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By Kathleen Doheny
WebMD Health News
Reviewed by Elizabeth Klodas, MD, FACC
March 23, 2009 -- Men and women who eat higher amounts of red meat and processed meat have a higher risk of dying from cancer, heart disease , and other causes compared to those who eat less, according to a new study.
Those in the study who ate the most red meat took in about 4.5 ounces a day -- the equivalent of a small steak.
"We found the consumption of red and processed meat is associated with a modest increase in overall mortality, as well as cancer and cardiovascular mortality in both men and women," says study researcher Rashmi Sinha, PhD, a senior investigator at the National Cancer Institute.
The study, supported by the National Cancer Institute, is published this week in the Archives of Internal Medicine. The author of an accompanying editorial says he views the risks found in the study as more than "modest."
Cutting down on red meat and processed meat would result in a "meaningful saving of lives," Barry Popkin, PhD, tells WebMD. Popkin is The Carla Smith Chamblee Distinguished Professor of Global Nutrition at the University of North Carolina School of Public Health, Chapel Hill. In a note accompanying his editorial, he states that he is not a vegetarian and has no financial conflict of interest related to food products affecting health.
Red Meat and Processed Meat Study
The recent study is believed to be the largest study to date looking at the links between red and processed meat and their effect on the risk of death from cancer, heart disease, and other causes, Sinha tells WebMD.
Her team evaluated more than 500,000 men and women who participated in the National Institutes of Health-AARP Diet and Health Study. Participants were between the ages of 50 and 71 when the study began in 1995, and all provided detailed information about their food intake.
The researchers followed them for 10 years, using the Social Security Administration's databases to track causes of death. During the follow-up period, 47,976 men and 23,276 women died.
Then the researchers evaluated dietary habits. "We divided people into five categories," Sinha tells WebMD, according to how much red meat and processed meat was eaten on a daily basis.
White meat included turkey, fish, chicken, chicken mixtures, and other meats.
Meat Intakes: High vs. Low
What was considered a high intake and what was low?
- For red meat, those in the highest intake group ate a median amount of 4.5 ounces a day (half ate more, half ate less), based on an average 2,000-calorie a day diet. Those in the lowest intake group ate a little over a half-ounce a day.
- For processed meat, those in the highest intake group about 1.5 ounces a day (about 2 slices of deli turkey), compared to just 0.11 ounces for those in the lowest intake group.
Those who ate the most red meat as well as the most processed meat had a higher overall risk of dying during the study period as well as a higher risk of dying from cancer and heart disease compared to those who ate the least of both.
For instance, men in the group with the highest intake of red meat had a 31% higher overall risk of dying during the study period than did those in the lowest intake red meat group. And women with the highest intake of red meat had a 50% higher risk of dying due to heart disease. Or put another way, Sinha says that 11% of all deaths in men and 16% of deaths in women could have been prevented if participants cut their red meat consumption to that eaten by the lowest intake group. Heart disease deaths could have been decreased by 11% in men and 21% in women by limiting red meat intake to the amount eaten by the lowest intake group.
For processed meat, the highest intakes were associated with a 16% overall increased risk of dying in men and 25% increased risk in women.
Cancer risk was about 20% higher in those who ate the most red meat, and 10% higher in those who ate the most processed meats.
In contrast, the intake of white meat was often protective, with those eating the most having a slightly lower risk for overall and cancer deaths.
Exactly why red meat and processed meat are associated with increased risks of cancer, heart disease and other deaths isn't known for sure, Sinha says. But the leading explanations, she says, include:
- The meats are a source of carcinogens formed during cooking.
- The iron in red meat may increase oxidative cell damage, leading to health problems.
- The saturated fat found in meat has been linked with breast and colorectal cancer.
On its web site, the National Cattlemen's Beef Association notes that beef offers protein and other essential nutrients.
It offers information on lean cuts of beef to reduce the amount of saturated fat eaten.
In a statement, Shalene McNeill, PhD, RD, executive director of human nutrition research for the National Cattlemen's Beef Association, says: “As is often the case with epidemiological research on this subject, it is hard to draw substantial conclusions about any one food.” She said the study was complicated by the fact that participants had unhealthy behaviors such as smoking and lack of exercise.
There is a place in the diet for lean meats, she says.
Advice on Meat in the Diet
Sinha tells WebMD that she cannot make recommendations based on the study but says that the results complement the advice of such organizations as the American Institute for Cancer Research.
To reduce cancer risk, the web site of the American Institute for Cancer Research recommends eating no more than 18 ounces of red meat (cooked weight) per week (or about 2.5 ounces a day.) It recommends avoiding processed meat, noting that research suggests that cancer risk starts to increase with any amount.
Popkin agrees that processed meats are worse than red meats from a health point of view. He says the new study results suggest consumers can reduce their risk of dying from cancer, heart disease, or other problems by curtailing their intake of red and processed meats.
But he's not saying it's crucial to give up meat entirely. "I think what this is saying is, 'You don't have to be a vegan. You don't have to be a vegetarian.' But you really need to cut out the sausage and the pepperoni and the baloney, all those processed meats, or have them very little. You also need to be careful and cut down your red meat intake. Have it [only] a couple times a week."
Rashmi Sinha, PhD, senior investigator, nutritional epidemiology branch, division of cancer epidemiology and genetics, National Cancer Institute of the National Institutes of Health, Rockville, Md.
Barry Popkin, PhD, The Carla Smith Chamblee Distinguished Professor of Global Nutrition, School of Public Health, University of North Carolina, Chapel Hill.
Sinha, R. Archives of Internal Medicine, March 23, 2009; vol 169: pp 562-571.
Popkin, B. Archives of Internal Medicine, March 23, 2009; vol 169: pp 543-545.
American Institute for Cancer Research web site.
National Cattlemen's Beef Association web site.
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