Reviewed: Kun YP, Kyung JC, Shan RC, et al. Non-organ-specific preventive effect of long-term administration of Korean red ginseng extract on incidence of human cancers. J Med Food. 2011;13(3):489-494.

The authors’ goal in this trial was to accumulate evidence that supports cancer prevention through the use of natural therapies. To date, common cancer treatments include early detection, surgery, radiotherapy, chemotherapy, and gene therapy. The new strategy is moving toward preventative approaches aimed at reducing the incidence of all cancers. Due to the high incidence of stomach cancer in chronic atrophic gastritis patients over the duration of their disease, such patients present a beneficial population in which to study the anti-carcinogenic effects of Korean red ginseng (Panax ginseng, Araliaceae).*

Animal research on mice has confirmed the anti-carcinogenic properties of Korean ginseng.¹ Human studies, including a case-control study of 1810 participants, reported Korean ginseng reduced the risk of all types of cancer.² These results suggest that Korean ginseng exhibits a non-organ-specific preventative effect against cancer.

Ginsenosides in ginseng have been found to play an active role in cancer prevention and therapy. Rg3 and Rg5 reduced the incidence of benzo[a]pyrene-induced lung tumors.³ Rg3 activated nuclear factor κB and extracellular signal-regulated kinase, inhibited cell proliferation, and induced apoptosis.⁴ Further studies are needed to fully appreciate the constituents responsible for the effect of Korean ginseng on cancer cells. However, combined animal/human research and molecular mechanism studies give a good indication of benefit from the inclusion of Korean ginseng in cancer preventive treatment.

Chronic atrophic gastritis patients have a 5.73-fold higher development of stomach cancer than other individuals. This randomized, double-blind, placebo-controlled study sought to confirm the cancer-preventative effects of Korean ginseng with 643 male and female patients, recruited from 4 hospitals in China, aged 40-69 years, with this gastric disease. The duration of the study was 11 years: 3 years of supplementation with Korean ginseng, followed by 8 years of follow-up. The patients were randomly given 4 x 250 mg capsules per week for 3 years of 6-year-old ginseng root extract powder prepared by Korea Ginseng Corp (Seoul, Korea). The powdered extract was prepared by steaming fresh (“white”) ginseng roots at 100°C for 2.5-3.0 hours. The roots were then dried. Once dry, the roots were boiled for 3 hours and centrifuged (600 g, 30 minutes), then concentrated until the water content reached 36%. The concentrated extract was dissolved in water, dried in a spray-dryer, and encapsulated as red ginseng extract powder.^† The control group was given 4 x 250 mg capsules of a rice powder placebo per week for 3 years.

Relative risks (RRs) were calculated using Cox proportional hazards and logistic regression models. The RRs and confidence intervals (CIs) of the ginseng and placebo groups were adjusted for factors including sex, age, smoking, alcohol consumption, family history of cancer, and history of ginseng use. The results showed an RR of 0.54 for the ginseng group compared to the placebo group. The CI was 0.23-1.28, which was non-significant (P=0.13); for men only, the RR was 0.35 (CI 0.13-0.96), which was significant (P=0.03).

Twenty-four cancer cases occurred out of the 643 patients who participated over the 11-year study. The cumulative morbidity risk was much higher at 2.84-fold in the placebo group with 16 cancer cases compared to only 8 cancer cases from the ginseng group. Twenty-one cancer cases were in males.

There were only mild adverse side effects documented for the duration of the trial in the ginseng group, including headaches. The percentage of gastrointestinal symptoms between both groups was almost identical with 55.0% in the placebo group and 57.3% in the ginseng group. This symptom can be attributed to the patients’ gastric disease.

The authors do not discuss their observation that the number of stomach cancer cases in the 2 groups was the same (3 cases per group). The study thus did not appear to have a chemopreventive impact on what would seem to be the disease for which atrophic gastritis patients are most at risk—stomach cancer. However, this is a small population for a chemoprevention study. No calculation of statistical power for the study or figures on projected incidence of stomach cancer is given.

The study’s results suggest a non-organ-specific cancer preventative effect of Korean red ginseng and coincide with findings from other studies. One study reported that in 905 pairs of patients, various organ cancer risk decreased by half (RR=0.56) with the use of ginseng.² In an extended study with the same 905 pairs of patients included in a total of 1,987 pairs, Korean red ginseng reduced the cancer risk of all organs.⁵ A similar study with 4,634 Korean subjects also found red ginseng to have a cancer preventative effect in all organ cancers.⁶ Based on this research, Korean red ginseng root appears to be a promising adjunct to a healthy lifestyle and preventative therapy to reduce the occurrence of all cancer types.