Biology:Metabolic water
Metabolic water refers to water created inside a living organism through metabolism, by oxidizing energy-containing substances in food and adipose tissue. Animal metabolism produces about 107–110 grams of water per 100 grams of fat,[1] 41–42 grams of water per 100 g of protein, and 60 grams of water per 100 g of carbohydrate.[2][1][3]
Some organisms, especially xerocoles — animals living in the desert — rely exclusively on metabolic water. Migratory birds must rely exclusively on metabolic water production while making non-stop flights, facilitated by the high metabolic rate during such flights.[4][5] Humans, by contrast, obtain only about 8–10% of their water needs through metabolic water production.[6]
In mammals, the water produced from metabolism of protein roughly equals the amount needed to excrete the urea which is a byproduct of the metabolism of protein.[6] Birds, however, excrete uric acid and can have a net gain of water from the metabolism of protein.
References
- ↑ 1.0 1.1 Mellanby, Kenneth (July 1942). "Metabolic Water and Desiccation". Nature 150 (3792): 21. doi:10.1038/150021a0. Bibcode: 1942Natur.150...21M.
- ↑ Morrison, S. D. (1953-11-28). "A method for the calculation of metabolic water". The Journal of Physiology 122 (2): 399–402. doi:10.1113/jphysiol.1953.sp005009. ISSN 0022-3751. PMID 13118549.
- ↑ Medicine, Institute of; Board, Food Nutrition; Intakes, Standing Committee on the Scientific Evaluation of Dietary Reference; Water, Panel on Dietary Reference Intakes for Electrolytes and (2005). 4 Water | Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate | The National Academies Press. pp. 85. doi:10.17226/10925. ISBN 978-0-309-09169-5. https://www.nap.edu/read/10925/chapter/6#85.
- ↑ "Racing the wind. Water economy and energy expenditure in avian endurance flight". http://dissertations.ub.rug.nl/faculties/science/2005/s.b.engel/.
- ↑ Klaassen M (1996). "Metabolic constraints on long-distance migration in birds". J Exp Biol 199 (Pt 1): 57–64. doi:10.1242/jeb.199.1.57. PMID 9317335. http://jeb.biologists.org/cgi/pmidlookup?view=long&pmid=9317335.
- ↑ 6.0 6.1 Board on Agriculture and Natural Resources (BANR), Nutrient Requirements of Nonhuman Primates: Second Revised Edition (2003), p. 144. [1]
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