Replacing red meat with plant protein lowers risk for heart disease, Harvard study shows

Diets that replaced red meat with healthy plant proteins led to decreases in risk factors for cardiovascular disease (CVD), according to a new study from Harvard T.H. Chan School of Public Health and Purdue University, which was published in the journal Circulation.

The study included data from 36 randomized controlled trials involving 1,803 participants. The researchers compared people who ate diets with red meat with people who ate more of other types of foods, including chicken, fish, carbohydrates, or plant proteins such as legumes, soy, or nuts. Researchers looked at blood concentrations of cholesterol, triglycerides, lipoproteins, and blood pressure, all risk factors for CVD.

Researchers found that when diets with red meat were compared with all other types of diets combined, there were no significant differences in total cholesterol, lipoproteins, or blood pressure, although diets higher in red meat did lead to higher tryglyceride concentrations than the comparison diets. However, researchers found that diets higher in high-quality plant protein sources such as legumes, soy, and nuts resulted in lower levels of both total and low-density lipoprotein, “bad,” cholesterol compared to diets with red meat.

The results are consistent with long-term epidemiologic studies showing lower risks of heart attacks when nuts and other plant sources of protein are compared to red meat, the authors said. The findings also suggest that the inconsistencies found in prior studies regarding the effects of red meat on cardiovascular risk factors may be due, in part, to the composition of the comparison diet. They recommended that future studies take specific comparisons into account.

The authors also recommended adherence to healthy vegetarian and Mediterranean-style diets, both for their health benefits and to promote environmental sustainability.