Washington: Eating processed meat such as sausages raises the likelihood of heart disease, while red meat does not seem to be as harmful, researchers from the Harvard School of Public Health (HSPH) have found.
The study found that eating processed meat was associated with a 42 percent higher risk of heart disease and a 19 percent higher risk of type 2 diabetes.
In contrast, the researchers did not find any higher risk of heart disease or diabetes among individuals eating unprocessed red meat, such as from beef, pork, or lamb.
"Although most dietary guidelines recommend reducing meat consumption, prior individual studies have shown mixed results for relationships between meat consumption and cardiovascular diseases and diabetes," said Renata Micha, a research fellow in the department of epidemiology at HSPH and lead author of the study. "Most prior studies also did not separately consider the health effects of eating unprocessed red versus processed meats."
The study appears online May 17, 2010, on the website of the journal Circulation.
The researchers, led by Renata Micha, a research fellow in the department of epidemiology, and HSPH colleagues Dariush Mozaffarian, assistant professor in the department of epidemiology and Sarah Wallace, junior research fellow in the department of epidemiology, systematically reviewed nearly 1,600 studies. Twenty relevant studies were identified, which included a total of 1,218,380 individuals from 10 countries on four continents (United States, Europe, Australia, and Asia).
The researchers defined unprocessed red meat as any unprocessed meat from beef, lamb or pork, excluding poultry.
Processed meat was defined as any meat preserved by smoking, curing or salting, or with the addition of chemical preservatives; examples include bacon, salami, sausages, hot dogs or processed deli or luncheon meats. Vegetable or seafood protein sources were not evaluated in these studies.
The results showed that, on average, each 50 gram (1.8 oz) daily serving of processed meat (about 1-2 slices of deli meats or 1 hot dog) was associated with a 42 percent higher risk of developing heart disease and a 19 percent higher risk of developing diabetes. In contrast, eating unprocessed red meat was not associated with risk of developing heart disease or diabetes. Too few studies evaluated the relationship between eating meat and risk of stroke to enable the researchers to draw any conclusions.
"Although cause-and-effect cannot be proven by these types of long-term observational studies, all of these studies adjusted for other risk factors, which may have been different between people who were eating more versus less meats," said Mozaffarian. "Also, the lifestyle factors associated with eating unprocessed red meats and processed meats were similar, but only processed meats were linked to higher risk."