Systematic Reviews of Current Literature Fail to Establish Dietary Benzo[a]pyrene, Heterocyclic Aromatic Amines, or Heme Iron as Mechanisms Linking Red and Processed Meat Consumption with Cancer Risk

Dietary exposure to potentially high-risk compounds such as heterocyclic aromatic amines (HAAs) or the polycyclic aromatic hydrocarbon, benzo[a]pyrene (BaP), formed in meat during cooking, or from exposure to hemeiron naturally occurring in meat, have all been proposed as possible mechanisms responsible for the reported weak association between red and processed meat consumption and increased cancer risk in observational studies. In this study, a systematic review of the mechanistic literature was used to examine the available evidence-base to determine if sufficient evidence exists to link heme iron, BaP, or HAAs from red and processed meat to increased cancer risk. Inclusion criteria required that study designs accommodate exposure from a whole food or in the context of a well-described diet and that outcomes adequately represent normal physiology of the tissue of interest. Results regarding dietary Ba Prevealed, of 51 studies published since 2000, only 4 met the full criteria for inclusion. The primary...