High Meat Consumption Linked to Heightened Cancer Risk

High Meat Consumption Linked to Heightened Cancer Risk
TUESDAY, Dec. 11 (HealthDay News) -- A quarter-pound hamburger or asmall pork chop eaten daily could put you at increased risk for a varietyof cancers, U.S. government health researchers report.
The more red meat and processed meat you eat, the greater your risk,the researchers from the National Cancer Institute concluded.
"Red and processed meats have been associated with an elevated riskwith colorectal cancer. We investigated whether this association was alsoevident for cancers at other anatomic sites," explained lead author AmandaCross, an epidemiologist at the National Cancer Institute (NCI). "This isthe largest study to look at the effect of red and processed meat onmultiple cancer sites, including rarer cancers, such as laryngeal andliver cancer."
For the study, red meats included beef, pork and lamb. Processed meatsincluded bacon, red-meat sausage, poultry sausage, luncheon meats, coldcuts, ham, regular hot dogs and low-fat hot dogs.
Cross and her team from the National Institutes of Health and the AARPanalyzed health data from 500,000 people aged 50 to 71 who participated inthe National Institutes of Health-AARP Diet and Health Study beginning in1995-1996. They followed participants for about eight years, during whichtime they recorded 53,396 cases of cancer. In addition to meat consumptionhabits, the participants detailed other lifestyle choices such as smokingand exercise.
The team then grouped people into five categories according to theirlevel of meat consumption.
"The highest category of red meat was those consuming the equivalentof a quarter pound hamburger or a small steak or a pork chop per day,"said Cross, who added that the lowest category was equivalent toapproximately three thin slices of ham or less per day.
For processed meat, the lowest category of consumption equated to nomore than one slice of bacon a day, while the highest consumptioncategory covered four slices a day.
The median consumption of red meat was 31.4 grams per 1,000 calories,which is about two and a half ounces of red meat a day for a personconsuming the average 2,000-calorie diet.
Overall, the researchers found elevated risks for colorectal and lungcancer with high consumption of both meat types along with borderlinehigher risks for advanced prostate cancer. High red meat intake was alsoassociated with increased risk of esophageal and liver and a borderlineincreased risk for laryngeal cancer. And high processed meat consumptionalso was associated with borderline increased risk for bladder cancer andmyeloma, a kind of bone cancer.
In addition, both red meat and processed meat consumption wereassociated with increased pancreatic cancer risk in men, but notwomen.
And the research team noted an unexpected effect of red meat onendometrial cancer: the more red meat women consumed, the less likelythey were to suffer from endometrial cancer.
"Our findings for colorectal cancer are consistent with therecommendations from the recently published World Cancer Research Fund andAmerican Institute for Cancer Research to limit consumption of red meats,such as beef, pork and lamb," said Cross. "Our study also suggests thatindividuals consuming high quantities of red meat may be at an elevatedrisk for esophageal, liver and lung cancer."
There are several possible routes by which red and processed meats maycontribute to cancer, the NCI researchers said. Meats are a source ofsaturated fat and iron, both of which have been linked to cancer, and alsothe source of several compounds that are known to affect cell development,they added.
Cooking at high temperatures might also contribute to cancer risk,Cross added.
"Heterocyclic amines and polycyclic aromatic hydrocarbons are formedwhen meats are cooked well-done by high temperature cooking methods, suchas barbecuing," she said.
The study, published in the December 2007 issue of the online journalPLoS Medicine, brought a mixed response from experts in thefield.
"This adds to the body of knowledge that supports recommendations thatto reduce the risk of colon cancer, you should reduce your consumption ofred and processed meats," said Colleen Doyle, director of nutrition andphysical activity for the American Cancer Society. "It also adds to thesmaller amount of research tying red and processed meats to other types ofcancer risk. The American Cancer Society recommends reducing red andprocessed meat consumption to reduce the risk of prostate cancer."
"We really see this study that it further illustrates the complexityand challenges of understanding research related to diet and cancer. Theyalso could have said red meat is protective of endometrial cancer. Thechallenges of looking at diet and cancer are just vast," said Mary K.Young, vice president for nutrition with the National Cattlemen's BeefAssociation. She noted that the researchers did not ask how food wasprepared, which she said could have affected the health outcomes.
Doyle and Young, both dietitians, agreed that diet can play acritical role in health.
"One of the most important things people can do to lower their risk ofchronic disease, including cancer, is maintain a healthy weight," addedYoung, who recommended that people follow national dietary guidelines,watch their serving sizes and stay physically active.
People worrying about cancer and diet should take a balanced approach,said Doyle. " No one food is going to put our cancer risk over the top.If you are someone who eats steak or pork or lamb or salami or hot dogs,etc., on a regular basis and/or in large portion sizes, I would probablysuggest you look for healthier protein sources to include in your diet,"she added. The American Cancer Society recommends that people eat lots offruits, vegetables and whole grains with some lean proteins to preventcancer.
Research released last summer in the e Journal of the NationalCancer Institute suggested that choline, found in many red meat anddairy products, may contribute to the growth of polyps that lead to coloncancer.
And another study, released in the Aug. 17 Journal of the AmericanMedical Association, showed that colon cancer patients who eat a dietrich in fruits, vegetables, poultry and fish can significantly lower therisk of their cancer returning. In contrast, those patients whoseself-reported diet included high intakes of meat, fat, refined grains anddessert were more than three times more likely to see their colon cancerreturn.
"If I were a cancer survivor," Doyle said, the new research "would makeme stand up and take notice."