How long is it before a meal reaches the large intestine? The answer to such commonly asked question is not necessarily simple.
First, there is considerable normal variability among healthy people in transit times through different sections of the gastrointestinal tract. Second, the time required for material to move through the digestive tube is significantly affected by the composition of the meal. Finally, transit time is influenced by such factors as psychological stress, drug use and abuse, chemicals in the food and even gender and reproductive status.
- Substances do not move uniformly through the digestive system.
- Materials do not exit segments of the digestive tube in the same order as they arrive.
In other words, a meal is typically a mixture of chemically and physically diverse materials. Some of those substances in the mixture of foods accelerate transit while others are retarded in their flow downstream.
The points above should help to explain why it is difficult to state with any precision how long ingesta remains in the stomach, small intestine and large intestine. Nonetheless, there have been many studies on GI transit, and the table below presents rough estimates for transit times in healthy humans following ingestion of a standard meal (i.e. solid, mixed foods).
|50% of stomach contents emptied||2.5 to 3 hours|
|Total emptying of the stomach||4 to 5 hours|
|50% emptying of the small intestine||2.5 to 3 hours|
|Transit through the colon||30 to 40 hours|
I know some people don’t empty their stomach daily and that’s not a healthy condition which can bring about serious illnesses.
Remember that these are estimates of average transit times, and there is a great deal of variability among individuals and in the small person at different times and after different meals.
- Camilleri M, Colemont LJ, Phillips SF, etc. Human gastric emptying and colonic filling of solids characterized by a new method. Am J Physiol Gastrointest Liver Physiol. 257:284, 1989.
- Charles F, Camilleri M, Phillips SF, etc. Scintigraphy of the whole gut: clinical evaluation of transit disorders. Mayo Clinic Proc 70:113, 1995.
- Degen LP and Phillips SF. Variability of gastrointestinal transit in healthy women and men. Gut 39:299, 1996.
- Iwanaga Y, Wen J, Thollander MS, etc. Scintigraphic measurement of regional gastrointestinal transit in the dog. Am J Physiol Gastrointest Liver Physiol 275:904, 1998.
Metcalf AM, Phillips SF, Zinsmeister AR, etc. Simplified assessment of segmental colonic transit.
- Gastroenterology 92:40, 1987.
Proano M, Camilleri M, Phillips SF, etc. Transit of solids through the human colon: regional quantification in the unprepared bowel. Am J Physiol Gastrointest Liver Physiol 258:856, 1990.
- Surgery Today 1992, Volume 22, Issue 4, pp 386-389
© Copyright – Hector Sectzer