More research ties red meat to type 2 diabetes

Key takeaways:

• Total red meat consumption was associated with a 62% higher risk for developing type 2 diabetes.
• Substituting unprocessed red meat with legumes and nuts decreased type 2 diabetes risk by 41%.

Consumption of red meat was linked to an increased risk for type 2 diabetes, whereas replacing red meat with dairy, nuts and legumes reduced that risk, according to a recent study.

“Our findings strongly support dietary guidelines that recommend limiting the consumption of red meat, and this applies to both processed and unprocessed red meat,” Xiao Gu, PhD, a postdoctoral research fellow at Harvard T.H. Chan School of Public Health, said in a press release.

According to Gu and colleagues, previous research has associated type 2 diabetes risk with red meat, but the risk was reduced if red meat was replaced with other protein sources.

“However, in short-term randomized controlled trials, definitive effects of red meat intake on biomarkers of glycemic control or inflammation have not been seen,” they wrote in the American Journal of Clinical Nutrition.

So, the researchers evaluated risk associations of total, processed and unprocessed meat in a cohort of 216,695 participants from the Nurses’ Health Study (NHS), the NHS II and the Health Professionals Follow-up Study.

Red meat intake was assessed through food frequency questionnaires that were administered every 2 to 4 years over a period of 36 years, during which time 22,000 cases of type 2 diabetes were documented.

After the highest and lowest quintiles of each meat type were compared, the increased risk for developing type 2 diabetes was:

• 62% (HR = 1.62; 95% CI, 1.53-1.71) for total red meat;
• 51% (HR = 1.51; 95% CI, 1.44-1.58) for processed red meat; and
• 40% (HR = 1.4; 95% CI, 1.33-1.47) for unprocessed red meat.

Every additional serving of processed and unprocessed red meat increased the risk for diabetes by 46% (HR = 1.46; 95% CI, 1.4-1.53) and 24% (HR = 1.24; 95% CI, 1.2-1.29), respectively.

In contrast, the risk for type 2 diabetes after substituting red meat for one serving of nuts and legumes was:

• 30% lower (HR = 0.7; 95% CI, 0.66-0.74) for total red meat;
• 41% lower (HR = 0.59; 95% CI, 0.55-0.64) for processed red meat; and
• 29% lower (HR = 0.71; 95% CI, 0.67-0.75) for unprocessed red meat.

Substituting total red meat with one serving of dairy also reduced the risk for diabetes by 22% (HR = 0.78, 95% CI, 0.75-0.8).

Gu and colleagues said the associations became stronger after they calibrated dietary intakes to intakes that were assessed by weighed diet records.

For example, one serving of red meat before calibration was associated with a 28% greater risk for type 2 diabetes (HR = 1.28; 95% CI, 1.24-1.31), which rose to 47% (HR = 1.47; 95% CI, 1.37-1.58) after calibration.

The researchers acknowledged several limitations in their study, such as limited generalizability. The analysis also did not account for certain types of food preparation — for example, “hazardous chemicals such as advanced glycation end products and fatty acid isomers could be produced when deep frying or grilling fish and poultry and, therefore, diminish their health benefits when substituting red meats in diet,” they wrote.

Still, “given our findings and previous work by others, a limit of about one serving per week of red meat would be reasonable for people wishing to optimize their health and well-being,” study author Walter Willett, MD, PhD, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, said in the release.

References:

• Gu X, et al. Am J Clin Nutr. 2023;doi:10.1016/j.ajcnut.2023.08.021.
• Red meat consumption associated with increased type 2 diabetes risk. https://www.eurekalert.org/news-releases/1004904. Published Oct. 19, 2023. Accessed Oct. 19, 2023.