Insoluble fiber

Insoluble fiber does not dissolve in water. It does not get broken down by the bacteria in the large intestine. Since it passes essentially unchanged through the intestines, it produces little gas. Insoluble fiber, also known as roughage helps digestion by absorbing water in the intestine which results in smoother cleaning of the bowels. Cellulose, hemicellulose, and lignin are examples of insoluble fiber.

Detailed question

Diverticula are small sacs that occur on your large intestine (also called your colon). Some people think that they must stay away from eating seeds because these seeds can get stuck in the openings of these sacs. Can eating seeds develop or worsen diverticulosis?

Does eating seeds affect my condition of diverticulosis?

The majority of scientific literature does not support the hypothesis that by avoiding eating seeds you can avoid future attacks of diverticulitis.

Gut Bacteria

The microbial population of the gut, or gut microbiota is extremely dense, predominantly comprising bacteria. Whilst a core community of gut microbes—approximately one third—is common to most healthy adults, the composition of each gut microbiota varies according to factors including genetics, diet, age, state of health and geographical location. Microbes are considered important—but probably not essential—to digestion. This is primarily because the gut microbiota breaks down substances that the gut alone is unable to digest and is also involved in synthesis of vitamins.

Colon

The large intestine carries out the function of absorption of water and electrolytes as well as storing waste until it can be expelled. It is also responsible for maintaining water balance and some absorption of vitamins such as vitamin K. The mixture of remaining food and intestinal juices called chyme in the colon is devoid of almost all nutrients and water; it consists of primarily the undigested food with some amount of water and electrolytes.