Valentine’s day reminder: love your heart by exploring the Gut/Heart connection
Valentine’s day offers an excuse to perform romantic gestures and bestow material tokens of our love, such as flowers and chocolate upon our loved ones. It has also become an opportunity to bring awareness to heart health. While it is my hope that both our loved ones and our heart health are being celebrated and attended to daily, the annual reminder is welcome. What a wonderful invitation to check in with ourselves and take inventory of our health and well-being.” Afterall, truly loving others begins with self-love, and a fundamental aspect of self-love is taking care of our physical body. When we prioritize our own health (our cardiovascular health), we send the message to those we love that we are committed to being present for them, and set an example for our loved ones that self-care is not selfish.
With cardiovascular disease ranking as the leading cause of death worldwide and the cause of one in every three deaths in the US (1,2 ) you may be wondering what preventative strategies you can take to reduce your risk. While the potential to develop CVD does have a genetic component, with family history of CVD as a well-established risk factor, lifestyle factors such as diet, exercise, and stress management have an equally significant role to play. These lifestyle factors also happen to be the ones of which we have a certain degree of control.
Recent research has implicated the role of the microbiome in cardiovascular disease risk. (1, 2, 3) The microbiome refers to the bustling community of trillions of microbes (bacteria, viruses, fungi, etc.) that reside primarily in the gut, but also inhabit our skin, mouth, vaginal tract and other areas of the body. None of these microbes are inherently “good” or “bad,” but when certain bacteria grow out of control, this can lead to an imbalance in the microbiome that can have negative consequences. This imbalance is often referred to as dysbiosis and these bacteria that can be problematic when elevated are often referred to as “opportunistic.” Nevertheless, this microbial network plays a crucial role in our overall health, and here we will be focusing more closely on the connection between the microbiome and cardiovascular health.
Microbiome Basics
This diverse community of bacteria, viruses, and fungi that make up the gut microbiome support energy metabolism, digestion, synthesis of specific vitamins, immune health, regulation of the intestinal barrier, and influence inflammation. In addition, this microbial ecosystem is responsible for the production of various metabolites (byproducts of metabolism) such as short chain fatty acids (SCFA), secondary bile acids, neuroactive compounds (aka serotonin), and polyphenol metabolites with anti-inflammatory action. The formation and balance of these metabolites have a profound impact on physiological processes involved in health and disease. (1,2)
According to emerging research, changes in the composition and diversity of gut bacteria have the potential to influence risk factors associated with heart disease. These risk factors include cholesterol levels, plaque formation, blood pressure, and inflammation. Atherosclerotic plaques for example, exhibit bacterial profiles containing certain species of gut bacteria linked to dysbiosis, and inflammatory compounds associated with inflammation, are also linked to such microbial disturbance; inflammation is a well-established precursor to cardiovascular disease. A microbiome with greater diversity, a strong presence of a bacterial family called Akkermansia, and a lower Firmicutes to Bacteroidetes ratio on the other hand, is positively associated with plaque reduction. (1,4)
The characteristics of a healthy microbiome have yet to be defined. Likewise, the exact mechanisms of action linking dysbiosis and CVD pathogenesis remain unclear. Nonetheless, current literature linking the two highlights several of the metabolites involved. (1) Below are a few of the metabolites under review:
Short Chain Fatty Acids
SCFAs which include butyrate, acetate, and propionate, generated when friendly gut bacteria ferment specific fibers in the large intestine (colon), are one of these metabolites. Generally considered to exert a beneficial effect on health, these are involved in immune health, intestinal barrier function, and have anti-inflammatory properties especially within the colon. Without adequate dietary fiber we fall short on production of these SCFAs. Although these are generally considered to be beneficial, there is some evidence to suggest that elevated SCFAs in the feces correlates to metabolic syndrome, diabetes, and CVD. (1) For this reason balance seems to be key.
TMAO
Some microbial species metabolize foods rich in choline and carnitine into a metabolite called trimethylamine-N-oxide (TMAO). Choline rich foods include eggs, fish, and dairy, while red meat is a major source of carnitine. Research implicates this metabolite in the development of atherosclerosis and cardiovascular disease which may partially explain the red meat connection with CVD. (1,2) Interestingly, resveratrol, a polyphenol, seems to have the capacity to reduce TMAO levels according to some studies, further making the case for a plant-fiber-rich diet of which polyphenols originate. As one author noted, “reducing L-carnitine or choline levels in the diet is not a good alternative, as these are important nutrients.”(3) It may be that a balanced diet that includes choline and carnitine does not present with problematic levels of TMAO when accompanied by an abundance of fruits and vegetables.
