People differ in their definition of constipation but there are several features constituting satisfactory or unsatisfactory defecation. The call for the stool should be regular. Most subjects regard once or twice daily as preferable. Defecation should not require straining, nor take 15 minutes to achieve. Motions should be soft but formed and of reasonable bulk, about 150 to 200g wet weight. The stool should be passed without pain or discomfort, and, afterwards, there should not be a feeling of incomplete emptying of the rectum. A high fiber diet improves each of these bowel functions
The main constituent of feces is water which forms 70-80% of stool weight. The dry matter is predominantly unfermented fiber and bacteria.
On a low fiber diet the dry matter consists of about 36% protein and about 18% of each of the following; fats and sterols; minerals; short chain fatty acids and carbohydrates. On a high fiber diet the solid fractions may contain about 30% of carbohydrate, at least 70% of the total sugars are being in the form of cellulose, xylose and arabinose.
The magnitude of stool bulking by fiber depends on the source of the fiber. Dietary fibers may be considered as a hydrated spong passing along the gastrointestinal tract. Vegetables and fruits fibers (pectic and mucilaginous substances) with a water holding capacity (a measure of the ability to of a fiber to immobilize water in a matrix) of about 50g water per g, are more accessible for fermentation and therefore by themselves produce little change in the bulk of the stool. On the other hand, cereal fiber with low water holding capacity will be relatively inert in the aqueous medium of the gut, be less readily available for fermenatation andproduce a significant change in stool bulk. This ability is reduced when cereal bran is made more digestible to bacterial enzymes by fine grinding and cooking.
The colonic mucosa recovers sodium and water from the lumen. The colon absorbs about 5 liters of water per day. The only force resisting this is the osmotic pressure of gut contents. Bacterial metabolism results in small molecules with high osmotic pressure. If these substrates are also catabolised by bacteria, water will be absorbed readily. A slow continuous release of metabolites, by maintaining an osmotic gradient, could slow absorption of water, decrease MTT and increase fecal out put.
Further readings
What is constipation?
Common causes of constipation
Investigation of severe constipation
Treatment for constipation
Herbal medicine (complementary/alternative medicine) for constipation
The main constituent of feces is water which forms 70-80% of stool weight. The dry matter is predominantly unfermented fiber and bacteria.
On a low fiber diet the dry matter consists of about 36% protein and about 18% of each of the following; fats and sterols; minerals; short chain fatty acids and carbohydrates. On a high fiber diet the solid fractions may contain about 30% of carbohydrate, at least 70% of the total sugars are being in the form of cellulose, xylose and arabinose.
The magnitude of stool bulking by fiber depends on the source of the fiber. Dietary fibers may be considered as a hydrated spong passing along the gastrointestinal tract. Vegetables and fruits fibers (pectic and mucilaginous substances) with a water holding capacity (a measure of the ability to of a fiber to immobilize water in a matrix) of about 50g water per g, are more accessible for fermentation and therefore by themselves produce little change in the bulk of the stool. On the other hand, cereal fiber with low water holding capacity will be relatively inert in the aqueous medium of the gut, be less readily available for fermenatation andproduce a significant change in stool bulk. This ability is reduced when cereal bran is made more digestible to bacterial enzymes by fine grinding and cooking.
The colonic mucosa recovers sodium and water from the lumen. The colon absorbs about 5 liters of water per day. The only force resisting this is the osmotic pressure of gut contents. Bacterial metabolism results in small molecules with high osmotic pressure. If these substrates are also catabolised by bacteria, water will be absorbed readily. A slow continuous release of metabolites, by maintaining an osmotic gradient, could slow absorption of water, decrease MTT and increase fecal out put.
Further readings
What is constipation?
Common causes of constipation
Investigation of severe constipation
Treatment for constipation
Herbal medicine (complementary/alternative medicine) for constipation
0 comments:
Post a Comment