title: Intake of beer inhibits azoxymethane-induced colonic carcinogenesis in male Fischer 344 rats.
abstract: Modulatory effects of beer consumption on azoxymethane (AOM)-induced rat colonic carcinogenesis in male Fischer 344 rats were investigated. Single cell gel electrophoresis assay indicated that DNA damage of colonocytes, induced by a single AOM injection (15 mg/kg body weight), was significantly reduced in rats fed beer or malt extract for 2 weeks. Examination of aberrant crypt foci (ACF) formation in colonic mucosa, induced by AOM (15 mg/kg body weight; twice weekly), revealed that feeding of beer during the whole experimental period of 5 weeks significantly reduced the number of ACF by 35%. In the post-initiation protocol, a reduction in ACF formation by 26% was not significant. The efficacy in inhibition of ACF formation varied with the brand of beer. ACF formation was significantly reduced in rats treated with freeze-dried beer (FD Beer), but not with ethanol, suggesting that nonvolatile components of beer are responsible for the reduction. Significant suppression of ACF formation was observed in groups treated with hot water extract of malt, especially with extracts of colored malts, although no reduction was observed by feeding with hops extract. A long-term experiment of 42 weeks indicated that intake of beer decreased tumor incidence by 22% and decreased the number of neoplastic lesions, including adenocarcinomas and adenomas, by 44%. These results suggest that components of beer have chemopreventive effects on colonic carcinogenesis induced by AOM and that intake of beer may contribute to a reduction in the risk of cancer susceptibility.
authors.affiliation: Central Laboratories for Key Technology, Kirin Brewery Co., Ltd., Yokohama, Japan. h-nozawa@kirin.co.jp
authors.forename: Hajime
authors.initials: H
authors.lastname: Nozawa
authors.forename: Aruto
authors.initials: A
authors.lastname: Yoshida
authors.forename: Osamu
authors.initials: O
authors.lastname: Tajima
authors.forename: Mikio
authors.initials: M
authors.lastname: Katayama
authors.forename: Hiromi
authors.initials: H
authors.lastname: Sonobe
authors.forename: Keiji
authors.initials: K
authors.lastname: Wakabayashi
authors.forename: Keiji
authors.initials: K
authors.lastname: Kondo
mesh_terms: D000230:Adenocarcinoma / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control; D000236:Adenoma / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control; D000284:Administration, Oral; D000818:Animals; D001397:Azoxymethane / Q000633:toxicity*; D001515:Beer; D001835:Body Weight / Q000187:drug effects; D002273:Carcinogens / Q000633:toxicity*; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000473:pathology; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D002273:Carcinogens; D001397:Azoxymethane