Plasma and Urine Metabolite Profiles Impacted by Increased Dietary Navy Bean Intake in Colorectal Cancer Survivors: a randomized-controlled trial

Abstract

Navy beans contain bioactive phytochemicals with colon cancer prevention properties as demonstrated in carcinogen-induced animal models. Human studies support that dietary navy bean intake modulates metabolism by the gut microbiome. This study investigated the effect of navy bean ingestion on plasma and urine metabolite profiles of overweight and obese colorectal cancer (CRC) survivors. Twenty participants completed a single-blinded, randomized-controlled dietary intervention with pre-cooked navy beans (35g bean powder/day) or control (0g/day) for 4 weeks. Plasma and urine were collected at baseline, 2 weeks and 4 weeks following consumption. Non-targeted metabolomics was applied to study meals and snacks, navy beans, plasma, and urine. Increased navy bean consumption was hypothesized to a) delineate dietary biomarkers and b) promote metabolic shifts relevant for cancer protection in the plasma and urine metabolome. At 4 weeks, 16 plasma and 16 urine metabolites were significantly different in the navy bean intervention group compared to placebo-control (p< 0.05). Increased plasma 2,3-dihydroxy-2-methylbutyrate (1.34-fold), S-methylcysteine (1.92-fold), and pipecolate (3.89-fold), and urine S-adenosylhomocysteine (2.09-fold) and cysteine (1.60-fold) represent metabolites with cancer protective actions following navy bean consumption. Diet-derived metabolites were detected in plasma or urine and confirmed for presence in the navy bean intervention meals and snacks. These included 3-(4-hydroxyphenyl)propionate, betaine, pipecolate, S-methylcysteine, choline, eicosapentaenoate (20:5n3), benzoate, S-adenosylhomocysteine, N-delta-acetylornithine, cysteine, 3-(4-hydroxyphenyl)lactate, gentisate, hippurate, 4-hydroxyhippurate, and salicylate. The navy bean dietary intervention for 4 weeks showed changes to pathways of metabolic importance to CRC prevention and merit continued attention for dietary modulation in future high-risk cohort investigations.