Heat-stabilised rice bran consumption by colorectal cancer survivors modulates stool metabolite profiles and metabolic networks: a randomised controlled trial

Abstract

Rice bran (RB) consumption has been shown to reduce colorectal cancer (CRC) growth in mice and modify the human stool microbiome. Changes in host and microbial metabolism induced by RB consumption was hypothesised to modulate the stool metabolite profile in favour of promoting gut health and inhibiting CRC growth. The objective was to integrate gut microbial metabolite profiles and identify metabolic pathway networks for CRC chemoprevention using non-targeted metabolomics. In all, nineteen CRC survivors participated in a parallel randomised controlled dietary intervention trial that included daily consumption of study-provided foods with heat-stabilised RB (30 g/d) or no additional ingredient (control). Stool samples were collected at baseline and 4 weeks and analysed using GC-MS and ultra-performance liquid chromatography-MS. Stool metabolomics revealed 93 significantly different metabolites in individuals consuming RB. A 264-fold increase in β-hydroxyisovaleroylcarnitine and 18-fold increase in β-hydroxyisovalerate exemplified changes in leucine, isoleucine and valine metabolism in the RB group. A total of thirty-nine stool metabolites were significantly different between RB and control groups, including increased hesperidin (28-fold) and narirutin (14-fold). Metabolic pathways impacted in the RB group over time included advanced glycation end products, steroids and bile acids. Fatty acid, leucine/valine and vitamin B6 metabolic pathways were increased in RB compared with control. There were 453 metabolites identified in the RB food metabolome, thirty-nine of which were identified in stool from RB consumers. RB consumption favourably modulated the stool metabolome of CRC survivors and these findings suggest the need for continued dietary CRC chemoprevention efforts.

Comparative Rice Bran Metabolomics across Diverse Cultivars and Functional Rice Gene-Bran Metabolite Relationships

“…Rice bran variation in composition of bioactive molecules has functional relevance to rice breeders that seek to improve bran for human and animal health. The results of this study support the feasibility that numerous phytochemicals that have reported medicinal mechanisms of action can be improved in rice bran through breeding [13,14,95]. Rice bran, regardless of varietal differences, has a valuable 'core' metabolome as well as a variable set of metabolites that differ among cultivars, which can be developed as an affordable food ingredient for a diverse global population that remains challenged to meet basic nutritional security needs.…”

“…Polished white rice is the major product with rice milling yields of 65-70% and the by-products comprised of 20% rice husk and 8-12% rice bran [8]. Rice bran has a broad spectrum of health benefits [9][10][11][12], partially due to a diverse array of bioactive metabolites [13,14]. Rice bran bioactive components include, but are not limited to γ-oryzanol [15], tocopherols, tocotrienols [16], carotenoids [17], γ-aminobutyric acid [18], octacosanol [19], squalene [20], unsaturated fatty acids [21], phytosterols and phenolic compounds [22].…”

Navy Bean and Rice Bran Intake Alters the Plasma Metabolome of Children at Risk for Cardiovascular Disease

“…Power calculation for this pilot study was based on effect sizes reported in a previous rice bran dietary intervention metabolomics study ( 29 , 30 ). Two-way analysis of variance (ANOVA) and Welch’s two-sample t -tests were used to determine statistical significance between groups, and ANOVA with repeated measures was used to determine statistical significance within groups ( p ≤ 0.05).…”

The anti-cancer activity and potential clinical application of rice bran extracts and fermentation products

“…85 A heat-stabilized rice bran diet offers the benets of bacterial richness and diversity in the gut, helps with microbial metabolism, modulates stool metabolite proles, and contributes to chemoprevention in colorectal cancer survivors. [86][87][88] The function of rice bran in altering gut microbiota might contribute to the relief of adverse gastrointestinal effects in cancer patients during chemotherapy. A study that enrolled patients with cervical cancer indicated that the oral intake of hydrolyzed rice bran effectively attenuated the diarrheal side effects of chemotherapy.…”