Ginseng and Cancer
Several case-control and prospective cohort studies conducted in a Korean population suggest that ginseng intake can reduce the risk of cancer, though this was not supported by other cohort studies in
Ginseng is an herb that includes Asian ginseng (Panax ginseng) and American ginseng (Panax quinquefolius), both of which have been used for their medicinal properties.1
Though various types of ginseng extracts or derivatives have shown anticancer properties in human cancer cell lines, there are no published clinical trials evaluating ginseng's efficacy in a human population. Ginseng has, however, been studied as a chemopreventive and an agent to improve quality of life among patients with cancer.
Risk of Cancer
A study of 905 cancer cases and 905 controls conducted in Korea suggested that ginseng intake significantly reduced cancer incidence (odds ratio [OR], 0.56; 95% CI, 0.45-0.69), with greater efficacy seen with ginseng extract and powder compared with fresh slices, juice, or tea.2
Patient recall for ginseng-use was good, with an 85% agreement of ginseng-use between 2 different interviews. Another case-control study of 1987 pairs showed a significant association between ginseng-use and reduced cancer risk (OR, 0.50; 95% CI, 0.44-0.58).3 Though fresh extract or any preparation of white/red ginseng were effective, the greatest association was observed with red ginseng extract (OR, 0.20; 95% CI, 0.08-0.50).
These data were supported by results from a prospective study of 4634 Korean subjects aged 40 or older.4 In this study, ginseng-use resulted in a significant reduction in cancer incidence compared with non-use (relative risk [RR], 0.40; 95% CI, 0.28-0.56), demonstrating a dose-response relationship in which higher intake or greater frequency of ginseng-use was associated with a greater reduction in cancer incidence.
The RR among ginseng users vs nonusers was 0.33 (95% CI, 0.18-0.57) for gastric cancer and 0.30 (95% CI, 0.14-0.65) for lung cancer. These studies were followed by a randomized, double-blind trial in which 643 patients with chronic atrophic gastritis received red ginseng extract or placebo for 3 years, with follow-up for up to 8 years.5 Red ginseng-use resulted in a lower risk of any cancer compared with placebo (RR, 0.54; 95% CI, 0.23-1.28; P = .13), which was significant among male subjects (RR, 0.35; 95% CI, 0.13-.096; P = .03).
Several epidemiologic studies evaluated the use of ginseng and cancer incidence. An analysis of 74,942 women aged 40 to 70 at baseline from the Shanghai Women's Health Study found no association between ginseng-use — including white, red, American, or other ginseng types — and an increased or decreased risk of gastric cancer.6 An analysis of 35,239 men aged 50 to 76 from the Vitamins and Lifestyle (VITAL) cohort study similarly found no association between ginseng-use and an increased or decreased risk of prostate cancer.7