A Randomized Controlled Trial to Increase Navy Bean or Rice Bran Consumption in Colorectal Cancer Survivors

ABSTRACT

Consumption of navy beans (NB) and rice bran (RB) have been shown to inhibit colon carcinogenesis. Given the overall poor diet quality in colorectal cancer (CRC) survivors and low reported intake of whole grains and legumes, practical strategies to increase consumption merit attention. This study determined feasibility of increasing NB or RB intake in CRC survivors to increase dietary fiber and examined serum inflammatory biomarkers and telomere lengths. Twenty-nine subjects completed a randomized controlled trial with foods that included cooked NB powder (35 g/day), heat-stabilized RB (30 g/day), or no additional ingredient. Fasting blood, food logs, and gastrointestinal health questionnaires were collected. The amount of NB or RB consumed equated to 4–9% of subjects' daily caloric intake and no major gastrointestinal issues were reported with increased consumption. Dietary fiber amounts increased in NB and RB groups at Weeks 2 and 4 compared to baseline and to control (P ≤ 0.01). Telomere length correlated with age and HDL cholesterol at baseline, and with improved serum amyloid A (SAA) levels at Week 4 (P ≤ 0.05). This study concludes feasibility of increased dietary NB and RB consumption to levels associated with CRC chemoprevention and warrants longer-term investigations with both foods in high-risk populations that include cancer prevention and control outcomes.

Acknowledgments

Funding for this study was provided by NIH 1R21CA161472, University of Colorado Cancer Center—Division of Cancer Prevention and Control, and the Dry Bean Health Research Group. The authors appreciate the University of Colorado Health-North Cancer Clinical Research group, specifically Joann Lovins and Erica Dickson, for helping with subject recruitment and assistance with study implementation. The authors thank Gordon Gregory from ADM Edible Bean Specialties and Dr. Anna McClung from the United States Department of Agriculture Agricultural Research Service (USDA-ARS) Dale Bumpers National Rice Research Center for supplying the cooked navy bean powders and heat-stabilized RB. They also thank Katie Schmitz, Genevieve Forster, Amy Sheflin, Cadie Tillotson, Allie Reava, Kerry Gundlach, and Brianna Nervig for technical support with meal and snack design and food preparations, and all our study subjects.

ORCID

Erica C. Borresen http://orcid.org/0000-0002-3049-5978