Background: Chemotherapy-induced nausea and vomiting (CINV) is among the most distressing cancer treatment side effects, affecting 20-70% of patients despite routine antiemetic prescription. Although routinely used in clinical practice, there is lack of data synthesis to determine which dietary strategies for CINV are supported by quality evidence.
Aim: To examine the effect of non-nutraceutical dietary strategies on incidence and severity of CINV in adults compared with no intervention, usual care, or alternative strategies.
Methods: Five databases were searched from inception to July 2021 for studies of interventional or observational design. The quality of evidence was appraised using the Academy of Nutrition and Dietetics Quality Criteria Checklist. Data were synthesized narratively and GRADE assessment of the certainty of evidence was applied.
Results: Twenty-one studies were included with 33% having low risk of bias. An association was found between improved CINV and alcohol intake; ginger tea; adequate energy, protein, fat, and carbohydrate; Mediterranean diet; and CINV-specific dietitian consultations or written information. A positive non-significant association was found between CINV and intake of grape juice and non-CINV specific dietitian consultations. No association was found for restricting oils, processed meats, fruits, vegetables, and dairy products; a colourless odorless diet; fasting with or without ketogenic diet; eating small frequent meals or avoiding food odours; and dietary education from an inpatient kitchen assistant or cancer nurse. The GRADE level of evidence was very low-to-low for most outcomes.
Conclusions: Improved CINV was associated with non-restrictive dietary strategies that promote adequate energy and macronutrient intakes, particularly protein, and include ginger, Mediterranean diet concepts, and moderate alcohol intake. Dietary strategies may best be implemented with ongoing education and support from a dietitian specific to CINV. However, future trials with adequate sample sizes, clearly defined dietary strategies, and valid outcome measures are warranted prior to being routinely prescribed alongside antiemetics.