| Diet and cell growth modulation by ammonia. | |
| | |
MedLine Citation:
|
PMID: 707376 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Fiber is not digested by endogenous enzymes but is fermented by microbes principally in the large intestine. With fermentable energy available, microbes synthesize protein by using ammonia released by their enzymes from urea and other nitrogenous substances in ingesta and intestinal secretions. Fibber fermentation also yields fatty acids that lower the concentration of free ammonia by lowering pH. Fiber increases bulk and water of intestinal contents, shortens transit time, and decreases the concentration of toxic substances in contact with the intestinal mucosa. These processes decrease duration and intensity of exposure of the intestinal mucosa to free ammonia, the form of nitrogen that is most toxic and most readily absorbed by cells. At concentrations found in the lower bowel on usual Western diets, ammonia destroys cells, alters nucleic acid synthesis, increases intestinal mucosal cell mass, increases virus infections, favors growth of cancerous cells over noncancerous cells in tissue culture, and increases virus infections. Ammonia in the bowel increases as protein intake increases. The attributes of ammonia and the epidemiological evidence comparing populations that maintain low intakes of unrefined carbohydrate with those that consume high intakes of protein, fat, and refined carbohydrates implicate ammonia in carcinogenesis and other disease processes. |
| | |
Authors:
|
W J Visek |
Related Documents
:
|
1996606 - Functional biology of intestinal goblet cells. 16909916 - Paneth cell alpha-defensin synthesis and function. 19225886 - Expression of resistin-like molecule beta in barrett's esophagus: a novel biomarker for... 42196 - Epithelial cell kinetics in the descending colon of the rat. i. the effect of ischaemia... 21374446 - Light microscopy : overview and basic methods. 174086 - Cytoplasmic microtubules in normal and transformed cells in culture: analysis by tubuli... |
Publication Detail:
|
Type: Journal Article |
Journal Detail:
|
Title: The American journal of clinical nutrition Volume: 31 ISSN: 0002-9165 ISO Abbreviation: Am. J. Clin. Nutr. Publication Date: 1978 Oct |
Date Detail:
|
Created Date: 1978-12-20 Completed Date: 1978-12-20 Revised Date: 2004-11-17 |
Medline Journal Info:
|
Nlm Unique ID: 0376027 Medline TA: Am J Clin Nutr Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: S216-S220 Citation Subset: AIM; IM |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Ammonia
/
metabolism*,
toxicity Animals Carcinogens Cellulose* Dietary Fiber* Fermentation Food Habits Humans Intestine, Large / metabolism, microbiology Rabbits |
| Chemical | |
Reg. No./Substance:
|
0/Carcinogens; 7664-41-7/Ammonia; 9004-34-6/Cellulose |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Dietary fiber and lymphatic absorption of cholesterol in the rat.
Next Document: Metabolism of biliary steroids by human fecal flora.