The Gut-Heart Connection: Functional Medicine's Approach to Cardiovascular Health

Emerging science is showing more and more impacts that the microbes in your gut have on the rest of your body and health, and your heart is no exception. Research is expanding to understand the importance of the gut-heart connection in functional medicine. 

Functional medicine takes a holistic approach to understanding and addressing health. This approach considers the ways in which factors like nutrition, genetics, microorganisms, intestinal permeability, hormonal changes, movement, stress, and other lifestyle components contribute to imbalances and the development of diseases.

One such area where functional medicine can make a significant impact is by addressing the dynamic interactions among the gut microbiota, the intestinal barrier, and systemic inflammation that contribute to the development of cardiovascular disease. Functional medicine strives to address each individual’s heart health needs by taking a comprehensive view of how gut health contributes to cardiovascular health.

This article will dive deeper into the pathophysiology of the gut-heart axis and how you can optimize the health of both your gut and heart.

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What is the Gut-Heart Axis?

The gut-heart axis refers to the complex interplay between the microbes in your gastrointestinal tract and cardiovascular function. Your digestive tract is home to trillions of microbes that compose your unique microbiome. Research has shown that these microbes are critical for your health, assisting with important processes such as digesting nutrients, regulating immune function and inflammation, maintaining the intestinal barrier, producing vitamins, hormones, and metabolites, and impacting the function of major organs like your heart. 

Emerging science shows that the gut microbiota has a significant impact on the occurrence, progression, and treatment of cardiovascular diseases. Cardiovascular diseases include those impacting the heart and blood vessels. These conditions, such as coronary artery disease, stroke, heart failure, and arrhythmias, impact millions of people worldwide. 

Inflammation is an important part of your body’s response against harmful threats like pathogens, tissue injury, or irritants. When acute and self-contained, this protective mechanism helps to eliminate damaged cells and initiate tissue repair. But if inflammation becomes ongoing and chronic, it can contribute to the development of many chronic diseases, including those impacting the cardiovascular system. 

For example, inflammation within your blood vessels is a significant contributor to the development of atherosclerosis, which can lead to heart attack and stroke. Chronic inflammation also contributes to other conditions associated with cardiovascular health, such as heart failure, high blood pressure (hypertension), chronic kidney disease, obesity, and type 2 diabetes.

Gut Health and Its Impact on Cardiovascular Disease

Understanding the gut-heart axis requires looking at the physiology involved. The microbes in your intestines impact many of the factors involved in the development of cardiovascular diseases, influencing inflammation, intestinal barrier function, vasculature, nervous system function, hormones, and immune health, all of which are linked with cardiovascular health.

These connections between gut health and heart disease seem to be mediated by several pathways. Imbalances in gut microbes (dysbiosis), metabolites generated by your gut microbiota, and related signaling pathways all play a part in the microbiome’s impact on cardiovascular health. 

A balanced gut microbiota is home to a variety of microbes. The most common bacteria in a healthy gut microbiome include Firmicutes and Bacteroidetes, which account for almost 90% of the total number of gut microbiota, as well as Proteobacteria and Actinobacteria. People with cardiovascular diseases have skewed compositions of bacteria and ratios of these microbes. 

A major contributor to chronic systemic inflammation is dysbiosis in the gut. The microbes in your gut release many mediators that influence inflammation and the function of your immune system. For example, a healthy microbiome metabolizes dietary fibers to produce important metabolites like short-chain fatty acids (SCFAs) that help to regulate inflammation. 

On the other hand, an imbalance in gut bacteria can contribute to a leaky gut barrier that allows toxins produced by dysbiotic bacteria to leak into your bloodstream (metabolic endotoxemia). These inflammatory bacterial endotoxins, particularly lipopolysaccharides (LPS), contribute to systemic inflammation and the risk of cardiovascular disease.

In addition to impacting inflammation, your gut microbiome influences the production and metabolism of hormones and neurotransmitters, which impact cardiometabolic health. Microbes contribute to the production of hormones in the gut that influence appetite, food intake, and energy metabolism, influencing weight, metabolic function, insulin, and blood sugar balance. These can influence risk factors for cardiovascular disease like metabolic syndrome and type 2 diabetes.

The intestinal microbiota plays a crucial role in the neuroendocrine system and gut-brain axis. This system impacts the hypothalamic–pituitary–adrenal (HPA) axis to regulate your response to stressors, blood pressure, and vascular response. Neurotransmitters produced in the gut influence heart function and disease risk. For example, serotonin, dopamine, and acetylcholine impact heart rate and vascular function.

Another pathway that facilitates the gut-heart axis and contributes to inflammation is the trimethylamine (TMA) or trimethylamine N-oxide (TMAO) pathway. TMA is produced when the gut microbiota metabolizes dietary nutrients that possess choline, phosphatidylcholine, and L-carnitine, rapidly oxidized into TMAO in the liver, and released into the blood, where it is cleared by the kidneys. 

