|Blood pressure||Diets rich in plant-based foods, particularly vegetarian and vegan diets, reduce systolic and diastolic blood pressure, presumably due, in part, to their high potassium content and their tendency to reduce blood viscosity and improve endothelial function (33,157,158). The DASH (Dietary Approaches to Stop Hypertension) study, which was in large part inspired by the blood pressure–lowering effect of vegetarian diets, was successful in lowering blood pressure (159), and was associated with favorable changes in diastolic and arterial function among individuals with heart failure with preserved ejection fraction (47).|
|Body weight||Diets rich in plant-based foods are consistently associated with reduced body weight in observational studies and clinical trials, apparently due to their low energy density and tendency to increase postprandial energy expenditure. Those following entirely plant-based (vegan) diets have demonstrably healthier body weights, on average, compared with other groups (31,42,160).|
|Lipid control||Elevated LDL cholesterol (161) concentrations and atherosclerotic cardiovascular disease (162) contribute to endothelial dysfunction, which is associated with systolic and diastolic heart failure (163). Because most plants are extremely low in saturated fat and devoid of cholesterol, and many are rich in soluble fiber or other lipid-lowering ingredients, plant-based diets improve plasma lipid concentrations (32). Vegetarian diets may also render LDL cholesterol more resistant to oxidation (164).|
|Glycemic control||Diabetes and insulin resistance are associated with altered energy metabolism, adverse cardiac remodeling, and incident heart failure (165,166). Vegan diets are associated with a particularly low prevalence of type 2 diabetes (167) and improve glucose metabolism in individuals with diabetes (42). Moreover, a Mediterranean diet versus control has been associated with lower incident diabetes (168).|
|Inflammation||Incident heart failure is associated with inflammation (169). Diets rich in plant-based foods may reduce inflammation (170–172) adding a measure of protection against heart failure (35–38). In contrast, meats, particularly processed red meat, may increase inflammation, as shown by increasing serum levels of C-reactive protein (173,174). Furthermore, a Mediterranean diet vs. control is associated with reduced serum markers of inflammation (175). MMPs participate in inflammation: higher levels are associated with increased atherosclerosis and heart failure risk (176,177). A vegetarian diet is associated with decreased levels of MMP compared with an omnivorous diet, and hence may be protective (178).|
|Reactive oxygen species||Reactive oxygen species may induce interstitial fibrosis, myocyte hypertrophy, and aortic stiffness and contribute to the development of heart failure (179,180). Plant-based diets, with their high antioxidant content, may reduce oxidative stress and provide greater amounts of antioxidants than do non–plant-based foods (70). Accordingly, both a Mediterranean diet and a DASH diet were associated with greater serum antioxidant capacity vs. control (181,182). Furthermore, a vegetarian diet may be protective as it is associated with lower serum myeloperoxidase levels, a promoter of reactive oxygen species formation, vs. an omnivorous diet (178,183).|
|TMAO||TMAO is produced by intestinal bacteria as a byproduct of choline and L-carnitine metabolism (184). Increased TMAO levels are associated with vascular inflammation (185), platelet reactivity, decreased reverse cholesterol transport (184), cardiovascular disease (184,185), and heart failure severity (186,187). Plant-based diets reduce TMAO formation through favorable effects on gut microbiota, whereas animal-based foods may raise TMAO levels (184,188).|
LDL = low-density lipoprotein; MMP = metalloproteinase; TMAO = trimethylamine N-oxide.