Red and processed meat consumption and risk of incident coronary heart disease, stroke, and diabetes mellitus: a systematic review and meta-analysis

Abstract

Background: Meat consumption is inconsistently associated with development of coronary heart disease (CHD), stroke, and diabetes mellitus, limiting quantitative recommendations for consumption levels. Effects of meat intake on these different outcomes, as well as of red versus processed meat, may also vary.

Methods and results: We performed a systematic review and meta-analysis of evidence for relationships of red (unprocessed), processed, and total meat consumption with incident CHD, stroke, and diabetes mellitus. We searched for any cohort study, case-control study, or randomized trial that assessed these exposures and outcomes in generally healthy adults. Of 1598 identified abstracts, 20 studies met inclusion criteria, including 17 prospective cohorts and 3 case-control studies. All data were abstracted independently in duplicate. Random-effects generalized least squares models for trend estimation were used to derive pooled dose-response estimates. The 20 studies included 1 218 380 individuals and 23 889 CHD, 2280 stroke, and 10 797 diabetes mellitus cases. Red meat intake was not associated with CHD (n=4 studies; relative risk per 100-g serving per day=1.00; 95% confidence interval, 0.81 to 1.23; P for heterogeneity=0.36) or diabetes mellitus (n=5; relative risk=1.16; 95% confidence interval, 0.92 to 1.46; P=0.25). Conversely, processed meat intake was associated with 42% higher risk of CHD (n=5; relative risk per 50-g serving per day=1.42; 95% confidence interval, 1.07 to 1.89; P=0.04) and 19% higher risk of diabetes mellitus (n=7; relative risk=1.19; 95% confidence interval, 1.11 to 1.27; P<0.001). Associations were intermediate for total meat intake. Consumption of red and processed meat were not associated with stroke, but only 3 studies evaluated these relationships.

Conclusions: Consumption of processed meats, but not red meats, is associated with higher incidence of CHD and diabetes mellitus. These results highlight the need for better understanding of potential mechanisms of effects and for particular focus on processed meats for dietary and policy recommendations.

Figure 1

Screening and selection process of studies of meat consumption and coronary heart disease, stroke, and diabetes risk.

Figure 2

Risk of incident coronary heart disease (CHD) associated with servings per day of red meat (top panel; 3 cohort studies and 1 case-control study, 56,311 participants, and 769 events), processed meat (mid panel; 4 cohort studies and 1 case-control study, 614,062 participants, and 21,308 events), and total meat (bottom panel; 4 cohort studies and 1 case-control, 635,558 participants, and 22,562 events). *Assessed total cardiovascular (coronary heart disease + stroke) mortality only.

Figure 3

Risk of incident diabetes associated with servings per day of red meat (top panel; 5 cohort studies, 298,982 participants, and 7,349 events), processed meat (mid panel; 7 cohort studies, 372,279 participants, and 10,782 events), and total meat (bottom panel; 3 cohort studies, 142,851 participants, and 5,923 events). *(EPIC)-Potsdam Study, includes most recent results.

Figure 4

Risk of incident stroke associated with servings per day of red meat (top panel; 2 cohort studies, 108,898 participants, and 1,700 events), processed meat (mid panel; 2 cohort studies, 108,898 participants, and 1,434 events), and total meat (bottom panel; 2 cohort studies, 115,500 participants, and 931 events).