Effects of a Rice Bran Dietary Intervention on the Composition of the Intestinal Microbiota of Adults with a High Risk of Colorectal Cancer: A Pilot Randomised-Controlled Trial

Nutrients. 2021 Feb 6;13(2):526. doi: 10.3390/nu13020526.


Rice bran exhibits chemopreventive properties that may help to prevent colorectal cancer (CRC), and a short-term rice bran dietary intervention may promote intestinal health via modification of the intestinal microbiota. We conducted a pilot, double-blind, randomised placebo-controlled trial to assess the feasibility of implementing a long-term (24-week) rice bran dietary intervention in Chinese subjects with a high risk of CRC, and to examine its effects on the composition of their intestinal microbiota. Forty subjects were randomised into the intervention group (n = 19) or the control group (n = 20). The intervention participants consumed 30 g of rice bran over 24-h intervals for 24 weeks, whilst the control participants consumed 30 g of rice powder on the same schedule. High rates of retention (97.5%) and compliance (≥91.3%) were observed. No adverse effects were reported. The intervention significantly enhanced the intestinal abundance of Firmicutes and Lactobacillus, and tended to increase the Firmicutes/Bacteroidetes ratio and the intestinal abundance of Prevotella_9 and the health-promoting Lactobacillales and Bifidobacteria, but had no effect on bacterial diversity. Overall, a 24-week rice bran dietary intervention was feasible, and may increase intestinal health by inducing health-promoting modification of the intestinal microbiota. Further larger-scale studies involving a longer intervention duration and multiple follow-up outcome assessments are recommended.

Keywords: colorectal cancer; dietary intervention; intestinal health; intestinal microbiota; rice bran.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Colorectal Neoplasms / microbiology
  • Colorectal Neoplasms / prevention & control*
  • Diet, Healthy / methods*
  • Dietary Fiber / administration & dosage*
  • Double-Blind Method
  • Eating / physiology
  • Feasibility Studies
  • Feces / microbiology
  • Female
  • Gastrointestinal Microbiome / physiology*
  • Humans
  • Male
  • Middle Aged
  • Oryza*
  • Pilot Projects
  • Risk Factors


  • Dietary Fiber