- Chronic Obstructive Pulmonary Disease (COPD) is estimated to be the third leading cause of death worldwide.
- Our gut and lungs communicate bi-directionally via the gut-lung axis. Gut health and microbiota are involved in respiratory diseases such as COPD through this gut-lung axis.
- A healthy and balanced gut microbiota may improve our respiratory health and reduce the risk of COPD.
- The use of prebiotics to induce positive changes to our gut microbiota and improve our gut health is one option we can consider to improve our respiratory health and reduce the risk of COPD.
Chronic Obstructive Pulmonary Disease (COPD) is a term used to describe a group of respiratory diseases that cause airflow blockages and breathing difficulties. COPD is associated with chronic inflammation of the airways and includes emphysema and chronic bronchitis [1]. The World Health Organization (WHO) estimates COPD to be the third leading cause of death worldwide, causing more than 3 million deaths in 2019 alone [2]. In the United States, an estimated 16 million people are diagnosed with COPD [3].
Recent studies have discovered that our gut and lungs communicate bi-directionally via the gut-lung axis. Gut health and microbiota are involved in respiratory diseases such as COPD through this gut-lung axis. Read on to find out more about how a healthy and balanced gut microbiota may improve our respiratory health and reduce the risk of COPD.
Our gut consists of trillions of such microorganisms, including bacteria, viruses, 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 [4].
This innate set of gut microbiota (the set that we are born with) is thought to be the most optimum for oneself. This optimum composition deteriorates as we age. Along with poorer modern-day diets lacking in prebiotics (food for the good gut bacteria) as well as increased use of medications, the composition and amount of good gut bacteria decrease even faster.
An optimum gut microbiota consists of a healthy balance of both good and bad gut bacteria species, which leads to good gut health.
Smoking is the biggest risk factor for COPD. Approximately 90% of COPD cases are caused by smoking [5]. Other risk factors for COPD include:
- Air pollution exposure - Secondhand smoke - History of childhood respiratory infections - Diet: dietary fiber intake is inversely related to COPD incidence [6]
A study published in the medical journal Gut in 2022 described the role of gut microbiota in COPD [7]. The study highlighted that dysbiosis (alteration of the gut microbiota) plays a role in influencing the pathogenesis of COPD. An increased abundance of Lachnospiraceae species in COPD patients may have contributed to chronic inflammation and worsening COPD. An increase in Lachnospiraceae species has also been observed in other chronic inflammatory diseases such as inflammatory bowel disease (IBD) [7].
The lung microbiota is known to play key roles in COPD [8]. Gut dysbiosis leads to increased gut permeability, leaking toxins and bacteria into the bloodstream which travel to the lungs, causing lung dysbiosis and possibly worsening COPD [8]. Increased gut permeability also leads to chronic systemic inflammation which worsens COPD.
For prebiotics which are dietary fibers, they also support healthy lung functions. By modifying our diets and increasing our intake of prebiotic fiber, we can potentially decrease our risk of COPD.
Prebiotics are food for our good gut bacteria. By supplementing our diets with prebiotics, we allow good gut bacteria to grow, and in turn crowd out bad ones. This establishes a healthy and balanced gut microbiota which helps support our respiratory health.
Good gut bacteria feeding on prebiotics also produce metabolites such as short-chain fatty acids (SCFAs) that confer health benefits. SCFAs are known to have anti-inflammatory effects and thus have the potential to reduce the risk of COPD [9].
The existence of the gut-lung axis suggests that improving our gut health supports our respiratory system and can potentially reduce the risk of lung diseases such as COPD. The use of prebiotics to induce positive changes to our gut microbiota and improve our gut health is one option we can consider to improve our respiratory health and reduce the risk of COPD.
Introduction to the Gut-Lung Axis
Prebiotic: Gut Microbiota, Gut Health, and Beyond
- Recent studies have suggested the importance of our gut health and microbiota in lowering the risk of stroke.
- Alterations in gut microbiota compositions have been found in patients with stroke as compared to healthy individuals.
