Writing in the journal Circulation, scientists the Harvard School of Public Health (HSPH) sought to compare the health credentials of unprocessed and processed meat in a review of nearly 1,600 studies involving around 1.2m people.
Processed meat risks
The meta-analysis indicated that just 50g a day of processed meat, the equivalent of one hot dog, was associated with a 42 per cent higher risk of developing heart disease and a 19 per cent increase in risk of type 2 diabetes.
By contrast, the researchers found no link between eating unprocessed red meat like beef or pork and risk of heart disease and diabetes.
The scientists suggested that the difference between the results for unprocessed and processed meats could be explained by the high levels of salt and nitrate preservatives typically found in sausages, bacon and deli meats.
Salt and preservatives
Lead author Renata Micha said the two types of meat contain similar levels of saturated fat and cholesterol but processed meats in the US contain on average 4 times more sodium and 50 per cent more nitrate preservatives than unprocessed meats.
Micha said: “This suggests that differences in salt and preservatives, rather than fats, might explain the higher risk of heart disease and diabetes seen with processed meats, but not with unprocessed red meats.”
In light of their findings, the researchers suggested that future studies should look at processed and unprocessed meats separately to more accurately evaluate health effects. For example, a link has been established between total meat intake and colorectal cancer, but the Harvard scientists said this should be followed up be a separate evaluation only looking at unprocessed meats.
They also said more research is need needed to determine which factors, especially salt and other preservatives, are responsible for health issues in processed meats.
Red and Processed Meat Consumption and Risk of Incident Coronary Heart Disease, Stroke, and Diabetes Mellitus: A Systematic Review and Meta-Analysis
Authors: R. Micha, S. K. Wallace, D. Mozaffarian