Most of us try to live in a manner we consider healthy, and nutritious food is probably among the first steps we attempt in our journeys towards better wellness.
We’re aware of the presence of macro and micro nutrients, and know that cooking techniques make a difference in how much nutrition is retained in our food.
Nutrient Absorption
Have you wondered though, where those are nutrients absorbed into our bodies? Here’s a quick reference.1–3
- Our gastrointestinal (GI) tract facilitates the transport of nutrients throughout its length.
- The small intestine is 2.5 to 3cm in diameter, and about 6m in length.
- The colon is 6 to 7.5cm in diameter and about 1.5m in length.
- The GI tract processes about 8 to 10 liters of fluid each day.
- Most of this fluid is handled by the small intestine, with about 1.5 liters managed by the colon and about 100ml excreted.
- Absorption of most nutrients takes place in the small intestine, including sugars, proteins, fat, water and fat soluble vitamins and water itself.
- The colon mostly handles water and electrolytes (sodium, potassium, calcium, magnesium and chloride among others) including the fluid that is released from the small intestine.
How Much Water Can We Drink?
I drink a great deal of water, and one day the question arose, how much water of that I drink is actually absorbed by the body? The question was of maximum effective dosage, i.e. of the water I drink how much is usable and how much is discarded, as the body must have capacities in this regard.
As it turns out, there are capacities involved. 4,5
The absorption rate of the small intestine and the colon are different, though when taken as a whole, the intestines can absorb a maximum of 13.6 ml of fluid per minute or about 2400ml every three hours. Keep in mind that this was tested with an electrolyte solution, which probably had higher rates of absorption than regular water. The presence of Glucose for instance, promotes the absorption of water and sodium may aid in the re-hydration process. 6
This would mean drinking about 500 to 800ml every hour of water with a pinch of sugar and salt is likely to be well utilized.
References
- 1.Kiela P, Ghishan F. Physiology of Intestinal Absorption and Secretion. Best Pract Res Clin Gastroenterol. 2016;30(2):145-159. doi:10.1016/j.bpg.2016.02.007
- 2.Chen L, Tuo B, Dong H. Regulation of Intestinal Glucose Absorption by Ion Channels and Transporters. Nutrients. 2016;8(1). doi:10.3390/nu8010043
- 3.SANDLE GI. Salt and water absorption in the human colon: a modern appraisal. Gut. Published online August 1, 1998:294-299. doi:10.1136/gut.43.2.294
- 4.Palma R, Vidon N, Bernier JJ. Maximal capacity for fluid absorption in human bowel. Digest Dis Sci. Published online October 1981:929-934. doi:10.1007/bf01309499
- 5.Davis G, Santa A, Morawski S, Fordtran J. Development of a lavage solution associated with minimal water and electrolyte absorption or secretion. Gastroenterology. 1980;78(5 Pt 1):991-995. https://www.ncbi.nlm.nih.gov/pubmed/7380204
- 6.Leiper J. Intestinal Water Absorption – Implications for the Formulation of Rehydration Solutions. Int J Sports Med. Published online June 1998:S129-S132. doi:10.1055/s-2007-971977
