Wheat aleurone flour increases cecal beta-glucuronidase activity and butyrate concentration and reduces colon adenoma burden in azoxymethane-treated rats.
Processed wheat aleurone flour (WAF) is a source of insoluble fermentable dietary fiber that comes from the outer layers of the wheat kernel. A study was designed to evaluate WAF, wheat bran (WB) and alpha-cellulose as the source of dietary fiber (5 g/100 g of diet) in a semipurified high fat (20 g/100 g of as 1:1 lard/sunflower seed oil) diet fed to male Sprague-Dawley rats in which intestinal tumors were induced using azoxymethane (AOM). WAF at 33 g/100 g of diet (WAF33) and WB at 16 g/100 g of diet (WB16) increased the weight of feces and produced significantly higher concentrations in the cecum of the short-chain fatty acid butyrate (P < 0.001) than did no fiber (NF) and WAF added at only 10 g/100 g (1.5 g of dietary fiber) (WAF10). Cecal and fecal pH were both significantly lower in the WAF33 and WB16 treatments relative to control and no fiber treatments (P < 0.001). The intestinal tumors in the rats were assessed at 6 mo after the study began, and the WAF33- or WB16-fed rats showed a trend (P = 0.06) with 43% fewer colon adenomas relative to control. There was a significant inverse relationship between ss-glucuronidase activity and colon adenomas in the rat colon (r2 = 0.37, P = 0.001). WAF fiber influenced some metabolic markers of fermentation in the colon in a manner similar to that of WB, which, independent of the bulking effect, was associated with a trend to reduced colon adenomas. Significantly increased cecal ss-glucuronidase activity and/or butyrate concentrations may have protective influences in this context by mechanisms not yet fully elucidated.
McIntosh
G H
GH
CSIRO Health Sciences and Nutrition, Adelaide, SA 5000, Australia.
Royle
P J
PJ
Pointing
G
G
D000236:Adenoma / Q000139:chemically induced / Q000473:pathology*; D000818:Animals; D001397:Azoxymethane; D002087:Butyrates / Q000378:metabolism*; D002273:Carcinogens; D002432:Cecum / Q000378:metabolism*; D002482:Cellulose; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000473:pathology*; D004043:Dietary Fiber / Q000494:pharmacology; D005243:Feces / Q000737:chemistry; D005285:Fermentation; D005433:Flour; D005966:Glucuronidase / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014908:Triticum
D002087:Butyrates; D002273:Carcinogens; D004043:Dietary Fiber; D002482:Cellulose; D005966:Glucuronidase; D001397:Azoxymethane