Plasma, urine, and stool metabolites in response to dietary rice bran and navy bean supplementation in adults at high-risk for colorectal cancer

Abstract

IntroductionDietary intake of whole grains and legumes and adequate physical activity (PA) have been associated with reduced colorectal cancer (CRC) risk. A single-blinded, two-arm, randomized, placebo-controlled pilot trial was implemented to evaluate the impact of a 12-week dietary intervention of rice bran + navy bean supplementation and PA education on metabolite profiles and the gut microbiome among individuals at high risk of CRC.MethodsAdults (n=20) were randomized 1:1 to dietary intervention or control. All participants received PA education at baseline. Sixteen study foods were prepared with either heat-stabilized rice bran + navy bean powder or Fibersol®-2 as a placebo. Intervention participants consumed 30 g rice bran + 30 g navy bean powder daily; those in the control group consumed 10 g placebo daily. Non-targeted metabolite profiling was performed by UPLC-MS/MS to evaluate plasma, urine, and stool at 0, 6, and 12 weeks. Stool was also analyzed for primary and secondary bile acids (BAs) and short chain fatty acids (SCFAs) by UPLC-MS/MS and microbial community structure via 16S amplicon sequencing. Two-way ANOVA was used to compare differences between groups for metabolites, and mixed models were used to compare differences between groups for BAs, SCFAs, and alpha and beta diversity measures of microbial community structure.ResultsAcross biological matrices, the intervention resulted in changes to several amino acid and lipid metabolites, compared to control. There was a 2.33-fold difference in plasma (p<0.001) and a 3.33-fold difference in urine (p=0.008) for the amino acid S-methylcysteine at 12 weeks. Fold-differences to 4-methoxyphenol sulfate in plasma and urine after 6 and 12 weeks (p<0.001) was a novel result from this combined rice bran and navy bean intervention in people. A 2.98-fold difference in plasma (p=0.002) and a 17.74-fold difference in stool (p=0.026) was observed for the lipid octadecenedioylcarnitine at 12 weeks. For stool BAs, 3-oxocholic acid was increased at 12 weeks compared to control within a subset of individuals (mean difference 16.2 ug/uL, p=0.022). No significant differences were observed between groups for stool SCFAs or microbial community structure.DiscussionDietary intake of rice bran + navy beans demonstrates beneficial modulation of host and gut microbial metabolism and represents a practical and affordable means of increasing adherence to national guidelines for CRC control and prevention in a high-risk population.

Urine and Dried Blood Spots From Children and Pregnant Women Reveal Phytochemicals, Amino Acids, and Carnitine Metabolites as Cowpea Consumption Biomarkers

“…[21][22][23] Urine and dried blood spots (DBS) are ideal biological fluids to examine dietary exposures due to ease in collection and sensitivity to dietary metabolite abundance changes over time. [24] We recently reported on the cooked cowpea flour metabolome used in this child and pregnant women feeding study; the cowpea flour analysis demonstrated distinct metabolite profiles for cowpea flour compared to other legumes. [25] However, limited data exists for metabolite changes in biofluids following human consumption of cowpea flours and differing cowpea varieties.…”

Pilot Study of Heat-Stabilized Rice Bran Acceptability in Households of Rural Southwest Guatemala and Estimates of Fiber, Protein, and Micro-Nutrient Intakes among Mothers and Children

“…Additionally, rice bran components exhibit anti-oxidant, anti-diarrheal, and anti-inflammatory properties [11,12,[16][17][18], which may improve nutritional status by optimizing gut mucosal barrier function [19,20]. Rice bran modulates the gut microbiome and metabolome of children and adults [15,21,22] and has demonstrated protective effects against chronic disease, including colorectal cancer [23][24][25]. Thus, rice bran, if locally developed as a food ingredient, may serve as an affordable, available, accessible, and acceptable food option to help address the double burden of malnutrition; it helps prevent undernutrition while simultaneously providing metabolic support for the control and prevention of chronic diseases that result from overnutrition [11,21].…”