A new paper in the journal Cancer Discovery has uncovered fresh details about the link between eating red meat and the risk of colorectal cancer.
The study, led by Dana-Farber Cancer Institute oncologist Marios Giannakis has now identified specific patterns of DNA damage triggered by diets rich in red meat—further implicating the food as a carcinogen while heralding the possibility of detecting the cancer early and designing new treatments.
“When we say red meat is carcinogenic, and that it impacts incidence of cancer, there has to be some plausible way by which it does it,” Dana-Farber Cancer Institute oncologist Marios Giannakis, who led the new study, told a news agency.
Scientists discovered long ago which chemicals in cigarette smoke are to blame for cancer, and how certain bands of UV light penetrate the skin and trigger mutations in genes that control how cells grow and divide.
However, there has been a lack of clarity around how red causes cells to mutate.
To address the knowledge gap, Giannakis and his colleagues sequenced DNA data from 900 patients with colorectal cancer, who were drawn from a much larger group of 280,000 health workers participating in a years-long studies that included lifestyle surveys.
The analysis revealed a distinct mutational signature—a pattern that had never before been identified but was indicative of a type of DNA damage called “alkylation.”
Not all cells that contain these mutations will necessarily become cancerous, and the signature was present in some healthy colon samples too.
“With red meat, there are chemicals that can cause alkylation,” explained Giannakis.
The specific compounds are nitroso compounds that can be made from heme, which is plentiful in red meat, as well as nitrates, often found in processed meat.
The mutation patterns were strongly associated with the distal colon—the lower part of the bowels that leads to the anal canal, which is where past research suggested colon cancer linked to red meat mostly occurs.
But Giannakis, also a practicing doctor, said it was important to focus on how the research can be used to help patients.
Future work might help physicians identify which patients are genetically predisposed to accumulating alkylation damage, then counsel them to limit their red meat intake.
Identifying patients who have already started to accrue the mutational signature could help identify who’s at greater risk of developing cancer, or catch the disease at an earlier stage.