- Our gut health and microbiota also play important roles during post-stroke recovery by modulating several key parameters such as immune response, blood pressure, and blood sugar.
- The use of prebiotics to induce positive changes to our gut microbiota and improve our gut health is one option we can consider to reduce the risk factors for stroke.
Stroke is a disease that affects the cerebral arteries that supply blood to the brain [1]. It occurs when the blood and oxygen supply to the brain gets disrupted. This can happen due to a blood clot (ischemic stroke) or when the blood vessels rupture (hemorrhagic stroke) [1]. According to the U.S. Centers for Disease Control and Prevention (CDC), more than 795,000 people in the U.S. suffer from stroke every year [2].
Recent studies have suggested the importance of our gut health and microbiota in lowering the risk of stroke. World Stroke Day is held on 29 October every year to help raise awareness about this public health emergency [3]. Read on to learn more about how gut health and microbiota may affect stroke and post-stroke management, as well as how they can potentially be new modifiable risk factors for stroke.
Optimum gut health means having the right balance of good gut microbes and bad ones in our gut. This composition of microorganisms in our gut is collectively termed gut microbiota. Our gut consists of trillions of such microorganisms, including bacteria, viruses, fungi and protozoa species. This set of gut microbiota is unique to everyone at birth and changes during the course of your life due to several factors including environmental, lifestyle, dietary habits, and consumption of medications such as antibiotics [4].
The innate set of gut microbiota (the set that we are born with) is thought to be the most optimum for oneself. This optimum composition deteriorates as we age. Along with poorer modern-day diets lacking in prebiotics (i.e., food for the beneficial gut bacteria) as well as increased use of medications, the composition and amount of good gut bacteria decrease even faster.
Dysbiosis refers to an alteration of the gut microbiota. Poor gut health and dysbiosis have been found to negatively affect risk factors for stroke such as blood pressure [5], sugar [6] and cholesterol [7] levels. This can potentially lead to an increased risk of stroke.
Apart from mitigating risk factors for stroke, our gut health and microbiota may be directly related to stroke.
Dysbiosis is not only associated with poorer control of metabolic markers like blood pressure, sugar and cholesterol. Such alterations in gut microbiota compositions have also been found in patients with stroke as compared to healthy individuals. A study presented at the European Stroke Organisation Conference (ESOC 2022) identified certain types of bacteria such as Negativibacillus and Lentisphaeria that were associated with a more severe stroke in the acute phase [8].
Beneficial gut bacterial species feed on prebiotics in a fermentation process. This process produces metabolites such as short-chain fatty acids (SCFAs). SCFAs can regulate inflammation, blood pressure and sugar, which are all important risk factors for stroke. These metabolites have also been found to be in lower levels in patients with ischemic stroke as compared to healthy individuals [9].
Our gut health and microbiota also play important roles during post-stroke recovery by modulating several key parameters:
- Immune response: SCFAs produced from the fermentation of prebiotics can stimulate immune cells that are key factors in favorable stroke outcomes [10]. - Blood pressure: certain strains of beneficial gut bacteria have been identified to be associated with lowered blood pressure levels [11]. - Blood sugar: healthy gut microbiota and SCFAs can assist in blood sugar metabolism and homeostasis, including the cellular uptake of sugar and thus reducing blood sugar levels [6].
There is accumulating research showing the importance of gut health and microbiota in affecting the risk of stroke. Dysbiosis is associated with stroke and several risk factors of stroke such as blood pressure, sugar and cholesterol levels as well. The use of prebiotics to induce positive changes to our gut microbiota and improve our gut health is one option we can consider to reduce the risk factors for stroke.
This article is written in conjunction with World Stroke Day, which falls on 29 Oct every year.
How Does Our Gut Health Affect Our Cardiovascular System?
Good Gut Health Is Linked To Lower Cholesterol Levels
Gut Microbiota and Its Implications in Diabetes and Blood Sugar
- 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.
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.
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].
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 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
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.
