Fiber’s Impact on Colorectal Cancer and Diabetes
Beneficial Effects of Fiber on Colorectal Cancer
Populations that consume more fiber have a lower incidence of colorectal cancers. Diets low in fat and high in fiber (cereals, fruits, and vegetables) reduce the risk of this type of cancer.
Fiber, Food, and Diabetes
Glycemic Index (GI): A measure of the ability of foods to increase blood glucose levels after meals.
Daily Intake: Aim for an insoluble/soluble fiber ratio of 3:1.
- Breakfast: Cereal, fruit, jam.
- Lunch and Dinner: Increase vegetable intake with vegetable soups, salads, pasta, and whole wheat bread.
- Dessert: Choose a piece of fresh fruit.
Options to Increase Fiber:
- Replace white flour with whole wheat flour.
- Eat whole grain products.
Advantages of Fiber from Fruits and Vegetables over Cereal Fiber
- More balanced composition between soluble and insoluble fiber.
- Lower calorie content.
- Higher water-holding capacity.
- Increased fermentability.
Role of Intestinal Microflora
Probiotics: “Live microbial food ingredients that are beneficial to health.”
Common probiotic species include Lactobacillus and Bifidobacterium. A probiotic must:
- Be a microorganism usually found in the human gastrointestinal tract.
- Survive intestinal transit.
- Be able to grow and colonize the intestine.
- Provide beneficial health effects.
Intestinal Colonization
The stomach’s pH acts as a barrier to Gram-positive bacteria like Lactobacillus and Streptococcus. Transient bacteria, such as 14 of 15 strains, lost 90% viability during gastric transit. Adding milk protein improves gastric transit. L. casei and Bifidobacterium infantis are pH resistant. In the small intestine, bacterial adhesion to epithelial cells is specific; other non-intestinal bacteria are needed for penetration and binding to the mucosa.
The administration of bifidobacteria in fermented milk promotes an increase of beneficial intestinal bacteria. Colonic flora may be altered by eating foods containing probiotics; colonic flora modifies the host’s metabolism.
Malabsorption Syndromes
Steatorrhea: >30g fat/day in stool.
Causes and Treatment:
- Liver disease decreases the production of bile acids, reducing fat absorption. Treatment: Low-fat diet.
- Cystic fibrosis. Treatment: Supplementation with pancreatic enzymes and fat-soluble vitamins altered to be easily absorbed.
- Defects in the intestinal mucosa, i.e., celiac disease. Treatment: Avoid foods with gluten.
- Crohn’s disease (inflammation of the ileum and colon). Treatment: A diet low in fat and high in fiber.
Astringent Diet
Diarrhea involves an increased intestinal transit rate and fluid stools, 15-20 times daily, abundant and compelling.
Recommendations:
- Avoid fiber, which increases intestinal transit and enhances peristalsis.
- Remove milk, which contains lactose and may lead to prolonged digestion.
- Eat small, frequent meals to avoid peristalsis.
- Avoid stews, stir-fries, sausages, and cured meats, as they irritate the gastrointestinal mucosa.
- Limit fat intake due to prolonged digestion.
- Remove coffee and orange juice because sugar enhances peristalsis.
It is a progressive diet:
- Phase I: For the first 6-24 hours, prohibit eating (depending on the severity of the situation). This is called NPO (nothing by mouth).
- Phase II: Start a liquid diet (water, rice water, boiled carrots, etc.), approximately 125 cc every 2-4 hours.