Increasing dietary rice bran and navy bean intake for colorectal cancer control and prevention: A randomized-controlled pilot investigation
Tuesday, November 3, 2015
: 8:45 a.m. - 9:00 a.m.
Background: The World Cancer Research Fund has estimated that 30–40% of all cancers can be prevented by appropriate diet and body weight, and a tremendous need exists for effective dietary chemoprevention strategies that can reach a diverse global population. People who consume whole grains and legumes are repeatedly highlighted for having increased longevity and lower burden of major chronic diseases. Staple foods, such as rice bran (RB) and navy beans (NB) represent affordable, available, and accessible foods with compelling data to inhibit colon carcinogenesis and reduce risk of developing colorectal cancer (CRC). Although these foods have demonstrated compelling chronic disease fighting properties in animal and human studies, only a small fraction of RB produced is used for human consumption and NB consumption remains low in the United States. BENEFIT (Beans/Bran Enriching Nutritional Eating For Intestinal health Trial) is a community-academic partnership to advance dietary RB and NB chemoprevention research in northern Colorado (NCT01929122). Our main objectives were to pilot the feasibility of increased consumption in CRC survivors and to examine changes in dietary intake, stool microflora, and stool and plasma metabolome. Materials and Methods: A total of 29 CRC survivors completed the three-arm, single-blinded, randomized-controlled, 4-week dietary intervention trial consuming study provide meals and snacks that included either dietary RB (30 g/day), NB (35 g/day), or neither. Blood, urine, saliva, and stool samples were collected at baseline, 2-week, and 4-week time points for metabolomic and microbiome analyses. Additionally, participants recorded a 3-day dietary food log each week on study. Results: We achieved 80-100% intervention compliance and participants consumed an average range of 4-9% daily caloric intake from RB or NB in prepared meals and snacks. Total dietary fiber intake was significantly increased in RB and NB diet groups at week 4 compared to baseline (p=0.0028 and p<0.0001, respectively), as well as compared to control at week 4 (p=0.0013 and p=0.0008, respectively). Pilot stool microflora of 15 survivors’ stool microbiome (5 participants per group) analyzed using 16S Illumina showed significant changes at the phylum level in Firmicutes, Bacteroidetes, Actinobacteria, and Verrucomicrobia. Blood plasma metabolite analysis detected more than 1000 compounds. A majority of the detected blood metabolite compounds responded to sex and age and roughly 20% responded to diet. Gut microbial metabolism of RB and NB will also be identified through stool metabolite profile analysis. Conclusions: These results suggest unique phytochemicals and nutrient profiles of RB and NB may modulate nutrient bioavailability and utilization, as well as stool microbiome composition and function. Specifically, this study established feasibility of increase RB or NB intake in CRC survivors and significantly increased total dietary fiber intake over time in these diet intervention groups. Our pilot findings warrant further evaluation of biomarkers of uptake and excretion for these specific foods in a larger cohort for CRC control and prevention.
Chronic disease management and prevention
Explain how increased consumption of staple foods, such as dry beans and whole grains, merit public health attention for colorectal cancer control and prevention.
Demonstrate economically feasible solutions that address health disparities in chronic disease prevention through dietary recommendations with staple foods.
Discuss human microbiome and metabolome research strategies relevant to public health nutrition and dietary interventions.
Keyword(s): Nutrition, Cancer Prevention and Screening
Presenting author's disclosure statement:
Qualified on the content I am responsible for because: I coordinated this dietary intervention trial in colorectal cancer survivors for secondary cancer prevention, as well as developed public health research activities with a focus on staple foods (e.g. whole grains and dry beans) and their contribution to healthy lifestyles. I have co-authored several articles that include an overall concept of disease prevention and control through improved gut health via whole foods.
Any relevant financial relationships? No
I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines,
and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed
in my presentation.