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
- According to a study by the Environmental Working Group, a total of 287 industrial chemicals were found in 10 newborn babies. Coupled with a decline in nutritional quality of a child's diet, there has been an increased incidence of childhood diseases.
- Our gut is home to trillions of microorganisms known as the gut microbiota.
- Gut health is linked to a child's development in at least 4 ways: physical growth, nervous system growth, immune system growth, and respiratory system growth.
- It is crucial we maintain a healthy balance of beneficial gut bacteria which may be achieved through taking prebiotics.
The presence of high levels of toxins in the modern world can adversely affect the development of fetuses and children. The umbilical cord provides for nutrients for the growth of the fetus in a mother’s womb. However, at the same time, it also carries chemicals and pollutants from the modern day’s environment. According to a study by the Environmental Working Group, a total of 287 industrial chemicals were found in 10 newborn babies [1]. Coupled with the decline in nutritional quality of a child’s diet, there has been an increase in the incidences of chronic diseases such as eczema, obesity and several types of infections [2].
Other than improving the diet of our children in this modern-day environment, the role of supplementation cannot be undermined. Various supplements such as prebiotics can help to improve our gut health by enhancing the growth of beneficial gut bacteria. Our gut is also linked to various other body systems such as the brain via the gut-brain axis, and the central nervous system [3]. How can we utilize this benefit and promote healthy growth and development for your children? Read on the find out more.
Our gut comprises of trillions of microorganisms. This unique set of microorganisms harbored within the gut is also commonly referred to as the gut microbiota (or gut microbiome). It comprises of various species ranging from bacterial, to viral, to fungal species. A healthy gut comprises a set of microorganisms that are largely beneficial to our health (e.g., Lactobacillus and Bifidobacterium spp.), minimizing the species that are detrimental to our health [4].
The innate set of gut microbiota is thought to be the most suitable and optimum for oneself and it starts developing as early as when the fetus is in the mother’s womb [5]. This optimum composition deteriorates as we age. Along with poorer modern-day diets lacking in prebiotics (i.e., food for the beneficial gut bacteria) as well as increased use of medications such as antibiotics, the composition and amount of good gut bacteria decrease even faster. This would lead to poorer gut health which may lead to negative effects such as constipation, unhealthy blood pressure [6], sugar [7] and cholesterol levels [8], as well as poor cardiovascular [9], respiratory [10] and immune health [11].
A child’s development can be divided into 4 distinct phases: infancy, preschool, middle childhood, and adolescence. Any divergence from certain developmental milestones could be a signal for disease such as obesity, allergies, or asthma [12]. The gut microbiota of a child can be affected by the following:
- Mode of delivery: infant delivered vaginally will have colonization which is represented by the mother’s vaginal tract. An infant who is delivered via caesarean section will more likely have colonization by maternal skin and oral microbes [13]. - Infant diet: breast-fed infants have microbiota mainly consisting of Lactobacillus and Bifidobacterium spp. Formula-fed infants’ gut microbiota are more likely to contain species like Clostridium [14].
The infants’ gut microbiota will mature into a more complex one that resembles an adult-like gut microbiota after the first year of life. Use of medications such as antibiotics can also affect the composition and amount of gut microbiota. Read on to find out how the gut microbiota of a child will affect the different elements of his or her general development.
1. Body growth
The gut microbiota plays a role in the general physical growth by affecting nutrients absorption and growth hormone signaling. A disruption in the gut microbiota can affect the infant’s weight. Studies have been done to examine the effects of gut microbiota on malnutrition and poor growth. Fecal matter of malnourished twins was transplanted into mice and subsequently developed weight loss and metabolic changes [15]. A separate study in Bangladesh children also shown significantly altered gut microbiota composition in children with malnutrition [16].
These studies done point to the possibility that the gut microbiota plays an important role in affecting the general physical growth of an infant, on top of dietary modifications.
2. Central Nervous System (CNS) growth
The brain and the gut communicate bidirectionally through the gut-brain axis. Research in mice have found that a normal gut microbiota can affect normal brain development as well as behavioral functions [17]. In studies involving humans, the alteration of gut microbiota (i.e., dysbiosis) was also associated with neurodevelopmental issues such as attention deficit hyperactivity disorder (ADHD) [18].
