Efficacy of ginger (zingiber officinale) in ameliorating chemotherapy-induced nausea and vomiting and chemotherapy-related outcomes: a systematic literature review update and meta-analysis

Nausea affects upwards of 60% of chemotherapy patients. Ginger has long been used in traditional medicine for alleviating nausea and vomiting; however, its use as an adjuvant therapy in patients undergoing chemotherapy is under‐researched. Therefore, a systematic literature review and meta‐analysis was undertaken to evaluate the efficacy of ginger supplementation in the prevention and management of chemotherapy‐induced nausea and vomiting. Five electronic databases were searched from database inception to October 2017. Intervention studies which administered ginger supplementation and a control (placebo or anti‐emetic) to adults receiving chemotherapy were included, critically appraised using the Cochrane Risk of Bias tool, and pooled using meta‐analysis. Seventeen papers were included. Ginger supplementation of any dose or duration had no effect on overall nausea incidence (OR: 0.80 [95% CI: 0.50–1.30] P = 0.37). There were trends towards improved nausea incidence for ginger supplementation of > 3‐days (OR: 0.54 [95% CI: 0.23–1.23] P = 0.14; n = 5 studies; I2 = 67%) and of doses > 1 g/day (OR: 0.56 [95% CI: 0.21–1.51] P = 0.25; n = 4 studies; I2=67%). Ginger supplementation appeared to be more effective for acute nausea (OR:0.73 [95% CI: 0.50–1.06] P = 0.10; n = 4 studies; I2 = 57%) than delayed nausea (OR:1.03 [95% I:0.76–1.39] P = 0.87; I2 = 20%). Ginger administration for > 3‐days significantly reduced overall vomiting incidence (OR: 0.58 [95% CI: 0.38–0.90] P = 0.01; n = 5 studies; I2 = 74%) and delayed vomiting incidence (OR: 0.44 [95% CI: 0.25–0.78] P = 0.005; n = 3 studies; n = 239 participants; I2 = 83%). Sensitivity analysis did not explain the substantial heterogeneity in the pooled outcomes. Ginger supplementation of > 1 g/day for > 3‐days may improve chemotherapy‐induced nausea and vomiting incidence; however, existing research remains inconsistent. Further research using strong designs, adequate sample sizes and standardized ginger products is warranted prior to routine clinical prescription.