A new gene variant found increases the risk of colorectal cancer from eating processed meat such as cold cuts, bacon, processed ham, pastrami, corned beef, mortadella, lutefisk, smoked salmon, smoked turkey, and hot dogs. The key word when it comes to meat is processed as in deli cold cuts or grilled hot dogs. But do you have the gene variant? That common genetic variant affecting one in three people appears to significantly increase the risk of colorectal cancer from the consumption of processed meat, according to a new study, "Genome-Wide Diet-Gene Interaction Analyses for Risk of Colorectal Cancer, " published April 17, 2014 in PLOS Genetics. The study of more than 18,000 people from the U.S., Canada, Australia and Europe represents the first large-scale genome-wide analysis of genetic variants and dietary patterns that may help explain more of the risk factors for colorectal cancer.
Eating processed meat is associated with an increased risk of colorectal cancer
Dr Jane Figueiredo at the Keck School of Medicine of the University of Southern California, explained that eating processed meat is associated with an increased risk of colorectal cancer and for about a third of the general population who carry this genetic variant, the risk of eating processed meat is even higher compared to those who do not.
"Our results, if replicated by other studies, may provide us with a greater understanding of the biology into colorectal carcinogenesis," said Dr Ulrike Peters of the Fred Hutchinson Cancer Research Center's Public Health Sciences Division, according to the April 17, 2014 news release, "New gene variant found increases the risk of colorectal cancer from eating processed meat."
The study population totaled 9,287 patients with colorectal cancer and a control group of 9,117 individuals without cancer, all participants in 10 observational studies that were pooled in the largest meta-analysis sponsored by the National Institutes of Health-funded Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) and Colorectal Cancer Family Registry.
Scientists systematically searched 2.7 million variants to identify those that are associated with the consumption of meat, fiber, fruits and vegetables
A significant interaction between the genetic variant rs4143094 and processed meat consumption was detected. This variant is located on the same chromosome 10 region that includes GATA3, a transcription factor gene previously linked to several forms of cancer. The transcription factor encoded by this gene plays a role in the immune system. Dr Figueiredo hypothesized that the genetic locus found to interact with processed meat may have interesting biological significance given its location in the genome, but further functional analyses are required.
Colorectal cancer is a multi-factorial disease attributed to both genetic causes and lifestyle factors; including diet. About 30 known genetic susceptibility alleles for colorectal cancer have been pinpointed throughout the genome. How specific foods affect the activities of genes has not been established but represents an important area of research for prevention.
"The possibility that genetic variants may modify an individual's risk for disease based on diet has not been thoroughly investigated but represents an important new insight into disease development," said Dr Li Hsu, according to the news release. Hsu is the lead statistician on the study.
"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 Dr Figueiredo, according to the news release.
Fish consumption advisories
An another new study, "Evaluating the Effectiveness of Fish Consumption Advisories: Modeling Prenatal, Postnatal, and Childhood Exposures to Persistent Organic Pollutants," recently published in the journal Environmental Health Perspectives, suggests that fish consumption advisories for expecting mothers are ineffective in reducing infant exposure to long-lived contaminants like persistent organic pollutants (POPs). The study, performed by a team of researchers including University of Toronto Scarborough PhD student Matt Binnington and Professor Frank Wania, looks at how different levels of environmental contamination, a mother’s compliance with advisories and the behavior of chemicals in the body influenced exposure in her children.
Their model estimates that women who stop eating fish shortly before or during their pregnancy may only lower their child’s exposure to POPs by 10 to 15 per cent. “We have to be careful in saying fish advisories don’t work at all because they can work very well for reducing exposure to quickly eliminated contaminants, such as mercury,” says Binnington, according to the April 17, 2014 news release, Fish consumption advisories fail to cover all types of contaminants. “But for POPs we found that they are not very effective.”
POPs are compounds that take a long time to break down and as a result can persist in the environment and begin to accumulate in humans by way of the food chain
While many POPs such as DDT and PCBs have long been banned from production, they still exist in the environment. Fish advisories have been developed for these chemicals because they are easily passed from mothers to their children during pregnancy and nursing, potentially impacting healthy infant neurodevelopment.
Binnington says consumption advisories for many POPs are ineffective because they can remain in the body for years or even decades due to properties that make it difficult for the human body to eliminate them. The same is not true for mercury-based advisories, as the time it remains in the body is much shorter compared to POPs.
By temporarily adjusting your diet, you can reduce exposure to some heavy metals
“Something like mercury stays in the body for only a few months and by temporarily adjusting your diet you can reduce exposure,” says Binnington, according to the news release. The limitation with consumption advisories is that while they inform people what not to eat, they do not offer much in the way of healthy alternatives, says Wania. In fact, substituting fish with meat such as beef may even end up doing more harm.
“Substituting fish with beef may actually result in higher exposure to other contaminants,” he says, according to the news release, adding there is also a loss of nutritional benefits by not eating fish. The research, which received funding through NSERC) and the Northern Contaminants Program (NCP) of the Canadian Department for Aboriginal Affairs and Northern Development (AANDC), is published in the journal Environmental Health Perspectives.