Elevated levels of TMAO occur with dysbiosis and are correlated with an increased risk of cardiovascular disease and related complications since TMAO seems to alter cholesterol metabolism, impact inflammation, cause vascular endothelial dysfunction, and lead to platelet activation.

Functional Medicine Approach to Gut and Heart Health Assessments

Functional medicine for cardiovascular health investigates these underlying issues that throw the gut-heart axis out of balance and develops a personalized management approach to bring balance back to the microbiome and body. This type of holistic approach to gut and heart health aims to restore health to the microbiome and address root causes and interconnected systems of the body rather than just treating resulting symptoms.

Functional medicine laboratory testing can help evaluate gut health and ways that it may be impacting cardiovascular health. This type of evaluation assesses the balance of the gut microbiota to identify potential dysbiosis. It also looks at factors such as gut permeability, inflammation, and metabolites like TMAO and LPS that play important roles in the gut-heart axis. 

Comprehensive gut testing, including an analysis of the gut microbiome, is central to this approach since dysbiosis plays a key role in driving many of the risk factors for cardiovascular diseases. The GI-MAP+Zonulin by Diagnostic Solutions is a stool analysis that provides a comprehensive qPCR analysis of over 50 beneficial and harmful bacteria, viruses, parasites, and yeast that may be part of your microbiome. 

This test also measures markers of digestion and absorption, intestinal inflammation, and microbial metabolism to evaluate these important potential factors in heart health. It also measures zonulin to help assess levels of intestinal permeability

Healthy gut microbes play important roles in regulating your gut mucosal barrier function, maintaining intact tight junctions so that toxins do not enter your bloodstream, and regulating normal mucosal immunity. 

To assess intestinal barrier function in more detail, the Advanced Intestinal Barrier Assessment from Precision Point Diagnostics can be used. This test measures markers of intestinal permeability, including zonulin, DAO, and LPS, that can indicate a leaky gut barrier that may be contributing to systemic inflammation and heart disease. 

As discussed above, TMAO is correlated with cardiovascular disease and mortality. The TMAO test by BostonHeart Diagnostics quantifies circulating levels of TMAO in the blood after an 8-12 hour fast. 

Micronutrient deficiencies are associated with heart disease as well as issues with gut health. Inadequate levels of vitamin A, magnesium, selenium, and vitamin D have been associated with heart failure. A leaky gut barrier and an imbalanced microbiome can contribute to nutrient deficiencies. 

Over 125 nutritional biomarkers can be measured with the NutrEval by Genova Diagnostics to help identify nutritional deficiencies and insufficiencies that may be a result of and/or contributing to poor gut and heart health. 

Organic Acid testing, like the one offered by Mosaic Diagnostics, is another way to assess nutrition and metabolic function. This test comprehensively analyzes overall health, including intestinal microbial overgrowth, the nutritional status of various vitamins and minerals, and detoxification function using urine testing. This information is valuable in assessing imbalances in gut and metabolic health that may be impacting cardiovascular disease risk and can help guide a comprehensive treatment plan to address gut, metabolic, heart, and overall health.

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Dietary Strategies for Optimizing Gut-Heart Health

Functional medicine aims to rebalance the body by developing an individualized management approach targeting specific underlying issues. Treatment strategies aim to restore balance to the gut-heart axis using dietary modifications, probiotics, prebiotics, and lifestyle changes to optimize gut health and positively impact cardiovascular outcomes.

Adequate nutrition is needed for optimal cardiovascular health. Research supports a whole-foods-focused Mediterranean diet to favorably shape the gut microbiome and improve cardiovascular health. This way of eating focuses on a variety of seasonal plant-based foods like vegetables, fruits, and whole grains in addition to herbs, spices, fish, and healthy fats like olive oil. ​​

Many studies show that an anti-inflammatory way of eating, like the Mediterranean diet, is associated with a significantly lower risk of cardiometabolic diseases, in part by improving levels of insulin, glucose, cholesterol, triglycerides in the body, and body fat composition. 

Adequate micronutrients and phytonutrients are also important for the health of your gut and cardiovascular system. For example, deficiencies in vitamin D and omega-3 levels are associated with a higher risk of CVD and gut dysbiosis. 

Vitamin D is primarily obtained by exposing your skin to UVB radiation from the sun. The American Heart Association recommends eating at least two servings (3 ounces cooked or ¾ cup flaked) of fatty fish like salmon, mackerel, sardines, and anchovies each week to consume omega-3 fatty acids as well as dietary vitamin D. Plant-based sources of omega-3 fats include flaxseeds, chia seeds, hemp seeds, and walnuts.

Role of Probiotics and Prebiotics

Rebalancing the gut microbiome with targeted nutrition and supplementation can help to heal the intestinal barrier, reduce systemic inflammation, and improve heart health. Probiotics and prebiotics can be incorporated into your diet and/or supplementation routine to support gut health and benefit heart health. 

Eating and/or supplementing your diet with prebiotic dietary fibers and resistant starches helps to feed the healthy bacteria that naturally produce short-chain fatty acids like butyrate. This helps to promote a balanced microbiome and can help to regulate the repair of the intestinal mucus barrier. 