Dysbiosis can result in changes in the metabolite profiles, which then affects the bidirectional communication with the CNS.
3. Immune system growth
During the infants’ developmental stages, the immune system and gut microbiome are co-dependent on each other. The gut microbiota often acts as the first line of defense against pathogens by activating the infant’s innate immunity. The gut microbiota is also involved in production and differentiation of certain immune cells such as the T cells [19]. Other immunological diseases such asthma and allergies may also be associated with changes in the gut microbiota [12].
4. Respiratory system growth
Other than the gut-brain and gut-immune axis, there are also studies which demonstrated the existence of a gut-lung axis. This communication involving the gut microbiota and lung microbiota plays a role not just in gastrointestinal functions but also in lung immunity [10]. Dysbiosis has been associated with respiratory diseases such as asthma, one of the most common childhood diseases [20]. Metabolites produced by the healthy gut microbiota through fermenting prebiotics may also have anti-inflammatory effects in the lungs [21].
5. Other ways gut health affects the child
Although not directly involved in the development of these organs and systems in the infancy stage, the gut microbiota has profound effects in these areas as the infant and child grows up:
- Cardiovascular system [22] - Metabolic system: blood pressure, blood sugar and blood cholesterol levels [6-8]
The gut microbiota can act as a central regulator for metabolism. As the gut microbiota develops rapidly in the early years of one’s life, it is crucial to ensure optimum health of our gut microbiota to prevent such long-term cardiovascular and metabolic complications that may arise due to a poor balance of gut microbiota [23].
The importance of gut health in the healthy growth and development of a child cannot be undermined. With gut health and the gut microbiota having effects around most of the body systems’ development, it is crucial we maintain a healthy balance of beneficial gut bacteria. This may be achieved through taking prebiotics to enhance the growth of the good gut microbiota.
Gut-Brain-Immune Axis: An Introduction
Prebiotic: Gut Microbiota, Gut Health, and Beyond
- It is estimated that about 12% of American adults have high cholesterol levels.
- There are 2 main ways in which cholesterol can be obtained: exogenous and endogenous.
- Our gut microbiota may be able to alter blood cholesterol levels through several mechanisms.
- Several studies have also shown that prebiotics (which are selectively utilized by the beneficial gut bacteria) are able to lower cholesterol levels via several mechanisms.
Cholesterol is a key component in many cellular structures such as the cell membranes and a precursor to hormones such as steroids in the body. It is widely understood that high levels of it (i.e., hypercholesterolemia) are linked to atherosclerosis (i.e., building up of plagues in the blood vessels) [1] and cardiovascular diseases such as heart attacks and strokes [2]. It is estimated that about 12% of American adults have high cholesterol levels [3].
Cholesterol in the human body is being carried through the blood by proteins called lipoproteins. These proteins can be generally classified into 2 types [4]:
- High-Density Lipoprotein cholesterol (HDLc) (the ‘good’ cholesterol) - Low-Density Lipoprotein cholesterol (LDLc) (the ‘bad’ cholesterol)
There are 2 main ways in which cholesterol can be obtained [5]:
- Exogenous: dietary uptake, which accounts for about a quarter of total cholesterol - Endogenous: produced within the body by the liver
The health of our gut is largely dependent on the health of our gut microbiota, which is the unique collection of microbes residing in our gut. Recent studies have shown that the health of our gut is linked to cholesterol levels. Find out more about their associations and what can be done to improve our gut health and gut microbiota.
Our gut consists of trillions of microorganisms (or microbes), termed as the gut microbiota. These microorganisms can be bacteria, virus, and fungi. This set of microorganisms in our gut is unique to everyone, depending on several factors such as environmental, lifestyle, dietary habits, and antibiotics consumption [6]. This set of microbes feed on prebiotics to form metabolites such as short-chain fatty acids (SCFAs) and butyrate which confers health benefits to us, which include healthy blood sugar [7], blood pressure [8], immune health [9], and many more.
