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

Background: Ginger has been proposed as an adjuvant treatment for chemotherapy-induced nausea and vomiting. Objective: The aim of this systematic review with meta-analyses is to evaluate, in adult cancer patients receiving chemotherapy, the effects of ginger supplementation dose and duration on the incidence, duration, and severity of chemotherapy-induced nausea and vomiting and outcomes related to chemotherapy-induced nausea and vomiting (eg, quality of life and fatigue), compared with placebo or standard antiemetic medication. Method: Five electronic databases were searched from database inception to April 2018. The quality of evidence was appraised with the Cochrane Risk of Bias tool and Grading of Recommendations, Assessment, Development, and Evaluation level. Data were pooled using Revman software. Results: Eighteen articles were analyzed. The likelihood of acute vomiting was reduced by 60% with ginger supplementation ≤1 g/day for duration >3 days, compared with control groups (odds ratio 0.4, 95% CI 0.17 to 0.81; P=0.01; n=3 studies; n=3 interventions; n=301 participants; I2=20%; Grading of Recommendations, Assessment, Development, and Evaluation level: Moderate). The likelihood of fatigue was reduced by 80% with ginger supplementation of any dose for duration <3 days (odds ratio 0.2, 95% CI, 0.03 to 0.87; P=0.03; n=1 studies; n=2 interventions; n=219 participants; I2=0%; Grading of Recommendations, Assessment, Development, and Evaluation level: Low). No statistically significant association was found between ginger and likelihood of overall or delayed vomiting, likelihood or severity of nausea, or other outcomes related to chemotherapy-induced nausea and vomiting. Conclusions: Ginger supplementation might benefit chemotherapy-induced vomiting as well as fatigue. Due to clinical heterogeneity, this systematic review update found no association between ginger and chemotherapy-induced nausea and other chemotherapy-induced nausea and vomiting-related outcomes. The results of this systematic review and meta-analysis provide a rationale for further research with stronger study designs, adequate sample sizes, standardized ginger products, and validated outcome measures to confirm efficacy of ginger supplementation and optimal dosing regimens.