title: Colonocyte telomere shortening is greater with dietary red meat than white meat and is attenuated by resistant starch.
abstract: OBJECTIVE
  Population studies indicate that greater red meat consumption increases colorectal cancer risk while dietary fibre is protective. Previous work in rats showed that diets high in protein, including red meat, increase colonocyte DNA strand breaks and that this effect is attenuated by resistant starches (RS). Telomeres are long hexamer repeats that protect against spontaneous DNA damage which would lead to chromosomal instability. Telomere shortening is associated with greater risk of colorectal cancer. The current study aimed to determine the effects of cooked red and white meat intake on colonocyte telomere length in rats and whether dietary RS modified their effects.
  
  
  METHODS
  After four weeks of feeding cooked beef or chicken at 15, 25 and 35% of diet with or without RS, colonocyte telomere length was measured.
  
  
  RESULTS
  Telomere length decreased in proportion to red meat content of the diet. A similar trend was observed in the white meat group. Colonocyte telomere shortening due to increased dietary meat was attenuated by the inclusion of RS.
  
  
  CONCLUSIONS
  These data support previous findings of increased colonocyte DNA damage with greater red and white meat intake and also the protective effect of dietary fibre.
authors.affiliation: Nutritional Genomics and DNA Damage Research Group, CSIRO Food and Nutritional Sciences, Kintore Avenue, PO Box 10041, Adelaide, SA 5000, Australia. nathan.ocallaghan@csiro.au
authors.forename: Nathan J
authors.initials: NJ
authors.lastname: O'Callaghan
authors.forename: Shusuke
authors.initials: S
authors.lastname: Toden
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Bird
authors.forename: David L
authors.initials: DL
authors.lastname: Topping
authors.forename: Michael
authors.initials: M
authors.lastname: Fenech
authors.forename: Michael A
authors.initials: MA
authors.lastname: Conlon
mesh_terms: D000818:Animals; D002417:Cattle; D002645:Chickens; D003106:Colon / Q000503:physiopathology; D003296:Cooking; D004249:DNA Damage; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004043:Dietary Fiber / Q000008:administration & dosage; D008297:Male; D008315:Malondialdehyde / Q000032:analysis / Q000378:metabolism; D008460:Meat; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D012044:Regression Analysis; D017422:Sequence Analysis, DNA; D013213:Starch / Q000008:administration & dosage*; D059506:Telomere Shortening
chemical_list: D004040:Dietary Carbohydrates; D004043:Dietary Fiber; D008315:Malondialdehyde; D013213:Starch