Unprocessed red and processed meats and risk of coronary artery disease and type 2 diabetes--an updated review of the evidence

Abstract

Growing evidence suggests that effects of red meat consumption on coronary heart disease (CHD) and type 2 diabetes could vary depending on processing. We reviewed the evidence for effects of unprocessed (fresh/frozen) red and processed (using sodium/other preservatives) meat consumption on CHD and diabetes. In meta-analyses of prospective cohorts, higher risk of CHD is seen with processed meat consumption (RR per 50 g: 1.42, 95 %CI = 1.07-1.89), but a smaller increase or no risk is seen with unprocessed meat consumption. Differences in sodium content (~400 % higher in processed meat) appear to account for about two-thirds of this risk difference. In similar analyses, both unprocessed red and processed meat consumption are associated with incident diabetes, with higher risk per g of processed (RR per 50 g: 1.51, 95 %CI = 1.25-1.83) versus unprocessed (RR per 100 g: 1.19, 95 % CI = 1.04-1.37) meats. Contents of heme iron and dietary cholesterol may partly account for these associations. The overall findings suggest that neither unprocessed red nor processed meat consumption is beneficial for cardiometabolic health, and that clinical and public health guidance should especially prioritize reducing processed meat consumption.

Fig. 1

Risk of incident coronary heart disease (CHD) associated with each 100 g serving per day of unprocessed red meats (top; three cohort studies and one case-control study, 56,311 participants, and 769 events); and each 50 g serving per day of processed meats (bottom; four cohort studies and one case-control study, 614, 062 participants, and 21,308 events). The study by Sinha et al. (2009) assessed total cardiovascular (CHD plus stroke) mortality only. Solid diamonds and lines represent the study-specific relative risk (RR) and 95 % CI, respectively, derived from generalized least squares models for trend (GLST). The dashed line and open diamond represent the overall pooled RR and 95 % CI, respectively, as derived from both two-stage and one-stage GLST least squares for trend estimation. Reproduced with permission from Micha et al. (2010) [1••]

Fig. 2

Risk of incident type 2 diabetes associated with each 100 g serving per day of unprocessed red meats (top; nine cohort studies, 447,333 participants, and 28,206 events) and 50 g serving per day of processed meats (bottom; eight cohorts, 372,391 participants, and 26,234 events). Reproduced with permission from Pan et al. (2010) [18•]. Squares and lines are study-specific RRs and 95 % CI, respectively. Dashed line and open diamond are pooled estimate and 95 % CI, respectively