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Whey proteins protect more than red meat against azoxymethane induced ACF in Wistar rats
journal contribution
posted on 2003-07-30, 00:00 authored by D P Belobrajdic, G H McIntosh, Julie OwensJulie OwensProtein type and density have been shown to influence colon cancer risk using a carcinogen-induced rat model. It is suggested that red meat may promote colon cancer risk more than whey proteins. The aim of this study was to evaluate the influence of red meat, whey protein and their density in the diet on the number of aberrant crypt foci (ACF), preneoplastic markers in Wistar rats. The sources of protein, red meat as barbecued kangaroo muscle meat, and whey protein concentrate were fed to rats to provide 8, 16 and 32% protein by weight in a modified AIN-93 diet with low fiber, low calcium and high polyunsaturated fat. Adult Wistar rats (13 weeks of age) were fed these diets for 4 weeks and then two s.c. injections of azoxymethane, 15 mg/kg BW, were administered 1 week apart. Diets were fed for a further 8 weeks, rats were then killed, their colons fixed in formalin saline and stained with methylene blue to quantify ACF number. Fecal samples were collected and the fecal water was isolated for quantification of heme and thiobarbituric acid reactive substances. Increasing red meat density correlated positively, while increasing dairy protein density correlated negatively with rate of weight gain (p<0.05). Dietary intake was not significantly affected by protein type or density. The 32% whey protein group had significantly less ACF in the proximal colon in comparison to the 16 and 32% red meat groups (p<0.05). This reduction in ACF number in the whey protein group may be caused by hormones associated with the reduction in weight gain, and/or by components of whey protein concentrate such as cysteine, lactose and conjugated linoleic acid which have been shown to have anti-cancer effects. Using ACF number as an index, whey protein appeared to be more protective than red meat.
History
Journal
Cancer lettersVolume
198Issue
1Pagination
43 - 51Publisher
ElsevierLocation
Amsterdam, The NetherlandsPublisher DOI
ISSN
0304-3835Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2003, Published by Elsevier Ltd.Usage metrics
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No categories selectedKeywords
AnimalsAzoxymethaneColonic NeoplasmsDietHemeMeatMilk ProteinsPrecancerous ConditionsRatsRats, WistarWhey ProteinsScience & TechnologyLife Sciences & BiomedicineOncologycolon canceraberrant crypt fociwhey proteinred meatprotein densityDIMETHYLHYDRAZINE-INDUCED MALIGNANCYCOLON CARCINOGENESIS MODELPLASMA GLUTATHIONE LEVELSCOLORECTAL-CANCER RISKHIV-INFECTED PATIENTSIMMUNOENHANCING PROPERTYANTIOXIDANT ACTIVITYIMMUNE-RESPONSESPEROXYL RADICALS
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