Charring meat on a grill or in a pan has been thought to increase the formation of cancer-causing compounds for some time. Researchers linked increased consumption of meat cooked at high temperatures with an increased risk for renal cell carcinoma, or kidney cancer, in a new study.
The study comes on the heels of a large review of research by the World Health Organization that said processed meat such as bacon and sausage causes cancer, and that all red meat “probably” causes cancer.
Cooking meat at high temperatures or over an open flame can result in the formation of carcinogens such as 2-amino-1-methyl-6-phenyl-imidazo(4,5-b) pyridine, or PhIP, and amino-3,8-dimethylimidazo(4,5-f) quinoxaline, or MeIQx. The association with carcinogen formation has been found both in red and white meat.
Both chemicals can cause changes in DNA that results in the formation of RCC or other types of cancer, according to the National Cancer Institute.
Researchers at the University of Texas MD Anderson Cancer Center found the link in surveys of recently diagnosed kidney cancer patients, additionally finding the people with specific genetic variations may be more at risk for RCC than others.
“We found elevated RCC risk associated with both meat intake and meat-cooking mutagens, suggesting independent effect of meat-cooking mutagens on RCC risk,” said Dr. Xifeng Wu, a professor of epidemiology at the University of Texas, in a press release. “Our findings support reducing consumption of meat, especially meat cooked at high temperatures or over an open flame as a public health intervention to reduce RCC risk and burden.”
Researchers in the study surveyed eating patterns and collected genetic information for 659 people with renal cell carcinoma and 699 healthy people to estimate consumption of and exposure to meat-cooking mutagens
The results showed RCC patients ate more red and white meat than the healthy individuals. The study also showed consumption of PhIP increased RCC risk by 54 percent, and nearly doubled the risk with consumption of MelQx. Additionally, people with variations in the gene ITPR2 — a gene already associated with cancer and obesity risk — are more vulnerable to the effects of PhIP
The researchers suggest not overcooking meat and using moderation with dietary choices, rather than cutting cooked meat out of diets altogether.
If you aren’t already cutting down/totally avoiding (or at least feeling guilty about eating) meat following the World Health Organization warning in October, a new study out this week may give you more reason to reconsider your dietary choices.
A paper published in this month’s issue of the journal Cancer finds that people who have diets high in meat may be at increased risk of developing kidney cancer. The research, which was funded by the National Institutes of Health as well as other grantees, involved collecting survey information about eating patterns and genetic data from 659 patients at the University of Texas MD Anderson Cancer Center who were newly diagnosed with renal cell carcinoma (RCC) and 699 healthy patients.
Here are five key points from the research
1. Individuals with kidney cancer consumed more red and white meat compared to those in the healthy control group.
2. The researchers theorize that the carcinogenic effect may come from the ingestion of meat-cooking mutagens that are created when meat is cooked at high temperatures or over an open flame — which includes barbecuing or pan-frying. Previous work has shown that these techniques result in the formation of two carcinogens: 2-amino-1-methyl-6-phenyl-imidazo(4,5-b) pyridine (PhIP) and amino-3,8-dimethylimidazo(4,5-f) quinoxaline (MeIQx). The study shows a 54 percent increased risk associated with PhIP intake and a nearly 200 percent increase with MeIQx intake.
3. Your genetics may make you more or less susceptible to the effects. Researchers found that patients with variations in the gene, ITPR2, which has previously been associated with kidney cancer, may be more vulnerable to ill effects to these mutagens.
4. The researchers aren’t suggesting that you should stop eating meat. They echoed recommendations from the American Cancer Society that people consume meats in moderation as part of a well-balanced diet that includes plenty of fruits and vegetables.
5. They did have specific recommendations about grilling or pan-fry meat, however. They say individuals should try to avoid charring it as much as possible.
Another study has shown people who eat more meat have a high risk of cancer. This time, it’s kidney cancer, researchers reported Monday.
And it’s not just people who eat red meat, as many other studies have shown. People who eat more so-called white meat, such as chicken, have the higher risk, too
Dr. Xifeng Wu and colleagues at The University of Texas MD Anderson Cancer Center in Houston studied 659 patients just diagnosed with kidney cancer and compared them to 699 similar people without cancer.
They wanted to break down not just the link, but to tease out the factors that might explain it. They looked at what kinds of meat people ate, how they cooked it, as well as people’s genetic makeup to see if certain genes made them more susceptible.
People who said they ate the most grilled meat — red meat and chicken alike — had a higher risk of kidney cancer, they reported in the journal Cancer. And those with two genetic mutations that already put people at higher risk of kidney cancer were most affected by the grilled meat risk.
People with kidney cancer also ate fewer fruits and vegetables than people who didn’t have it.
“Although previous studies have linked meat intake with an increased risk of (kidney cancer), to the best of our knowledge the underlying mechanism for this association remains unclear,” they wrote.
Cancer experts have long known that grilling or barbecuing meat can make it carcinogenic. Burning or charring meat creates cancer-causing substances.
In this case, the two culprits Wu’s team looked for were 2-amino-1-methyl-6-phenyl-imidazo(4,5-b) pyridine (PhIP for short ) and amino-3,8-dimethylimidazo(4,5-f) quinoxaline (MeIQx for short).
“Kidney cancer is among the 10 most common cancers in both men and women,” the American Cancer Society said. The group projects that more than 61,000 Americans will be diagnosed with kidney cancer this year and 14,000 will die of it.
“For reasons that are not totally clear, the rate of new kidney cancers has been rising since the 1990s, although this seems to have leveled off in the past few years,” the American Cancer Society added in a statement on its website.
“Part of this rise was probably due to the use of newer imaging tests such as CT scans, which picked up some cancers that might never have been found otherwise.”
Wu’s team also wonders whether an increase in eating meat might explain some of it.
The American/Western dietary pattern consists largely of red and processed meats, and the results of the current study suggest that the association between this dietary pattern and cancer may be in part explained by exposure to meat cooking mutagens,” they wrote.
Last month, the International Agency for Research on Cancer (IARC) released a controversial report that stated definitively that processed meats such as sausages and bacon cause cancer and that red meat probably does.
This study fits in with the studies that undergird the IARC’s pronouncement.
Outside experts said it will be important to find out just what the risk is and what people can do about it
“Once we have identified more genes we will likely be able to identify a subset of the population that is at particularly high risk to develop kidney cancer if they eat meat and processed meat,” said Dr. Ulrike Peters of the Fred Hutchinson Cancer Research Center in Seatlle.
“However, overall recommendations to limit intake of red and processed meat will remain for the entire population.”