Consuming < or > 0.5 Servings of Red Meat per Day Does Not Have a Negative Impact on Cardiovascular Disease Risk Factors; A Systematic Review and Meta‐analysis of Randomized Controlled Trials

Abstract

Epidemiological data historically link higher red meat intake and its nutritional components (i.e. saturated fats) to cardiovascular disease (CVD) end points but there are limited comprehensive analyses of randomized controlled trials investigating the influence of red meat consumption as a whole food on CVD risk factors. The purpose of this systematic review and meta‐analysis was to assess the effects of consuming < or > 0.5 servings (35 grams or 1.25 oz) of red meat per day on CVD risk factors including blood total cholesterol (TC), low‐density lipoprotein cholesterol (LDL), high‐density lipoprotein cholesterol (HDL), triglycerides (TG), TC:HDL ratio (TC:HDL), systolic (SBP)and diastolic blood pressures (DBP). We hypothesized based on the epidemiological data that consuming >0.5 servings of red meat per day would have a negative effect on these CVD risk factors. Two researchers independently screened 937 articles from PubMed, Cochrane, and Scopus databases and extracted data from 25 qualified randomized controlled trials. Red meat was inclusive of beef, pork, lamb, veal, and kangaroo; the median red meat intake of the >0.5 serving group was 140 g/day (2 servings or 5 oz; range: 50–500 g/day). 61% of studies identified consumption of lean red meats, 10% specified inclusion of processed meats, and 29% did not specify. 32% of articles used a “heart healthy” dietary pattern, 32% used a self‐selected diet, 12% used a weight loss diet, and 24% did not specify. A two way nested ANOVA mixed effect model procedure in SAS Version 9.4 (SAS Institute Inc, Cary, NC) was performed on the post‐intervention values of each dependent variable after adjusting for the baseline values of the dependent variable, age, sex, BMI, length of intervention and whether energy restriction was included in the protocol or not. Significance level was set at p<0.05. Although there was a decrease over time in TC, LDL, HDL, TG, TC:HDL, DBP but not SBP in both groups, the results showed no differences in post intervention values between the lower and higher red meat consuming groups for all dependent variables. As well, a random‐effects model meta‐analysis was conducted in STATA/SE 12 software (StataCorp LP., College Station, TX) using the metaan function on the change values of each dependent variable mentioned. These results showed no differences between the lower and higher red meat consuming groups in TC (weighted mean difference (WMD): 0.024 mmol/L; 95% CI=−0.045 to 0.094), LDL (WMD: 0.007 mmol/L; 95% CI=−0.059 to 0.072), HDL (WMD: −0.031 mmol/L; 95% CI=−0.074 to 0.012), TC:HDL (WMD: 0.117; 95% CI=−0.055 to 0.288), TG (WMD: −0.026 mmol/L; 95% CI=−0.089 to 0.037), SBP (WMD: 1.022 mm/Hg; 95% CI=−0.929 to 2.973), and DBP (WMD: −0.043 mm/Hg; 95% CI=−1.990 to 1.903). The results of this meta‐analysis of randomized controlled trials suggest that consuming >0.5 servings per day of red meat does not have a negative effect on cardiovascular disease risk factors compared to <0.5 servings of red meat per day when incorporated into a variety of dietary patterns.Support or Funding InformationPurdue Ingestive Behavior Research Center; NIH Training Grant #T32 DK076540