When meat is cooked at high temperatures, it produces substances that are carcinogenic in animal models. Processed meats also contain carcinogens.
Researchers assessed the diets and meat-cooking methods of nearly 3,700 patients with left-sided polyps (adenomas) and another 39,000 people who had colonoscopies but no polyps. The interview questionnaire was coordinated with existing data on the presence of heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), known carcinogenics in well-cooked meat.
They discovered an increased risk for left-sided colon, but not rectal, adenomas associated with meat HCA’s. A greater intake of bacon and sausage also increased risk for adenoma, but eating processed meats did not.
The research team concluded:
Our study of screening-detected colorectal adenomas shows that red meat and meat cooked at high temperatures are associated with an increased risk of colorectal adenoma.
Rashmi Sinha led a team of epidemiologists from the National Cancer Institute, Harvard Medical School, and the University of Pittsburgh.
SOURCE: Sinha et al., Cancer Research, Volume 65, pp. 8034-8041, September 1,2005.