Document Detail


The gastrointestinal tract: a major site of antioxidant action?
MedLine Citation:
PMID:  11237104     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Diets rich in fruits and vegetables delay the onset of many age-related diseases, and contain a complex mixture of antioxidants (including ascorbate, carotenoids, vitamin E and other phenolics such as the flavonoids). However, diet also contains pro-oxidants, including iron, copper, H2O2, haem, lipid peroxides and aldehydes. Nitrite is frequently present in diet, leading to generation of reactive nitrogen species in the stomach. In considering the biological importance of dietary antioxidants, attention has usually focussed on those that are absorbed through the gastrointestinal tract into the rest of the body. In the present paper we develop the argument that the high levels of antioxidants present in certain foods (fruits, vegetables, grains) and beverages (e.g. green tea) play an important role in protecting the gastrointestinal tract itself from oxidative damage, and in delaying the development of stomach, colon and rectal cancer. Indeed, carotenoids and flavonoids do not seem to be as well absorbed as vitamins C and E. Hence their concentrations can be much higher in the lumen of the GI tract than are ever achieved in plasma or other body tissues, making an antioxidant action in the GI tract more likely. Additional protective mechanisms of these dietary constituents (e.g. effects on intercellular communication, apoptosis, cyclooxygenases and telomerase) may also be important.
Authors:
B Halliwell; K Zhao; M Whiteman
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Free radical research     Volume:  33     ISSN:  1071-5762     ISO Abbreviation:  Free Radic. Res.     Publication Date:  2000 Dec 
Date Detail:
Created Date:  2001-03-09     Completed Date:  2001-05-31     Revised Date:  2005-11-16    
Medline Journal Info:
Nlm Unique ID:  9423872     Medline TA:  Free Radic Res     Country:  Switzerland    
Other Details:
Languages:  eng     Pagination:  819-30     Citation Subset:  IM    
Affiliation:
Dept. of Biochemistry, National University of Singapore, Singapore.
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MeSH Terms
Descriptor/Qualifier:
Animals
Antioxidants* / administration & dosage,  therapeutic use
Carotenoids / therapeutic use
Diet
Flavonoids / therapeutic use
Gastrointestinal Diseases / prevention & control*
Gastrointestinal Neoplasms / prevention & control
Humans
Chemical
Reg. No./Substance:
0/Antioxidants; 0/Flavonoids; 36-88-4/Carotenoids

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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