Mediterranean Diet and Weight Loss: Targeting the Bile Acid/Gut Microbiome Axis to Reduce Colorectal Cancer
University of Illinois at Chicago
Summary
A Mediterranean Diet (MedDiet), a largely plant-based dietary pattern, is relevant to CRC prevention and microbial production of anti-cancer metabolites in observational studies. A MedDiet can shift BA metabolism as shown in primates and when combined with calorie restriction, shows superior adherence and weight control in humans, given its palatability. To date, no studies have tested in an RCT the effects of a MedDiet alone (MedA), WL through lifestyle intervention (WL-A) or a calorie-restricted MedDiet for WL (WL-Med) on the BA-gut microbiome axis and its relevance to CRC prevention among AAs. A multidisciplinary team combining expertise in psychology, nutrition, microbiology, molecular cell biology, computational biology, medicine and biostatistics, proposes to conduct a four-arm RCT in which 232 obese AAs, 45-75 years old complete one of the following 6-month interventions: Med-A, weight stable; WL-A, calorie restriction with no diet pattern change; WLMed; or Control. The investigators will use samples and data collected at baseline, mid-study (month-3) and post-intervention to compare the effects of the interventions on 1) Concentration and composition of circulating and fecal BAs; 2) Gut microbiota and metabolic function; and 3) Gene expression profiles of exfoliated intestinal epithelial cells.
Description
Colorectal cancer (CRC) is associated with multiple risk factors including, obesity, low fiber diets, and diets high in animal protein and saturated fat (SFat). African Americans (AAs) have a higher prevalence of these risk factors and they have the highest incidence of CRC and related mortality. These multiple risk factors are also linked to higher circulating and fecal bile acids (BA) and a shift in BA amino acid conjugation from glycine to taurine. These BA-related changes can alter the composition, structure, and metabolic activity of the gut microbiota, fostering conditions for gut bacter…
Eligibility
- Age range
- 45–75 years
- Sex
- All
- Healthy volunteers
- Yes
Inclusion Criteria: * Men and women 45-75 years of age * Self-identify as AA * BMI 30-50 kg/m2 * Willingness to participate in all procedures including maintaining weight/current physical activity if randomized to Med-A/Control * Willingness and ability to provide informed consent * Willingness to be randomized * Understands English * Has access to a phone * Plans to reside in Chicago for the next 8-10 months. Exclusion Criteria: * renal disease * autoimmune disorders * immunodeficiency * malabsorptive disorders * significant gastrointestinal and/or hepatic diseases * severe ischemic heart…
Interventions
- OtherMed
Mediterranean diet
- OtherWL
Measuring change in weight
Location
- University of Illinois at ChicagoChicago, Illinois