Last year, we reported on research suggesting an association between processed meat and Type 2 diabetes. Now, a large meta-analysis (in which statistics from several studies are combined and examined) from the Harvard School of Public Health has established a link between the consumption of red meat, and processed meat in particular, and the risk of developing Type 2 diabetes. Type 2 affects an estimated 26 million people in the United States; another 79 million have prediabetes and are at high risk of developing Type 2.
The researchers analyzed questionnaire responses from over 200,000 health-care providers in the Nurses’ Health Studies and Health Professionals Follow-Up Study. They also combined their data with that of other published studies for a total of 442,101 participants, 28,228 of whom developed Type 2 diabetes during the course of the studies.
After adjusting for age, body-mass index, weight, physical activity level, smoking, family history of diabetes, and various other lifestyle and dietary factors, the study authors discovered that consuming 100 grams of red meat (roughly the size of a deck of cards) on a daily basis was associated with a 19% increased risk of Type 2. Eating 50 grams of processed meat (equivalent to about two slices of bacon or a single hot dog) was associated with a 51% increased risk.
The researchers suspect that the sodium and nitrites (chemicals commonly used to preserve food) in the processed meats and the amount of heme iron in the unprocessed meats might be the culprits behind the increased diabetes risk associated with these foods. (Having too much iron in the body is a risk factor for diabetes.) But according to Frank B. Hu, MD, MPH, PhD, senior study author, “there are probably other factors in these meats that contribute to diabetes.”
Substituting other protein sources for the meat servings was associated with a decreased risk of Type 2 diabetes. For instance, replacing a daily serving of red meat with a serving of nuts was linked with a 21% lower risk of Type 2; replacing the meat with a serving of low-fat dairy was linked with a 17% lower risk; and replacing the meat with a serving of whole grains was linked with a 23% lower risk of Type 2. Accordingly, the researchers suggest that consumption of processed red meat should be kept to a minimum and unprocessed red meat should be reduced. They advise replacing the meat with healthful food choices such as fish, beans, low-fat dairy products, nuts, or whole grains.
Hu noted that “The results from this study have huge public health implications given the rising Type 2 diabetes epidemic and increasing consumption of red meats worldwide. The good news is that such troubling risk factors can be offset by swapping red meat for a healthier protein.”
Previous research has shown an increased risk of Type 2 (as well as heart disease and cancer) associated with the consumption of red meat, but this is the largest study, in terms of sample size and years of follow-up, to demonstrate this risk. The research also offers clarification on the link between processed meats and diabetes risk, which had been ambiguous due to conflicting data from previous studies.
To learn more about the research, read the articles “Red Meat Linked to Increased Risk of Type 2 Diabetes” or “Red, Processed Meat Linked to Higher Type 2 Diabetes Risk” or see the study’s abstract in the American Journal of Clinical Nutrition.