Meat Consumption and Increased Diabetes Risk: Building on the Current Evidence Base

Over the past few years, research has shown that consuming more processed red meat can increase an individual’s risk of type 2 diabetes. So, what is different about the latest research supporting this association?

Published in The Lancet Diabetes & Endocrinology, new findings once again revealed that higher consumption of unprocessed red meat and processed meat was associated with an increased risk of diabetes.¹ This meta-analysis involved data from 31 cohorts participating in the InterConnect project, with cohorts from the Americas (n = 12), the Eastern Mediterranean (n = 2), Europe (n = 9), Southeast Asia (n = 1), and the Western Pacific (n = 7).

The researchers identified more than 107,000 incident cases of type 2 diabetes over a median (IQR) follow-up of 10 (7-15) years and found that eating more red meat on a regular basis was yet again associated with an increased risk of incident diabetes. Specifically:

• Every 50 g of processed meat habitually consumed per day increased the risk by 15% (95% CI, 1.11-1.20; I²=59%)
• Every 100 g of unprocessed red meat consumed per day increased the risk by 10% (95% CI, 1.06-1.15; I²=61%)
• Every 100 g of poultry per day increased the risk by 8% (95% CI, 1.02-1.14; I²=68%)

For reference, 50 g of processed meat is the equivalent of 2 slices of ham or bacon, or 1 smoked sausage or hot dog. Processed red meat consumption has also been linked to an increase in colorectal cancer risk, with the risk going up by 18% for every 50 g eaten.²

50 g of processed meat is the equivalent of 1 hot dog | Image credit: Mediteraneo – stock.adobe.com

The authors cited prior findings that meat consumption can increase the risk of diabetes, but they also noted that existing evidence is largely based on studies of European and North American populations, which have heterogeneous analysis strategies and lack clear data on the relationship between poultry consumption and diabetes risk.¹

Why Does Meat Consumption Affect Diabetes Risk?

Meat consumption may increase the risk of type 2 diabetes through several mechanisms that negatively impact insulin sensitivity and pancreatic β-cell function. Red meat, high in saturated fatty acids and low in polyunsaturated fatty acids, has been associated with poorer insulin resistance, while diets rich in polyunsaturated fats have shown improvements in this area. The high protein content in meat, particularly animal proteins, may also be linked to a higher risk of diabetes.

Compounds formed during meat processing and cooking, such as trimethylamine N-oxide, nitrates, nitrites, and advanced glycation end products, can also contribute to oxidative stress, inflammation, and insulin resistance, further increasing diabetes risk. Long-term iron intake from meat is another factor that has been associated with a heightened risk of type 2 diabetes.

What This Adds to Prior Findings

“To our knowledge, we provide the most comprehensive evidence to date on the associations of unprocessed red meat and processed meat with type 2 diabetes, and our findings partly align with previous evidence,” the study authors said.

They noted their findings demonstrated weaker positive associations compared with previous research, which may have been influenced by publication bias. This review also included data from 18 unpublished cohorts, providing a broader perspective across 31 cohorts from 20 countries.

Additionally, while previous studies found no significant link between poultry intake and diabetes, the newest study included almost quadruple the number of cases and diverse populations, revealing a more nuanced but still uncertain association between poultry consumption and diabetes risk. The study also emphasized the potential confounding or mediating role of body mass index (BMI) in these associations.

“Notably, adjusting for baseline BMI provided interpretation under the energy-balanced condition, but could cause over-adjustment; BMI might be on the causal pathway and therefore be a mediator of the association between meat consumption and type 2 diabetes because of an association between meat intake and weight gain,” the authors said.

The authors also suggested that replacing processed meat with unprocessed red meat or poultry could lower diabetes risk compared with eating more processed meat.

Research published in 2023 showed that individuals who consume high amounts of red meat have a 62% higher risk of developing type 2 diabetes.³ The study, which analyzed data from over 200,000 participants across 3 major cohorts, found that both processed (51%) and unprocessed red meats (40%) were associated with an increased diabetes risk, with a stronger link for processed meat. The study also accounted for long-term dietary habits and BMI, which could mediate the relationship between red meat consumption and diabetes risk

Last year’s findings also supported dietary guidelines that advocate for reducing red meat intake, suggesting that replacing red meat with alternative protein sources like nuts, legumes, or dairy can significantly lower the risk of type 2 diabetes. However, the authors cautioned that the study's predominantly White population may limit the generalizability of these results, though similar trends were observed among Black participants.

Meanwhile, research from another year prior found that women who replaced processed red meat with fatty fish, unprocessed red meat, eggs, vegetables, or legumes had a reduced risk of developing hypertension and type 2 diabetes.⁴ The study, conducted using data from the E3N cohort, involved nearly 19 years of follow-up and identified significant associations between lower processed red meat consumption and decreased risks of these chronic conditions. While the findings support dietary modifications to reduce processed red meat intake, the study's limitations—including self-reported dietary data and the observational design—require further research to confirm these associations.

References

1. Li C, Bishop TRP, Imamura F, et al. Meat consumption and incident type 2 diabetes: an individual-participant federated meta-analysis of 1·97 million adults with 100 000 incident cases from 31 cohorts in 20 countries. Lancet Diabetes Endocrinol. 2024;12(9):619-630. doi:10.1016/S2213-8587(24)00179-7
2. Castillo M. Dr. Sanjay Gupta answers your questions on processed meats. CNN. October 27, 2015. Accessed September 3, 2024. https://www.cnn.com/2015/10/27/health/who-processed-meat-cancer-sanjay-gupta-fb/index.html
3. Klein HE. High red meat consumption linked to increased diabetes risk. AJMC^®. October 20, 2023. Accessed September 3, 2024. https://www.ajmc.com/view/high-red-meat-consumption-linked-to-increased-diabetes-risk
4. Bonavitacola J. Reduced processed red meat consumption may lower diabetes risk. AJMC. September 6, 2022. Accessed September 3, 2024. https://www.ajmc.com/view/reduced-processed-red-meat-consumption-may-lower-diabetes-risk