Red Meat, Comparison Diets and CVD
Posted:
2019-04-16
A new meta-analysis of random control studies looked at the effects of red meat consumption and risk factors for cardiovascular disease (blood lipids, 
apolipoproteins, blood pressure) (1). The meta-analysis involved 1,803 participants from 36 RCTs that compared red meat diets with diets that replaced red meat with a variety of foods. The study found that the results depended on the composition of the comparison diet: there were improvements in blood lipids when red meat was substituted with high quality plant protein sources but not when replaced with low quality carbohydrates. The senior author of the study, Meir Stampfer, stated: “Asking 'Is red meat good or bad?' is useless,"…. "It has to be 'Compared to what?' If you replace burgers with cookies or fries, you don't get healthier. But if you replace red meat with healthy plant protein sources, like nuts and beans, you get a health benefit" (1).
PEN Team Comment:
This study combined the results from 36 randomized controlled trials. Randomized controlled trials can give more certainty of the findings. If the trials were well-designed and conducted, the intervention and control groups should be similar, providing confidence that any differences in outcome were due to the intervention compared to the comparison group. The confidence intervals from the individual studies (seen as the horizontal lines for each study in the Figures) were wide, indicating variability in the results and/or small sample sizes.
In addition, this study identified one of the difficulties of nutrition trials: “Inconsistencies regarding the effects of red meat on cardiovascular disease risk factors are attributable, in part, to the composition of the comparison diet” (2).
References
- ScienceDaily. Substituting healthy plant proteins for red meat lowers risk for heart disease. 2019 Apr 9. Available from: https://www.sciencedaily.com/releases/2019/04/190409141808.htm
- Guasch-Ferre M, Satija A, Blondin SA, Janiszewski M, Emlen E, O’Connor LE, et al. Meta-analysis of randomized controlled trials of red meat consumption in comparison with various comparison diets or cardiovascular risk factors. Circulation. 2019 Apr 9;139(15):1828-45. doi:10.1161/CIRCULATIONAHA.118.035225. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/30958719