as reducing the severity and duration of symptoms, according to researchers in Canada.
The researchers recruited 323 subjects in good general health, aged 18–65 years old, who had experienced at least two colds in the past year and had not received an influenza vaccination. Participants were given two capsules of North American ginseng extract (Panax quinquefolius) or placebo daily for four months. Number of colds and symptoms were evaluated by self-completed patient diaries and telephone contact with the investigators.
The mean number of colds per person was lower in the ginseng group than the placebo group (0.68 versus 0.93 colds; P=0.017). In addition, 10 per cent of participants in the ginseng group reported having more than one cold compared with 22.8 per cent in the placebo group. The total symptom scores and total number of days that colds were experienced were also lower in the ginseng group than the placebo group. The researchers estimate an absolute risk reduction of recurrent colds of 12.8 per cent with ginseng.
“[North American ginseng] therefore appears to be an attractive natural prophylactic treatment for upper respiratory tract infections. However, further studies are required to assess its efficacy and safety for children and immunocompromised populations,” the researchers conclude (Canadian Medical Association Journal 2005;173:1043).
The author of an accompanying commentary (ibid, p1051) highlights that the strict case definition used by the researchers limits their evaluation to only the most severe illnesses that occur during the influenza season. “Further studies that evaluate the effect of well-characterised and standardised preparations of ginseng in virologically proven influenza infections or more typical common cold illnesses will be needed to confirm and extend the results of the study reported in this issue,” he says.
The standardised ginseng extract described comprised 80 per cent poly-furanosyl-saccharides and 10 per cent protein formulated from the roots of North American ginseng. The capsules contained 200mg of freeze-dried extract.
Citation: The Pharmaceutical Journal URI: 10019455
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