A common genetic variant that affects 1 in every 3 people significantly increases their risk of colorectal cancer from the consumption of red meat and processed meat, according to a study presented at the 2013 American Society of Human Genetics meeting.
In addition to the identification of a gene that raises the risk for colorectal cancer from eating red or processed meat, the study also found another specific genetic variation that appears to modify whether or not eating more vegetables, fruits and fiber actually lowers your risk of colorectal cancer.
"Diet is a modifiable risk factor for colorectal cancer. Our study is the first to understand whether some individuals are at higher or lower risk based on their genomic profile. This information can help us better understand the biology and maybe in the future lead to targeted prevention strategies," said lead author Jane Figueiredo, Ph.D., Assistant Professor of Preventive Medicine at the Keck School of Medicine of USC.
"But we are not saying that if you don't have the genetic variant that you should eat all the red meat you'd like," Figueiredo added. "People with the genetic variant allele have an even higher increased risk of colorectal cancer if they consume high levels of processed meat, but the baseline risk associated with meat is already pretty bad."
Researchers systematically searched through more than 2.7 million genetic sequences for interactions with consumption of red and processed meats. The study looked at 9,287 patients with colorectal cancer and a control group of 9,117 individuals without cancer.
The risk of colorectal cancer associated with processed meat appeared to be significantly higher among people with the genetic variant rs4143094, the study found. The transcription factor encoded by this gene typically plays a role in the immune system, but 36 percent of the population has this variant. The researchers believe the digestion of processed meat may promote an immunological or inflammatory response that can trigger tumor development.
"Colorectal cancer is a disease that is strongly influenced by certain types of diets," Figueiredo said. "We're showing the biological underpinnings of these correlations, and understand whether genetic variation may make some people more or less susceptible to certain carcinogens in food, which may have future important implications for prevention and population health."