Is halving red and processed meat intake heart healthy?

Meat is a common source^[1] of protein, fat, and micronutrients in many diets worldwide. However, according to the results from observational research^[2], the consumption of red meat (e.g., beef, pork, veal, and lamb) and processed meat (i.e., meat that has been smoked, cured, salted, and/or had chemical preservatives added) has been associated with an increased risk of developing a range of chronic diseases, including cardiovascular disease (CVD).

While the results from most observational studies report a link between red and processed meat (RPM) and CVD risk, findings from randomized controlled trials have been less consistent, and the results from recent meta-analyses^[3][4][5] of intervention studies have questioned the notion that red and processed meats contribute significantly to the development of CVD. Nevertheless, people are generally still encouraged^[6] to limit red and processed meat intake.

There may be a number of reasons for the inconsistent results between studies. For example, in observational research, confounding variables, such as bodyweight, smoking, and physical activity, may explain the observed association between RPM and CVD risk. While it’s important to acknowledge that even when researchers attempt to control for these variables, it’s always possible that there is some residual confounding. In intervention trials, differences in study design, such as in the characteristics of the participants, the length of the intervention period, and the statistical methods, can affect the results. Furthermore, the inconsistencies regarding the effects of RPM on CVD risk factors may also be partly attributable to the composition of the comparison diets. Since adding or subtracting any food source from the diet is usually compensated by a similar caloric substitution (assuming bodyweight is maintained), differences between trials in the foods used to replace RPM can affect the outcomes.

With the above in mind, and considering that CVD still accounts for around one‐third^[7] of all deaths in people older than 35, it’s obvious that there is a need for more interventional research on the links between RPM intake and CVD risk. The study under review aimed to add to the relevant body of literature by examining the effects of a 50% reduction in RPM in habitual RPM consumers through the consumption of reduced meat and meat-free meals on changes in the blood lipid profile and other CVD risk factors.

According to observational research, the consumption of red and processed meat is associated with a higher risk of cardiovascular disease. However, the results from interventional studies have questioned this notion. The inconsistent results between studies may be attributable to a number of reasons, and highlight the need for more relevant interventional research. The study under review aimed to add to the body of literature by examining the effects of a 50% reduction in RPM through the consumption of reduced meat and meat-free meals on changes in classic CVD risk markers.