Gut to Heart: Uncovering the Surprising Link Between Atrial Fibrillation and Gut Health

Gut health has long been associated with digestion and immune function, but recent research suggests it might also play a significant role in heart health. For individuals with atrial fibrillation (Afib), the balance of bacteria in the gut could be more important than you think. Imbalances in the gut microbiome may contribute to inflammation, trigger irregular heart rhythms, and even worsen Afib symptoms. By understanding how your gut and heart are connected, you can make informed decisions about diet and lifestyle changes that may help reduce the risk of Afib episodes and support overall heart health.

Key points:

The gut microbiome: an overview

What is the gut microbiome?

The gut microbiome is the collection of microorganisms, including bacteria, viruses, and other cells, that live in the human gastrointestinal tract, particularly in the colon. These microorganisms play a crucial role in digestion by breaking down sugars and proteins. In addition to digestion, the gut microbiota support immune function, control nutrient metabolism, and prevent the growth of harmful pathogens. A balanced gut microbiome is essential for maintaining overall health, as it influences immunity and metabolism.

The gut microbiome is closely linked to cardiovascular health through various metabolic pathways and signaling molecules. An imbalance in gut microbiota composition, influenced by factors like diet, antibiotic use, and genetics, has been associated with cardiometabolic diseases.

How gut health impacts the heart

Gut microbiota imbalances can contribute to atherosclerosis, coronary artery disease, myocardial infarction, hypertension, and heart failure. Disruption of the gut microbiota composition is called dysbiosis and this influences the progression of cardiovascular risk factors.

Recent evidence highlights the role of gut microbiota and its metabolites in Afib pathogenesis by affecting inflammation, fibrosis and  ion channel activity.

Structural remodeling and inflammation 

Gut dysbiosis increases the risk of Afib by triggering inflammation. This inflammation occurs due to increased secretion of pro-inflammatory molecules called cytokines. These promote atrial fibrosis and structural remodeling. Studies in animal models confirm that gut microbiome imbalances amplify fibrosis and inflammation, while inhibition of gut-associated inflammatory molecules reduces risk of atrial fibrillation.

High-fiber diets or short-chain fatty acid (SCFA) supplementation have been shown to mitigate atrial enlargement, fibrosis, and electrical instability in animal models. Both fiber and SCFAs regulate gut homeostasis so this can help with gut inflammation and reduce dysbiosis.

Electrical remodeling and gut health

Electrical remodeling in Afib involves changes in ion channel activity, shortening of the refractory period, increased potassium currents, and impaired conduction. Gut microbiota metabolites can exacerbate these changes, making atrial fibrillation more likely to persist.

In mice, excessive inflammatory protein activation due to gut microbiome suppression led to abnormal Ca2+ handling, which promoted arrhythmias. Additionally, bile acids can alter membrane potentials and contribute to arrhythmias by activating ion channels. Intestinal metabolites can also alter connexin proteins, which normally create the pathway through which the electrical impulses travel and allow for cell-to cell communication. This alteration further promotes Afib by disrupting electrical signaling between heart cells. These findings highlight how gut health influences the electrical properties of the heart and its role in Afib.

Strategies to improve gut health for a stronger heart

Dietary changes for a healthier gut

Polyphenols are compounds known for their antioxidant properties and eating foods such as fruits,vegetables, whole grains, legumes and nuts, which are naturally rich in polyphenols, promote better gut health and can help with inflammation. Polyphenols promote the growth of healthy microorganisms including many well known probiotics.

Additionally, it is important to reduce processed foods, excessive sugar, and red meat to prevent gut imbalances and promote better heart health.

Probiotics: can they help?

Probiotic products are labelled as “functional foods” as they include a specific compound that is designed to improve the health of the consumer. The amount of probiotic microorganisms can be intentionally increased in products such as yogurts and other fermented products. These types of products can be powerful antioxidants and help to reduce oxidative damage caused by reactive oxygen species. It is recommended to include probiotic products in your diet for improved gut health.

Exercise and gut health

A review found that exercise can have a beneficial impact on gut health. Moderate, moderate-to-high and high-intensity exercise all had a positive effect on gut health. It was shown that engaging in exercise increased gut health promoting bacteria. Additionally, exercise frequency played a role, with higher weekly sessions generally leading to greater gut microbiota diversity, though even 2–3 sessions per week showed some positive effects. Regular exercise supports gut microbiome diversity, and overall heart health.

Based on the previous research mentioned, diet and lifestyle have a huge effect on gut health. Eating a balanced and varied diet, which includes probiotics, as well as incorporating regular exercise into your routine can improve your health and help prevent health issues. As seen in the studies referenced above, taking gut health into account can also help prevent Afib and reduce its severity.