Key Points:

– Cardiovascular diseases are the leading causes of death worldwide, taking almost 18 million lives every year

– Optimum gut health means having a right balance of good gut microbes against bad ones in our gut.

– Our gut health is associated with our cardiovascular health in 3 ways.

– Prebiotics could be used to enhance and regulate the health of the gut microbiota, thereby improving gut health and support our cardiovascular health.

Cardiovascular diseases are the leading causes of death worldwide, taking almost 18 million lives every year [1]. This group of diseases is comprised of conditions affecting the heart and blood vessels, including coronary heart disease, heart attack, and stroke being the more common ones. Some of the risk factors for developing heart diseases are [2]:

– High blood pressure (hypertension)
– High blood cholesterol
– Diabetes
– Obesity
– Lack of physical activity
– Excessive alcohol
– Smoking

Lifestyle changes such as diet modifications and increasing physical activities are ways to lower our risks of developing heart diseases. Here we explore how our gut health and microbiota affect our cardiovascular system.

All about gut health and the gut microbiota

Optimum gut health means having a right balance of good gut microbes against bad ones in our gut. This composition of microorganisms in our gut is collectively termed as gut microbiota. Our gut consists of trillions of such microorganisms, including bacteria, virus, fungi and protozoa species. This set of gut microbiota is unique to everyone and varies due to several factors including environmental, lifestyle, dietary habits, and consumption of medications such as antibiotics [3].

The good gut bacteria feeds on prebiotics, leading to the production of metabolites such as short-chain fatty acids (SCFAs) which confer health benefits to us. These benefits include healthy blood sugar [4] and pressure levels [5], and immune health [6]. The growth of good gut bacteria will in turn crowd out the bad ones, leading to a healthy balance of gut microbiota and optimum gut health.

This innate set of gut microbiota (the set that we are born with) is thought to be the most optimum for oneself, and this composition and amount of good gut bacteria decrease as we age, along with modern-day diets lacking in prebiotics (food for the good gut bacteria) and increased consumption of medications such as antibiotics.

3 ways our gut health is linked to cardiovascular system

Although anatomically distinct, our gut is intrinsically linked to our heart. Dysbiosis, which refers to the alteration of the gut microbiota balance, has been reported in patients with risk factors for cardiovascular diseases, such as hypertension [7]. Disruptions in gut microbiota can also lead to excessive accumulation of body fat in early ages [8].

Here are 3 ways the health of our gut affects cardiovascular health and the various cardiovascular diseases [9,10].

#1: Production of TMAO and its adverse effects on cardiovascular health

Trimethylamine N-oxide (TMAO) has been found to be associated with an elevated risk of cardiovascular diseases, as shown by research done by Wang et al. in 2011, published in the Nature journal [11]. Elevated TMAO levels were shown to accelerate atherosclerosis, which is a significant pathway in the development of cardiovascular diseases [11]. Other studies across the US and Europe have also generated similar results with regards to TMAO and its potential to increase cardiovascular disease risks [12,13]. Other than atherosclerosis, TMAO is also a strong predictor of clinical outcomes in patients with heart failure [14].

TMAO is produced mainly via a multistep pathway with the gut microbiota as the starting point. Our gut microbiota metabolizes certain types of nutrients including choline, phosphatidylcholine and carnitine into a compound called trimethylamine (TMA). This process is carried out by an enzyme called TMA lyase, which is encoded by certain type of gut microbial genes. TMA is subsequently oxidized into TMAO by certain types of liver enzymes. The precursors of TMAO (choline, phosphatidylcholine and carnitine) are mainly found in red meats, egg yolk and other meat products. Altered gut microbiota can result in an increase in the production of such toxic metabolites such as TMAO.

#2: Leaky gut hypothesis

In a healthy and normal state, there are mechanisms to ensure intestinal barrier function, including tight junctions, mucus production and immunity [9]. In heart failure patients, there is often impaired intestinal barrier function due to bowel wall edema, leading to this ‘leaky gut’ hypothesis [9]. This leaky gut will lead to gut bacteria and other bacterial products into the bloodstream, which can result in pro-inflammatory states for the body. This is usually correlated with heart failure symptom severity and poorer outcomes [15]. Studies have also shown that heart failure patients have higher endotoxin levels in the bloodstream [16]. Such leaky gut can be improved by improving the health of your gut microbiota, which can be done via taking prebiotics [17].

#3: Effects of SCFAs

SCFAs are produced from the fermentation of prebiotics by the gut microbiota. These metabolites include butyrate, propionate, and acetate. SCFAs have been shown to modulate several risk factors involve in cardiovascular diseases, such as blood pressure [18], lipid metabolism [19] and blood sugar homeostasis [20]. By modulating and reducing these blood markers, risk of developing cardiovascular diseases can be reduced. Recent studies have also suggested that SCFAs directly influence cardiac activities, such as repair of heart tissues after injury (such as heart attacks) [21].

How to improve gut health to positively affect our cardiovascular health?

One way to improve our gut health and gut microbiota composition is to take more prebiotics. Prebiotics act as food for the beneficial gut bacteria allowing them to grow and crowd out the harmful ones. By optimizing the balance of our gut microbiota, we improve our gut health which in turn support our cardiovascular system, through less production of toxic metabolites such as TMAO and increase production of beneficial ones such as SCFAs.

