There is a linear dose-response relationship between total meat, red meat, and processed meat intake and risk for type 2 diabetes (T2D), according to the results of a meta-analysis published in Diabetes and Metabolism.
Although there have been many studies showing a positive association between red meat and processed meat intake and T2D risk, more recent studies have had conflicting results, suggesting that the correlation remains controversial.
To quantitatively assess the associations of total meat, red meat, processed meat, poultry, and fish consumption with the risk for T2D, a total of 28 articles, including 25 cohort studies, were included in a meta-analysis. Overall, 11 of the studies were from the United States, 10 were from Europe, and 7 were from Asia. Total meat consumption was evaluated in 10 studies, and 17 studies evaluated red meat consumption, 17 evaluated processed meat consumption, 11 evaluated poultry consumption, and 20 evaluated fish consumption.
The analysis of data from a total of 386,496 individuals (22,482 with T2D) demonstrated a positive association between risk for T2D and total meat intake, which was stronger after exclusion of a Chinese study that contributed in part to significant heterogeneity (relative risk [RR] after exclusion, 1.39; 95% CI, 1.29-1.51; I2 =35.10%; P =.137). The RR for T2D was 1.36 (95% CI, 1.23-1.49) for each additional 100 g/d in total meat intake. In subgroup analyses, no such association was observed in studies conducted in Asia, and the association was weaker in studies that only considered women.
The analysis of data from a total of 663,144 individuals (49,086 with T2D) demonstrated a significant positive association between risk for T2D and red meat intake (RR, 1.24; 95% CI, 1.19-1.29; I2 =31.2%; P =.113) after exclusion of a study that significantly affected heterogeneity. The RR for T2D was 1.31 (95% CI, 1.19-1.45) for each additional 100 g/d in red meat intake. In subgroup analyses, no significant association was observed in studies conducted in Asia.
A significant association between risk for T2D and processed meat consumption was also demonstrated (RR, 1.27; 95% CI, 1.20-1.35, I2 =54.70%; P =.005). The RR for T2D was 1.46 (95% CI, 1.26-1.69) for each additional 50 g/d in processed meat intake. When 9 studies were added to account for potential publishing bias, a nonlinear dose-response relationship between processed meat intake and T2D was observed (P =.004), with risk increasing by 30% for every additional 30 g/d of intake. In subgroup analyses, no significant association was observed in studies conducted in Asia.
No significant association was found between poultry or fish intake and risk for T2D.
Overall, the results of this meta-analysis demonstrated a positive association between T2D and total meat consumption, red meat consumption, and processed meat consumption. Such positive associations could not be confirmed in Asian studies, potentially because “the dietary trend towards greater meat consumption has been more recent [in these populations] compared with the US and Europe,” researchers noted. The specific types of meat included in each category also may have varied by region. The mechanism by which meat intake affects T2D risk remains unknown.
Limitations to this study included the potential publication bias in studies that demonstrated an association between risk for T2D and processed meat intake, as shown by Egger’s linear regression test (P =.002 in the processed meat analyses), as well as the exclusion of information regarding changes to meat intake during follow-up.
Future studies verifying these conclusions through additional observational studies and interventional trials are warranted.
Yang X, Li Y, Wang C, et al. Meat and fish intake and type 2 diabetes: dose-response meta-analysis of prospective cohort studies [published online April 14, 2020]. Diabetes Metab. doi:10.1016/j.diabet.2020.03.004