Impact of Facilitated Vegan Diet on Cardiometabolic Endpoints and Trimethylamine N-oxide

This study will compare the impact of a vegan diet to a non-vegan diet, when provided with meal kits in participants who are overweight.

A vegan diet includes foods that come from plants and excludes foods that come from animals like meat, dairy, and eggs. Dietary modifications such as adopting a vegan diet are associated with significant improvements in cardiometabolic parameters, making it one of the preferred treatment options for obesity and preventing associated health conditions. Meal kits are packages that include: a quick (~30-45 minutes) and simple recipe, all the recipe's required ingredients, and are conveniently delivered to patient homes. In this study, a facilitated vegan diet is defined as a change from an omnivorous diet to a vegan diet with the aid of boxed vegan meal kit delivery. A facilitated vegan diet has shown LDL-c and weight improvements over continuing an omnivorous diet in a preliminary study.

TMAO, changes in gut microbiome, and compliance to dietary modification impact cardiovascular and overall health. TMAO is a diet dependent biomarker for CVD, as elevated TMAO levels are associated with a 62% increased risk of heart attack, stroke, or death. TMAO increases platelet hyperactivity, inflammation, and foam cell generation, all of which contribute to atherosclerosis and may explain the increased risk of CVD. Additionally, TMAO predicts risk of major adverse cardiovascular events independently of other cardiovascular risk factors.

Consumption of animal products elevate TMAO levels due to its abundance of TMAO precursors: choline and carnitine. Chronic dietary red meat was associated with increased TMAO levels over white meat and non-meat protein. One study found that consuming plant-based alternative meat products improved TMAO levels over a mostly red meat diet. Both study interventions replaced protein sources but did not remove animal products such as eggs and dairy, which have conflicting evidence relative to TMAO. This study intervention will have participants adopt a full vegan diet, eliminating animal products.

The gut microbiome plays a crucial role in converting dietary precursors into TMAO. TMAO levels post l-carnitine ingestion were significantly higher in patients on a long-term omnivorous diet vs patients on a long-term vegan or vegetarian diet. This suggests that the gut microbiome in a plant-based diet lowers the formation of TMAO via the diet. This study will explore changes in gut microbiome from a dietary intervention in relation to TMAO and explore if these changes are sustained after discontinuing a 4-week facilitated vegan diet. Additionally, changes in gut microbiome will be explored in relation to microbiota changes seen in other disease states such as anxiety, irritable bowel disease, and other inflammatory diseases.