Eating processed meats like hot dogs, bacon and deli meat could increase your risk for heart disease and diabetes compared to eating unprocessed red meats like beef and lamb, according to a new study.
But many experts were not convinced that the findings tipped the scale in favor of red meat.
The study published today in Circulation looked at 20 studies involving more than 1 million participants from 10 different countries. Researchers found that eating as little as 2 ounces of processed meat per day -- a few strips of bacon, a hot dog or smoked sausage -- increased the risk of heart disease by 42 percent and the risk of diabetes by 19 percent.
However, the culmination of studies examined found eating unprocessed red meat like steak, burgers and roasts did not seem to carry the same risks.
The study suggested that the increased risk of heart disease and diabetes with processed meat may be related to the higher salt and preservatives that are normally found in processed meats.
While research found that both red meat and processed meats contained similar amounts of saturated fat and cholesterol -- both a contributing factor for heart disease and stroke -- processed meats had on average four times higher levels of salt and other preservatives, according to lead author of the study Renata Micha, research fellow in the department of epidemiology at Harvard School of Public Health.
On average a 50 gram serving of red meat contains about 127 mg of sodium, while the same serving amount of processed meat contains about 575 mg of sodium, according to data based on a 2005-2006 United States National Health and Nutrition Examination survey.
Although the research findings took harder aim at processed meat, many said the study is not enough to suggest that people should stop eating processed meat, or to exonerate red meat from health risks similar to those processed meat, including heart disease and diabetes.
According to Dr. Steven Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic, the study did not take into account a person's overall lifestyle as a contributing factor for heart disease.
"Meat eaters also have many other unmeasured habits that may promote heart disease or diabetes," Nissen said. "Therefore, we don't know if the problem is meat consumption or associated health behaviors."
In fact, Janet Riley, senior vice president of the American Meat Institute stood up for processed meats and said the data was inconclusive.
"I'm a little concerned that consumers are getting another case of nutrition whiplash," Riley said. "Americans are starting to tune out because one week red wine's good for them, the next week, not so much. One week it's oat bran, the next it's maybe not. Very confusing to consumers."
Current USDA guidelines suggest eating meat in moderation, and according to Joan Salge Blake, a registered dietician and clinical associate professor at Boston University's Sargent College of Health and Rehabilitation Sciences, Americans should limit their intake of lean meats, fish, or poultry to 6 to 7 ounces a day.
"This way you have more room on your plates for vegetables that we know are heart healthy," Blake said.
But, many experts said, people do not need to eliminate processed meat completely from their diet. Instead, some experts suggest being cautious about the amount of processed meat you may be eating. In fact, experts said, although the study is not definitive, it raised important questions that consumers need to know.
"The study doesn't suggest that people should panic if they had a piece of processed meat for lunch or cut it out of their diet completely, but as people are making choices [it] may be better to move away a little bit from the processed meats," said Harlan Krumholz, professor of medicine and epidemiology at Yale University School of Medicine.
One serving per week or less of processed meat, equivalent to perhaps one hot dog or two slices of deli meat, would be relatively low risk, Micha said.
Although Krumholz agreed that both processed and unprocessed foods hold their fair share of health risks, he said moderation of both processed and unprocessed meats contributes to an overall healthy diet.
"It's about portion size and about eating sensibly," Krumholz said. "If people use prudence in looking at their meals, they're going to do fine."
Average Nutritional and Preservative Contents in Red Meats* (Examples: Steak, Hamburger, Pork Chops and Lamb) (per 50g)
SODIUM: 127.1 mg
TOTAL FAT: 7.7 g
SATURATED FAT: 2.9 g
PROTEIN: 13.5 g
NITRATES: 2.9 mg
Average Nutritional and Preservative Contents in Processed Meats* (Examples: Bacon, Sausage, Packaged Ham and Hot Dogs)
SODIUM: 575.8 mg
TOTAL FAT: 12.3 g
SATURATED FAT: 4.4 g
PROTEIN: 8.8 g
NITRATES: 3.0 mg
CHOLESTEROL: 28.3 mg
*Data based on a 2005-2006 United States National Health and Nutrition Examination Survey