Fiber and Fish Oil Supplements for the Prevention of Colorectal Cancer

Diet and the Colonic Exfoliome: A Novel, Non-Invasive Approach to Testing Interventions in Humans

This trial studies how fiber and fish oil supplements affect the metabolism and activities of colon cells in healthy individuals. Diet is an important risk factor for colorectal cancer, and several dietary components important in colorectal cancer prevention are modified by gut microbial metabolism. Giving fiber and fish oil supplements may inhibit the growth of gut cells and ultimately reduce risk of colorectal cancer.

Participants are randomized to receive two dietary interventions in assigned random order. They either receive the dietary fiber supplement and fish oil supplement orally (PO) daily or they receive a fiber control and corn oil supplement daily for 30 days during the first intervention period. Then they enter a washout period for 60 days when they do not receive any treatment. After that they complete the second intervention period during which they receive the other intervention.

Inclusion Criteria:

• Healthy
• Normal-overweight (body mass index [BMI] of 18-30 kg/m^2)
• Women will be postmenopausal, with no menstrual period in 12 months
• Non-smoking
• Consume fiber intakes of less than < 20 g/d
• White blood cell count 3,000-11,000/mm^3
• Platelet count 100,000-400,000 mm^3
• Hematocrit 33-50% (women); 36-50% (men)
• Bilirubin 0.2-1.3 mg/dL
• Aspartate aminotransferase (AST) 0-35 U/L
• Alanine aminotransferase (ALT) 0-40 U/L
• Alkaline phosphatase 20-125 U/L
• Creatinine =< 1.2 mg/dL
• Potassium 3.5-5.0 mmol/L

Exclusion Criteria:

• Chronic medical illness, history of gastrointestinal disorders (e.g., ulcerative colitis, Crohn disease, celiac sprue, hereditary nonpolyposis colorectal cancer [HNPCC], familial adenomatous polyposis, pancreatic disease, previous gastrointestinal resection, radiation or chemotherapy, and cancer (other than non-melanoma skin cancer)
• Weight change greater than 4.5 kg within past year
• Oral or intravenous (IV) antibiotic use within the past 3 months
• Regular use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs)
• Smoking or use of cannabis products
• Known allergy to fish
• Intention to relocate out of study area within next 4 months