Red meat linked to esophageal, stomach cancer risks By Amy Norton
NEW YORK ' Fri Nov 5, 2010 11:34am EDT
NEW YORK (Reuters Health) - Red-meat lovers may have a greater likelihood of developing certain cancers of the throat and stomach than people who limit their intake of steaks and hamburgers, a new study suggests.
Researchers found that among nearly 500,000 older U.S. adults followed for a decade, only a small number developed cancers of the esophagus or stomach. However, the risks were relatively greater among those who ate a lot of red meat, or certain compounds generated from cooking meat.
Overall, study participants in the top 20 percent for red-meat intake were 79 percent more likely than those in the bottom 20 percent to develop esophageal squamous cell carcinoma -- a cancer that arises in the lining of the upper part of the esophagus.
Meanwhile, the risk of a type of cancer in the upper portion of the stomach near the esophagus (gastric cardia) was elevated among men and women with the highest estimated intake of one form of heterocyclic amine (HCA). HCAs are compounds that form when meat is cooked using high-temperature methods, such as grilling over an open flame; they have been found to cause cancer in lab animals.
The findings, reported in the American Journal of Gastroenterology, do not prove that red meat promotes the two cancers, the researchers emphasize.
But the results add to what has been an uncertain body of evidence on the link between red meat and esophageal and stomach cancers.
A 2007 research review by the World Cancer Research Fund and American Institute for Cancer Research, both non-profit groups, concluded that red and processed meats were associated with a "limited suggestive increased risk" of esophageal cancer.
The report also said there was a similar level of evidence for a link between processed meats and stomach cancer, and insufficient data on whether red meat intake is connected to the cancer at all.
However, most of the studies considered in the report were so-called case-control studies, where researchers ask patients with a given disease about their past lifestyle habits and other health factors, then compare them to a group of healthy individuals.
That type of study design can offer only limited evidence about whether a particular exposure -- like red meat in the diet -- is related to a disease risk, explained Dr. Amanda J. Cross, a researcher at the U.S. National Cancer Institute who led the new study.
Studies with prospective designs, which follow initially healthy people over time, provide stronger evidence.
In addition, most earlier research did not look at meat intake and different subtypes of esophageal and stomach cancers. That is important, Cross told Reuters Health, because the different subtypes seem to have different risk factors.
So for their study, Cross and her colleagues prospectively followed 494,979 U.S. adults ages 50 to 71 over roughly 10 years. At the outset, participants completed detailed questionnaires on their diets -- including the methods they typically used for cooking meat, and the usual level of "doneness" they preferred -- as well as other lifestyle factors.
Over the next decade, 215 study participants developed esophageal squamous cell carcinoma; that included 28 cases among the bottom 20 percent for red-meat intake, and 69 cases in the top 20 percent.
Another 454 men and women were diagnosed with gastric cardia cancer. There were 57 cases among participants with the lowest red-meat intake, and 113 in the group with the highest intake.