Dietary Fibre

Question 1

Explain how high fiber diets reduce the risk of developing cancer in colon

Answer 1

1. 2 types of dietary fibers according to their water solubility: soluble and insoluble
2. A diet composed of adequate amount of both these fiber types ensures maintenance of a normal gut health
3. Fibers do not get metabolize in the gut so it increases bulk and binds the carcinogens ingested and produced along the digestive tract
4. Ensures rapid elimination of fecal matter from body and reduces exposure of toxic substances to the enterocytes
5. Soluble fibers get fermented by micro flora in the colon to produce butyrate and other short chain fatty acids
6. Butyrate is important in prevention of colon cancer and ulcerative colitis as it stimulates apoptosis of cancerous colon cells
7. } Through a high fiber diet that’s composed of both these fiber types would help reduce the risk of colon cancer development

Question 2

List the diseases that could be minimized by increasing the dietary fiber intake

Answer 2

1. Coronary heart disease
2. Stroke
3. Peptic ulcers
4. Diabetes
5. Gallbladder disorders
6. Constipation
7. Appendicitis
8. Colorectal cancer
9. Diverticular disease
10. Hiatus hernia
11. Hemorrhoids
12. Gastroesophageal reflux disease

Question 3

Explain the mechanism through which dietary fiber minimizes the prevalence of coronary heart disease (CHD)

Answer 3

1. Soluble of viscous fibers have hypocholesterolemia effect
2. Causes reduction of LDL without change in HDL or TAG
3. Fibers reduce cholesterol intake by promoting satiety, decreasing cholesterol absorption efficiency, increasing fecal bile acid and cholesterol excretion
4. Fermentation of fibers in colon produces short chain fatty acids that may contribute to hypocholesterolemia by reducing cholesterol synthesis
5. Reduces blood cholesterol and therefore atherosclerotic plaques which reduces incidence of CHD

Question 4

Dietary fibers are essential in maintaining a healthy colon. Explain the biochemical basis of this statement

Answer 4

1. Dietary fibers are resistant to digestion and absorption in the intestine and undergo fermentation partially or completely in the colon to produce short chain fatty acids
2. Colonic mucosal cells take up these as an energy source and maintain a healthy mucosal lining
3. Also reduces the risk of colorectal cancer by balancing intestinal pH
4. Fibers add bulk to the diet and hence the stools (maintaining the regularity by speeding up the passage of food through the gut)
5. Helps to reduce the risk of constipation, hemorrhoids, diverticular diseases etc.
6. Fiber contains prebiotics which induce growth of health promoting bacteria that influences the well-being of the host