The effects of dietary advice on malnutrition in Cancer patients: a systematic review and meta-analysis

Background: The effect of dietary advice on malnutrition in cancer patients is unclear. The aim of this systematic review was to evaluate the effects of dietary advice in cancer patients who were malnourished or at risk of malnutrition. Methods: Seven electronic databases were searched for randomized controlled trials (RCTs) of dietary counseling intervention in cancer patients with malnutrition or at risk of malnutrition. The studies were selected according to the inclusion and exclusion criteria and were critically appraised and abstracted by two researchers individually. Effect sizes were presented as weighted mean differences (WMD) or risk ratio (RR) with 95% confidence intervals (95%CI). Results: Six RCTs (737 participants) were included in meta-analysis. Comparing to usual care, dietary advice given by dieticians could not reduce mortality (RR = 1.11, 95%CI = 0.95 to 1.29) and body weight (WMD = 4.28 kg, 95%CI = − 0.21 to 8.76 kg) in cancer patients who were malnourished or at risk of malnutrition, but it was associated with statistically significant improvements in energy intake (WMD = 230.23kCal, 95%CI: 171.49 to 288.98), and quality of life (WMD = 37.92, 95%CI: 23.14 to 52.70). Conclusions: There remains insufficient evidence to conclude the actual effect of dietary advice given by dieticians in malnourished patients with cancer. Meta-analysis suggested that dietary advice given by dietitians may have no effect on mortality and body weight in patients with cancer who are malnourished, but it may be effective for improving QoL and energy intake. Studies with adequate participants and a clear low risk of bias are required to improve accuracy and confidence of conclusions.