Originally Posted by
terrymorse
Mechanisms of red meat consumption's causal link to colorectal cancer:
- Heme iron in red meat -> oxidative stress -> chronic cellular injury -> cell turnover -> malignancy
- High animal fat intake -> bile acids -> cellular injury -> malignancy
- Altered microbiome -> pro-inflammatory bacteria -> cellular injury -> malignancy
Cross et al 2010 is a well-respected large cohort study of the colorectal cancer risks from red and processed meats, with a break-out of the potential mechanisms.
7-year hazard ratios:
- red meat 1.24
- processed meat 1.16
- heme iron 1.12
- nitrate from processed meats 1.16
- heterocyclic amine intake 1.19, 1.17
NOTE: "Cohort study, eh? What about this confounding variable I just thought about?" Study was adjusted for: gender, education, BMI, smoking, intake of total energy, fiber and calcium consumption.
It was a rhetorical question... If a causal mechanism had been identified for red meat, then it would have been for sure classified as a class 1 carcinogen. Also note that it can make it to class 1 without ever establishing a causal mechanism, but just by evidence that are considered very strong.
It is impossible to have complete knowledge of all confounders, and the adjustments themselves carry errors anyway.
This reads more like a ChatGPT-based sequence of logical leaps.