Dietary fibres include –
**Core Concept**
Dietary fibers are complex carbohydrates that are not digested by enzymes in the small intestine, but rather fermented by the gut microbiota in the large intestine. They play a crucial role in promoting satiety, regulating blood sugar levels, and preventing constipation.
**Why the Correct Answer is Right**
The correct answer is cellulose, a type of dietary fiber that is abundant in plant cell walls. Cellulose is a polysaccharide composed of beta-glucose units, which are resistant to digestion by human enzymes. Instead, it is fermented by the gut microbiota, producing short-chain fatty acids that provide energy to the colonocytes. This process also helps to soften stool and promote regular bowel movements.
**Why Each Wrong Option is Incorrect**
**Option A:**
This option is incorrect because pectin is a type of soluble fiber found in the cell walls of fruits, particularly in the skin and core. While it is a dietary fiber, it is not the correct answer.
**Option B:**
This option is incorrect because glycogen is a complex carbohydrate stored in the liver and muscles, serving as a readily available source of energy. It is not a dietary fiber.
**Option C:**
This option is incorrect because starch is a type of complex carbohydrate composed of glucose units. While it is a carbohydrate, it is not a dietary fiber.
**Clinical Pearl / High-Yield Fact**
A high-fiber diet can help to reduce the risk of diverticulitis, a condition characterized by inflammation of the diverticula in the large intestine. This is because dietary fiber helps to soften stool and promote regular bowel movements, reducing the pressure on the intestinal walls.
**Correct Answer:** C.