Probiotics are beneficial living microorganisms that help to improve the diversity and balance of your microbiome. Probiotics occur naturally in fermented foods like yogurt, kefir, sauerkraut, miso, and kombucha and/or can be taken as supplements. This approach helps to support the populations of good bacteria in the gut and prevent an overgrowth of harmful microorganisms.

Certain probiotic strains may be particularly helpful for heart health. Emerging evidence shows that probiotics and prebiotics can also help to rebalance the gut microbiota, leading to decreased TMAO and fewer atherosclerotic lesions. Other studies suggest that Bifidobacterium brevis can reduce the death of intestinal epithelial cells and intestinal inflammation. Oral probiotic supplementation with commensal bacteria such as Bifidobacterium seems to improve the function of the intestinal barrier and inhibit the growth of harmful bacteria. You can work with your practitioner using functional medicine testing to develop an individualized approach for your unique needs. 

Lifestyle Modifications for Gut-Heart Health

Lifestyle changes for gut-heart health are also an important part of a functional medicine strategy. Research shows that chronic stress, insufficient exercise, inadequate sleep, and smoking are associated with dysbiosis in the gut, increased chronic inflammation, and an elevated risk of cardiovascular disease. Lifestyle approaches such as managing stress, engaging in adequate physical activity, and avoiding smoking can all improve gut health and reduce your risk for cardiovascular diseases. 

Managing stress for heart health and gut balance is a very important step for balancing your gut-heart axis. Stress increases inflammation, worsens leaky gut, and contributes to dysbiosis via the gut-brain axis, increasing activation of the sympathetic nervous system and stress hormones like cortisol. Regularly engaging in mind-body practices like yoga, meditation, breath work, and biofeedback helps to activate your body’s parasympathetic nervous system and relaxation response. 

Regular balanced physical activity is a great way to reduce chronic stress and improve gut microbial diversity, inflammation, and cardiovascular health. Most people benefit from at least two to three hours of moderate-intensity aerobic and strength training exercises each week. In addition to cardiovascular exercises and strength training, meditative exercises like tai chi, qigong, and yoga have been shown to help treat cardiovascular diseases such as hypertension and heart failure.

In addition, optimal restorative sleep is essential for the health of your gut and heart. A regular sleep schedule can help you optimize sleep duration and quality and maintain regulated circadian rhythms that impact your gut microbiome and cardiovascular disease risk. 

Smoking is a major modifiable risk factor for heart disease and also impacts the composition and metabolomic profile of the gut microbiome. Improvements in gut parameters and cardiovascular disease risk factors are seen after cessation of smoking. 

Challenges and Future Directions

The gut-heart connection has many implications and presents exciting opportunities for the future of gut-heart health. Currently, challenges in gut-heart research revolve around aspects like clarifying the mechanisms behind the gut-heart axis and further understanding how the gut microbiome produces various metabolites and impacts.

As more high-tech means are developed to sequence bacterial genes, science will be able to more clearly understand gut microbiota metabolites and therebyformulate more effective targeted interventions.

For example, fecal microbiota transplantation (FMT) is being studied for treating cardiovascular health by improving the composition of the gut microbiome. FMT introduces fecal contents from healthy subjects into the gastrointestinal tract of someone with health challenges. This has been shown to improve obesity by increasing butyrate-producing bacteria, improving glucose balance and insulin sensitivity, sustaining weight loss, and encouraging microbial diversity. FMT has also been shown to improve blood pressure by healing intestinal permeability and increasing the number of SCFAs-producing bacteria.

One area of emerging research into balancing the gut-heart axis is using traditional Chinese medicine (TCM). Research shows that TCM can improve many aspects of gut health and help reduce the risk of heart disease. Utilizing TCM can improve intestinal barrier function and regulate the synthesis of SCFAs and neurotransmitters that impact metabolic and cardiovascular health. Studies show that the beneficial impacts of TCM on the gut microbiome can also improve cardiovascular risk factors. For example, TCM can improve hypertension by regulating gut microbiota.

Another area of emerging research is investigating the association between TMAO levels and adverse cardiovascular consequences. Microbial TMA-lyase inhibitors are being researched for their ability to reduce TMAO and improve cardiac function and fibrosis.

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Gut-Heart Connection: Key Takeaways

The gut microbiome is crucial for so many processes throughout the body, including having significant impacts on cardiovascular health. Functional medicine provides a comprehensive approach to evaluating factors involved with the gut-heart axis. This allows for a holistic and individualized management approach to bring the gut back into balance and improve cardiovascular disease risk factors. 

Considering the gut-heart axis as part of a comprehensive approach to patient care offers a powerful way to bring greater health to the whole individual while reducing the occurrence and progression of cardiovascular diseases.

Utilizing a functional approach that incorporates diet, lifestyle, and supplementation helps to rebalance the gut microbiome, heal intestinal permeability, and improve gastrointestinal health. In turn, this can help improve systemic inflammation, balance the immune system, and reduce risks of cardiovascular disease.