Red ginseng and H5N1 influenza infection

The recent report on “Red Ginseng and H5N1 influenza infection” in this journal is very interesting [1]. Park et al [1] noted that “the diet with the immune-enhancing Red Ginseng could help humans to overcome the infections by HP H5N1 influenza virus.” In fact, the effect of ginseng on immunomodulation has previously been confirmed and it has been proposed that ginseng can be useful in improving immunity to fight infection [2]. Lee et al [2] noted that ginseng can help to stimulate antiviral cytokine IFN-g production after influenza A virus infection and inhibit the infiltration of inflammatory cells into the bronchial lumen. Yoo et al [3] have reported that “red ginseng extract showed significantly enhanced protection, lower levels of lung viral titers and interleukin-6.” In-depth biochemical analysis has shown that the polysaccharide in the extract is the main part that contributes to the counteracting function towards the influenza virus [4]. In addition, it has also been reported that Red Ginseng extract could enhance the protection derived from influenza vaccination [5]. Hence, there is no doubt that ginseng as a food supplement can be useful against influenza. In human studies, some workers have reported that Red Ginseng can be useful in improving acute respiratory illness [6] as well as influenza-like illnesses [7]. In a study in humans, the protective effect of ginseng on human endothelial cells against avian influenza virus has been reported in vitro [8]. However, there has not yet been a reliable clinical trial on influenza in humans. There are still topics for further study, including: verification of the usefulness of ginseng extract in humans; standardization of the commercially available ginseng extracts; and the development of a health body which can give information to users about the effectiveness and safety of ginseng supplementation. As noted by Kaneko and Nakanishi [9], the effect of ginseng is mysterious and most data are from subjective clinical observations; further research on this topic is required. Finally, the safety of using ginseng in humans should also be mentioned. Although ginseng is considered safe, some rare adverse effects, such as anaphylaxis, have been reported [10]. In a human study evaluating the role of ginseng extract in potentiating the influenza vaccine, many adverse effects were recorded, especially insomnia [11].