Diet-Mediated Heart Disease Risk via the Gut Microbiome

Background: Recent advances in microbiome research suggest the gut microbiome has a role to play in the development of coronary artery disease (CAD). Though the American Heart Association (AHA) has broad dietary recommendations to prevent CAD, the role of the gut microbiome is not considered. The aim of this study is to examine existing literature on the role of probiotics (fermented dairy), prebiotics (high-fiber foods), and processed foods (NOVA groups 3 and 4) on markers of atherosclerosis via the gut microbiome. Methods: A search was conducted for human intervention studies using PubMed, CINAHL, and Embase. Twenty-two articles met eligibility and were included in this review. Results: Probiotic ingestion decreased low-density lipoprotein and total cholesterol and increased short chain fatty acid (SCFA) production, especially butyrate. Prebiotic ingestion had no effect on inflammatory markers, and effects on SCFAs and blood lipids were variable. The best outcomes were seen with almonds, walnuts, whole apples, resistant starch, and multi-fiber bread. Processed foods tended to exhibit pro-inflammatory, pro-cholesterol, and anti-SCFA effects, especially when fiber was artificially removed. Non-nutritive sweeteners did not alter any markers, while refined grains increased CRP, Il-6, and IL-1β. Some even recorded a decrease in SCFAs and an increase in blood lipids from baseline. No trial was powered to detect significance at the metagenomic level, but trends between bacterial species and SCFAs, CRP, Il-6, and blood lipids were seen throughout the literature. Conclusion: Findings suggest that probiotic, prebiotic, and processed foods may play an important role in the development of CAD via the gut microbiome. Interindividual variation across the prebiotic literature suggests that AHA guidelines on fiber may be overstated, and diet education for CAD prevention may benefit from the inclusion of a microbiome context. Further research is needed to examine the relationship between microbiota and atherogenesis in human subjects.