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Background and purpose: Pelvic radiotherapy (RT) often results in gastrointestinal toxicity and clinical trials have demonstrated a potential benefit of dietary supplements in alleviating acute effects. However, no prophylactic agents have been approved to date for relief of gastrointestinal side-effects caused by pelvic radiation. In this systematic review, we evaluated the efficacy of dietary supplements in preventing or alleviating symptoms of gastrointestinal toxicity in patients undergoing pelvic RT. Materials and methods: CENTRAL, MEDLINE, EMBASE, and were searched up to June 2020 for randomised controlled trials. Interventions included four supplement categories: biotics, glutamine, poly-unsaturated fatty acids and polyphenols. Efficacy was determined with reference to outcomes based on symptoms of acute gastrointestinal toxicity, including diarrhoea, nausea, vomiting, flatulence/bloating, bowel movement frequency, tenesmus and rectal bleeding. Results: Twenty-three randomised controlled trials (1919 patients) were identified in this review. Compared with placebo, probiotics (RR = 0.71; 95% CI: 0.52 to 0.99), synbiotics (RR = 0.45; 95% CI: 0.28 to 0.73) and polyphenols (RR = 0.30; 95% CI: 0.13 to 0.70) were significantly associated with a lower risk of diarrhoea. Biotic supplements also reduced the risk of moderate to severe diarrhoea (RR = 0.49; 95% CI: 0.36 to 0.67) and the need for anti-diarrhoeal medication (RR = 0.64; 95%CI: 0.44 to 0.92). In contrast, glutamine had no effect on acute symptoms (RR = 1.05; 95% CI: 0.86 to 1.29). There was a non-significant trend for reduction in nausea and mean bowel movements per day using dietary supplements. Conclusions: Biotic supplements, especially probiotics and synbiotics, reduce acute symptoms of gastrointestinal toxicity in patients undergoing pelvic radiotherapy.

Original publication




Journal article


Clin Transl Radiat Oncol

Publication Date





11 - 19


Biotics, Dietary supplements, Gastrointestinal toxicity, Meta-analysis, Pelvic radiotherapy, Systematic review