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.

Figures

Figure 1

Participation and recruitment into the study based on the CONSORT Statement guidelines.

Figure 2

Beans/Bran Enriching Nutritional Eating For Intestinal Health Trial study design overview.

Figure 3. Feasibility of dietary intervention that includes consumption of 35 g/day NB powder or 30 g/day RB

(a) Calculated percent intake at baseline, week 2, and week 4. (b) Gastrointestinal health questionnaire responses from sixteen BENEFIT participants.

Figure 3. Feasibility of dietary intervention that includes consumption of 35 g/day NB powder or 30 g/day RB

(a) Calculated percent intake at baseline, week 2, and week 4. (b) Gastrointestinal health questionnaire responses from sixteen BENEFIT participants.

Figure 4. Correlation analyses between telomere length and other participant characteristics at baseline and week 4 that were significant or were near-significant

(a) Significant correlations between telomere length and age (p=0.003), HDL-cholesterol (p=0.04), and near-significant correlation with LPS (p=0.071) at baseline. Baseline telomere lengths were analyzed for correlations between age, sex, BMI, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, CRP, SAA, and LPS for all participants regardless of diet intervention group. Age, HDL-cholesterol, and LPS variables showed high correlation with telomere length levels across time points. (b) Non-significant correlation between telomere length and SAA at baseline (p=0.77) and significant correlation at week 4 (p=0.027). SAA was the only variable in the correlation analysis with telomere length that became significant at week 4 across entire study cohort.

Figure 4. Correlation analyses between telomere length and other participant characteristics at baseline and week 4 that were significant or were near-significant

(a) Significant correlations between telomere length and age (p=0.003), HDL-cholesterol (p=0.04), and near-significant correlation with LPS (p=0.071) at baseline. Baseline telomere lengths were analyzed for correlations between age, sex, BMI, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, CRP, SAA, and LPS for all participants regardless of diet intervention group. Age, HDL-cholesterol, and LPS variables showed high correlation with telomere length levels across time points. (b) Non-significant correlation between telomere length and SAA at baseline (p=0.77) and significant correlation at week 4 (p=0.027). SAA was the only variable in the correlation analysis with telomere length that became significant at week 4 across entire study cohort.

Figure 5. Percent change from baseline to week 4 of selected nutrients across diet groups (*

=Significant to control group; p<0.05)