Colorectal Cancer Risk Linked to Red and Processed Meat Consumption
According to research presented at the 2013 Annual American Society of Human Genetics meeting, individuals with certain a genetic variant who eat red or processed meats may elevate their colorectal cancer risk.
Genetics and Cancer
By Russ Allen, Publisher, Empowered Doctor
Genetics are foundational to the understanding, prevention and treatment of cancer. Genes are found in every cell of your body, and are essential to cell function. Mutations in genes lead to cancer.
These mutations usually come from one of two sources: heredity or lifestyle. Examples of gene mutations from lifestyle include poor diet choices, smoking or overexposure to UV rays via tanning beds. This type of mutation is called an acquired mutation. Conversely, and much less common, a mutation can be a part of a person’s cells from birth. These mutations are typically passed on from parent to child, and are called a germline mutations.
In this particular study, they have found an hereditary gene mutation that makes a person more susceptible to a specific lifestyle variable-- red and processed meat consumption.
Details of the Study Presented at the Annual American Society of Human Genetics 2013 Meeting.
Lead author of the study was Jane Figueiredo, Ph.D., Assistant Professor of Preventive Medicine at the Keck School of Medicine of the University of Southern California. Ulrike Peters, Ph.D., M.P.H, was senior author of the study, and is a member of the Fred Hutchinson Cancer Research Center’s Public Health Sciences Division.
The study evaluated 9,287 patients with colorectal cancer and a cancer free control group of 9,117 individuals without cancer. The study was sponsored by the National Institutes of Health-funded Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) and Colorectal Cancer Family Registry.
Although the study was initially reported at the 2013 Annual American Society of Human Genetics Meeting, it was also published recently in an April 2014 edition of PLOS Genetics.
The study searched 2.7 million genetic variants to identify which ones are associated with the consumption of meat, fiber, fruits and vegetables. They detected a significant interaction between the genetic variant rs4143094 and processed meat consumption. This variant is present in one out of three people, so the finding is quite impactive. This variant is located on the chromosome 10 region that includes a transcription factor gene known as GATA3, which plays a role in the immune system. This gene has been previously linked to several other forms of cancer as well.
How does red and processed meat consumption create a susceptibility to colorectal cancer? Researchers speculate that when the body digests these foods, it creates an immunological or inflammatory response. In a person without the genetic variant, the body is able to overcome this response. However, when an individual has the genetic variant it can encode a dysregulated transcription factor, making it hard for their body to overthrow the response.
Even in individuals without the genetic variant, an excess amount of red and processed meat in the diet is generally regarded as an unhealthy practice. According to Jane Figuerido, lead author of the study, "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."
Figuerido also commented “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.”
The study did not make a specific recommendation on the amount of red or processed meat that would be appropriate in a healthy diet, but the American Heart Association has recommended limiting red meat consumption to no more than 6-ounces per day.
What you should know about Genetic Testing
So how do you know if you have the genetic variant that leads to this increased sensitivity to the effects of eating red and processed meat? Predictive gene testing is a form of genetic testing that can be performed to determine if you have a specific gene mutation. This form of testing is performed most often in individuals who have a family history of a certain kind of cancer, and may be at high risk.
If you do not have a family history of colorectal cancer, you are probably safe to simply limit your consumption of red and processed meat to a moderate level, and increase your intake of fruits and vegetables. However, if you have a family history of colorectal cancer, genetic testing is something you may wish to pursue.
Bear in mind that genetic testing is a relatively new field of preventative medicine, and as such, may not be covered by your health insurance. Before you make the decision for genetic testing, you will need to determine the cost, and whether your insurance will cover it.
Genetic testing is often done through the services of a genetic counselor, who is specially trained not only to understand the results of genetic testing, but in how to process the complex emotions that may arise if one is found to be at high genetic risk for a certain cancer.
If you make the decision to undergo genetic testing, the procedure will require a specimen of your blood, cheek cells, urine, amniotic fluid (the fluid that surrounds a fetus during pregnancy), or other body tissues. Blood is the most common for cancer testing. It may take several weeks to get the results back from the lab.
Once the results are in, your doctor or genetic counselor will review the results, and the implication of those results with you. He or she will discuss the implications of the finding, including best lifestyle practices and dietary recommendations.
It is important to understand that even if you do not have a genetic predisposition to a specific cancer, it does not mean that you will not develop cancer at some point. A significant number of cancers are the results of gene mutations caused by lifestyle choices and other factors in the body, not by hereditary factors.Disclaimer
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