About the Study | How Does This Affect You?

The development of type 2 diabetes and heart disease has been on the rise. These conditions increase the need for medical care and medicine and can decrease life expectancy. There are many factors that can contribute to the development of these diseases, such as dietary choices. Your overall diet may contribute to your risk by leading to excess weight or because it is rich in certain foods. For example, a diet high in sugar or saturated fats and low in fiber, fruits, and vegetables is more likely to lead to health problems. Meats have often been associated with increased risk of diseases, but studies have recently suggested that it may be specific types of meat that actually increase risk.

Investigators from Harvard School of Public Health examined several past studies to look for any trends between the development of heart disease and diabetes and particular meat consumption. The study, published in Circulation, found that processed meat was associated with diabetes and coronary heart disease.

About the Study

The systematic review included 20 previous observational studies with a total of 1,218,380 adults. The studies tracked how much red and processed meats (eg, bacon, sausage, hot dogs, pepperoni, ham, packaged lunch meats) participants consumed, as well as which participants developed coronary heart disease and diabetes. In total, the studies reported:

  • 23,889 patients developed coronary heart disease
  • 10,797 patients developed diabetes
When investigators compared the diet of the patients that developed these diseases with the diets of those that did not develop the diseases, they found:
  • Red meat intake (average 3.5 ounces per day) was not associated with the development of coronary heart disease or diabetes
  • Processed meat (average 1.8 ounces daily -1-2 slices deli meat or 1 hot dog daily) was associated with:
    • 42% higher risk of coronary heart disease
    • 19% higher risk of diabetes
  • A daily total of 3.5 ounces of processed and red meats:
    • Not associated with increased risk of heart disease
    • Associated with a 12% higher risk for diabetes

How Does This Affect You?

This study was based on observational studies, which means a cause and effect relationship cannot be determined. The studies can simply suggest that a link may or may not exist. A systematic review increases the power of the studies by bringing together smaller studies and showing common patterns. A review with over a million people certainly carries some weight. However, combining several studies also introduces some statistical limits that could overestimate the effect. To confirm the effects, randomized trials would need to be done.

Processed meats have significantly higher levels of sodium and nitrates than unprocessed meats. These factors are thought to increase risk of these diseases, but further studies will need to be done to confirm. Any food requires a balanced approach. Processed meats should be limited and not included everyday, but they do not necessarily need to be completely eliminated from your diet. Instead of processed meat, lean varieties of red meat may be a better option. They have a lower amount of fat and salt and are great sources of protein, iron, zinc, vitamins B6 and 12, and niacin. When choosing your meat, look for options that decrease the negative aspects like sodium and saturated fats—that way you can have your steak and eat it too!