Restricting the types of food that give rise to TMAO may also be another lifestyle intervention that can help reduce risk of cardiovascular disease. Reducing intake of red meat can reduce our dietary carnitine and choline, thereby reducing TMAO levels as well.

Other benefits of optimum gut health

Other than the benefits on cardiovascular health, optimum gut health can also support the health of other body functions and systems, such as:

– Metabolic markers: blood pressure, sugar and cholesterol
– Immune health
– Nervous system
– Mental health
– Healthy aging
– Respiratory health
– Skin health

Conclusion

Cardiovascular diseases such as coronary heart disease, heart attacks and stroke are some of the most common diseases and causes of death worldwide, and cost billions of dollars in healthcare expenditure. Besides reducing your risks through lifestyle modifications, you can also consider optimizing your gut health. Taking prebiotics enhances the beneficial gut microbiota, which in turn helps improve gut health leading to reduction in risks of cardiovascular diseases.

Related Articles

Gut Health and Blood Pressure (Hypertension): How Are They Related?

Prebiotic: Gut Microbiota, Gut Health, and Beyond

Good Gut Health Is Linked To Lower Cholesterol Levels

References

1. World Health Organization (WHO). Cardiovascular diseases.
2. Centers for Disease Control and Prevention (CDC). Know Your Risk for Heart Disease. 2019 Dec.
3. Rutsch A, Kantsjö JB., Ronchi F. The Gut-Brain Axis: How Microbiota and Host Inflammasome Influence Brain Physiology and Pathology. Immunol. 2020;11.
4. Larsen N, Vogensen FK, van den Berg FW, et al. Gut microbiota in human adults with type 2 diabetes differs from non-diabetic adults. PLoS One. 2010;5(2):e9085.
5. Richards E.M., Pepine C.J., Raizada M.K. et al. The Gut, Its Microbiome, and Hypertension. Curr Hypertens Rep. 2017;19:36.
6. Wu HJ, Wu E. The role of gut microbiota in immune homeostasis and autoimmunity. Gut Microbes. 2012;3(1):4-14.
7. Yang T, Santisteban MM, Rodriguez V, et al. Gut dysbiosis is linked to hypertension. Hypertension. 2015 Jun;65(6):1331-40.
8. Cho, I., Yamanishi, S., Cox, L. et al. Antibiotics in early life alter the murine colonic microbiome and adiposity. Nature. 2012;488,621–626.
9. Witkowski M, Weeks TL, Hazen SL. Gut Microbiota and Cardiovascular Disease. Circ Res. 2020 Jul 31;127(4):553-570.
10. Trøseid M, Andersen GØ, Broch K, Hov JR. The gut microbiome in coronary artery disease and heart failure: Current knowledge and future directions. EBioMedicine. 2020 Feb;52:102649.
11. Wang, Z., Klipfell, E., Bennett, B. et al. Gut flora metabolism of phosphatidylcholine promotes cardiovascular disease. Nature. 2011;472,57–63.
12. Tang WH, Wang Z, Levison BS, et al. Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. N Engl J Med. 2013 Apr 25;368(17):1575-84.
13. Li XS, Obeid S, Klingenberg R, et al. Gut microbiota-dependent trimethylamine N-oxide in acute coronary syndromes: a prognostic marker for incident cardiovascular events beyond traditional risk factors. Eur Heart J. 2017 Mar 14;38(11):814-824.
14. Tang WH, Wang Z, Fan Y, et al. Prognostic value of elevated levels of intestinal microbe-generated metabolite trimethylamine-N-oxide in patients with heart failure: refining the gut hypothesis. J Am Coll Cardiol. 2014 Nov 4;64(18):1908-14.
15. Munger MA, Johnson B, Amber IJ, et al. Circulating concentrations of proinflammatory cytokines in mild or moderate heart failure secondary to ischemic or idiopathic dilated cardiomyopathy. Am J Cardiol. 1996 Apr 1;77(9):723-7.
16. Niebauer J, Volk HD, Kemp M, et al. Endotoxin and immune activation in chronic heart failure: a prospective cohort study. Lancet. 1999 May 29;353(9167):1838-42.
17. Camilleri M. Leaky gut: mechanisms, measurement and clinical implications in humans. Gut. 2019 Aug;68(8):1516-1526.
18. Jose PA, Raj D. Gut microbiota in hypertension. Curr Opin Nephrol Hypertens. 2015;24(5):403-409.
19. Korcz E , Kerényi Z , Varga L. Dietary fibers, prebiotics, and exopolysaccharides produced by lactic acid bacteria: potential health benefits with special regard to cholesterol-lowering effects. Food Funct. 2018 Jun 20;9(6):3057-3068.
20. Cunningham, A.L., Stephens, J.W., Harris, D.A. Gut microbiota influence in type 2 diabetes mellitus (T2DM). Gut Pathog. 2021;13,50.
21. Tang TWH, Chen HC, Chen CY, et al. Loss of Gut Microbiota Alters Immune System Composition and Cripples Postinfarction Cardiac Repair. Circulation. 2019 Jan 29;139(5):647-659.

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