Secondary Bile Acids
Bile acids play an important role in the absorption of dietary fats and fat-soluble vitamins. They also act as signaling compounds involved in communication between cells, tissues, and organs to coordinate physiological processes. Bile acids also have a cholesterol-lowering effect, aiding excretion of cholesterol through the stool (poop). However, certain gut microbiome profiles have the capacity to reduce bile acid production, leading to increased circulating LDL cholesterol levels and plaque build-up. (1)
Polyphenol Metabolites
Polyphenols are naturally occurring compounds derived from plant foods such as fruits and vegetables that are widely known for their antioxidant properties. Gut bacteria assist in the degradation of polyphenols into their smaller units containing this antioxidant activity. Antioxidants play a vital role in counteracting inflammation and inflammation plays a major role in the development and progression of cardiovascular related conditions. Chronic inflammation within the arterial walls can weaken them, making them permeable to lipids and immune cells that together build up to form atherosclerotic plaques, increasing risk of heart attack and stroke. It appears that plaque is lower among CVD subjects with microbiomes enriched with Akkermansia, a bacterial family associated with higher polyphenol and fiber intake. (4,5)
Gut Permeability
Disruption of the balance of beneficial and “opportunistic” bacteria is associated with changes to the integrity of the intestinal barrier. This barrier is the site of nutrient absorption, as well as a large portion of the immune system, preventing the passage of pathogens and other harmful substances from entering into circulation. When the gut barrier is compromised, this can lead to bacterial translocation, or migration of bacterial derived metabolites that end up in systemic circulation. It has been reported that “after ischemic or hemorrhagic stroke 50% of patients experience gastrointestinal issues, including gut microbiota dysbiosis, leaky gut, increased gut motility disorganization, and gut hemorrhage, as well as a reduced diversity and composition of the microbiome.” (1) Whether gut permeability precedes CVD or a cardiovascular event triggers “leaky gut,” remains to be determined. Further research is likely needed to fully understand the directionality of these gut/cardiovascular pathways. what this does tell us however is that gut health may play an important preventative role in minimizing the inflammation that can lead to CVD.
Dietary and Lifestyle Strategies
Polyphenols-include plenty of colorful fruits and vegetables-these contain those antioxidant-rich polyphenols mentioned above-examples of polyphenols include resveratrol, quercetin, curcumin, and egallic acid-foods such as olive oil, dark chocolate, tumeric, grapes and berries
Fiber-Soluble Fiber-this type of fiber slows digestion and absorption by producing a gel-like substance during digestion- this gel-like substance has a cholesterol-lowering effect by way of trapping bile and cholesterol for excretion and acts as a prebiotic providing fuel for gut bacteria so they can produce the SCFAs and other metabolites detailed earlier-oats, beans, avocado, brussel sprouts and chia are great sources of this fiber; Insoluble Fiber-reaches the large intestine relatively intact and provides fuel for the gut microbiota so they can make the metabolites discussed above-sources of insoluble fiber include most grains, nuts, and vegetables
Probiotic-rich foods-these contain well-researched beneficial bacterial strains found in the human microbiome that confer the above benefits-look for fermented foods such as kefir, yogurt, kombucha, kimchi, and sauerkraut-probiotic supplements are another option that you might consider- seek the help of your wellness professional when selecting the right probiotic
Processed foods-limit overly processed foods especially refined carbohydrates and added sugars-these often contribute to dysbiosis and provide fuel to opportunistic microbes
Exercise-aside from the more well-established benefits of exercise on the cardiovascular system such as increased blood flow and reduction in inflammatory abdominal fat, exercise is associated with an increase of various metabolites mediated by the microbiome including SCFAs and serotonin, as well as desirable bacterial profiles. The bacteria that appear more sensitive to the impact of exercise are those in the lactobacillus family, the same family often responsible for producing serotonin (6). Some studies however, link very strenuous exercise with inflammatory chemicals and gut permeability (7)
Stress-although a link between stress and the microbiome has been identified with stress negatively impacting diversity and richness of this microbial community with implications for neurodegenerative disease progression, the research and thus our understanding remains limited. (7) Nevertheless, taking action to reduce stress and implement stress management practices is highly encouraged to support a microbiome for optimal health. Exercise, yoga, and other mindfulness practices such as meditation and breathwork are all effective approaches to minimizing stress.
Conclusion
The mortality rates associated with cardiovascular disease in developed nations are alarming. While understanding the relationship between the gut and the cardiovascular system may help facilitate the development of novel prevention strategies for CVD, there are some basic actions we can take right now to reduce our risk. Getting regular check ups with your health care provider is an essential component of any preventative care strategy. Along with routine evaluations, we can proactively manage risk factors, such as making informed dietary choices, engaging in regular exercise, and implementing stress management strategies. Practicing self-care in this way sets a powerful example to those we love to prioritize their own well-being.
About Carla
Carla Abate is a Board Certified Holistic Nutritionist in Lakewood, CO, specializing in functional nutritional strategies for women and families. She is a Restorative Wellness Solutions Practitioner, a Certified Nutrition Therapist Master, and a Postpartum Doula. She also holds a Master's degree in Counseling. Carla is dedicated to fostering health and wellness through evidence-based nutrition coaching and functional testing.
To learn about personalized nutrition strategies for your health needs, contact Carla at 720-665-2300 or schedule a complimentary consultation.
References
https://pubmed.ncbi.nlm.nih.gov/31469291/
https://pubmed.ncbi.nlm.nih.gov/28360349/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7824497/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10005405/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10005405/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6748614/
https://pubmed.ncbi.nlm.nih.gov/31628992/