Haem, not protein or inorganic iron, is responsible for endogenous intestinal N-nitrosation arising from red meat.
Many N-nitroso compounds (NOC) are carcinogens. In this controlled study of 21 healthy male volunteers, levels of NOC on a high (420 grams) red meat diet were significantly greater (P = 0.001) than on a low (60 grams) meat diet but not significantly greater when an equivalent amount of vegetable protein was fed. An 8-mg supplement of haem iron also increased fecal NOC (P = 0.006) compared with the low meat diet, but 35-mg ferrous iron had no effect. Endogenous N-nitrosation, arising from ingestion of haem but not inorganic iron or protein, may account for the increased risk associated with red meat consumption in colorectal cancer.
Cross
Amanda Jane
AJ
Medical Research Council, Dunn Human Nutrition Unit, Wellcome Trust/MRC Building, Cambridge CB2 2XY, United Kingdom.
Pollock
Jim R A
JR
Bingham
Sheila Anne
SA
D000328:Adult; D000368:Aged; D000818:Animals; D002417:Cattle; D018592:Cross-Over Studies; D019587:Dietary Supplements; D005243:Feces / Q000737:chemistry; D006418:Heme / Q000494:pharmacology*; D006801:Humans; D007420:Intestine, Large / Q000187:drug effects / Q000378:metabolism*; D019266:Iron, Dietary / Q000494:pharmacology*; D008297:Male; D008460:Meat / Q000009:adverse effects*; D008875:Middle Aged; D009573:Nitrites / Q000378:metabolism; D009603:Nitroso Compounds / Q000378:metabolism*
D019266:Iron, Dietary; D009573:Nitrites; D009603:Nitroso Compounds; D006418:Heme