The innate set of gut microbiota 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 (i.e., food for the good gut bacteria) and increased consumption of antibiotics.
Studies have shown that the gut microbiota may be able to alter blood cholesterol levels, through their role in bile acid metabolism. Both sources of cholesterol pass through the gut, which implies that the gut microbiota may have effects on its levels [10].
Previous research in mice have shown that gut bacteria is able to metabolize cholesterol into a compound called coprostanol, which can aid in reducing cholesterol absorption and blood cholesterol levels [11]. This has also been reflected in recent human studies, which showed that subjects with coprostanol-forming microbes have lower blood cholesterol levels [12].
Another study done in mice also had similar results. Investigators wiped out the gut microbiota of mice using several antibiotics, and they found out that blood cholesterol level was 55% higher than mice who did not had their gut microbiota wiped out [13]. The authors concluded that this phenomenon occurred due to the gut microbiota influencing cholesterol homeostasis and metabolism, including synthesis by the liver [13].
SCFAs are also produced by the gut microbiota because of fermentation of prebiotics (e.g., resistant starch, dietary fibers). High SCFA concentration in the colon can impact microbial communities, inhibiting growth of bad bacteria (such as Salmonella) and promoting growth of beneficial bacteria (such as Lactobacilli and Bifidobacteria), which have been known to reduce risk of cardiovascular diseases [5]. Such SCFAs including propionate and butyrate also have the potential to lower cholesterol synthesis, hence reducing levels in the blood [14].
Prebiotic has been officially defined by the International Scientific Association for Probiotics and Prebiotics (ISAPP) as ‘a substrate that is selectively utilized by host microorganisms conferring a health benefit’ [15]. In simple terms, they are food for the beneficial gut bacteria, as they are resistant to digestion from the body’s enzymes and travel down to the colon largely intact.
Several studies have also shown that prebiotics such as inulin are able to reduce the formation of atherosclerotic plagues in mice [16]. It has also been theorized that prebiotics are able to lower cholesterol levels via 2 mechanisms [17]:
- Decreasing cholesterol absorption and increasing excretion - Indirect effect: producing SCFAs by the gut microbiota, resulting in positive effects on cholesterol metabolism (as described above)
Although there are medications like statins to lower cholesterol, it is important to also use non-pharmacological methods to maximize outcomes. Other than the usual ways of adopting healthy habits such as engaging in physical activity and losing weight, improving our gut health to promote the growth of beneficial gut bacteria may be another viable way.
Prebiotics encourage the healthy balance of your unique set of resident gut microbiota, creating an environment whereby beneficial bacteria flourish and crowd out unwanted bacteria. This can help in 2 ways:
- Growth of innate healthy and beneficial gut bacteria - Enhances effects of probiotics supplements, by allowing the beneficial strains to feed on them and increase their chances of survival and proliferate in the colon
Take foods that are rich in prebiotics, including onions, garlics, and wholegrains. If your diet is consistently lacking in such foods, you may also consider adding prebiotic supplements to your food and/or beverages to obtain your daily requirement of prebiotics.
Although high cholesterol does not show any symptoms on its own, it is a huge risk factor for cardiovascular conditions like heart attacks and stroke, which accounts for one of the highest causes of disease and death in many parts of the world. The health of your gut and gut microbiota has been shown to be associated with lower levels of blood cholesterol. One way to improve the health of your gut microbiota is through prebiotics, which encourages the healthy balance of our microbes in our gut.
Gut Health and Blood Pressure (Hypertension): How Are They Related?
Prebiotic: Gut Microbiota, Gut Health, and Beyond
- Our gut consists of different types of microorganisms, including bacteria, fungi, and viruses, and this composition is unique to everyone. The gut microbiota also works and communicates with other systems such as the immune system and the central nervous system (including the brain), termed as the gut-brain-immune axis.
- The gut and brain communicate bi-directionally via several pathways, including endocrinological, neurological, and immunological.
- Consumption of dietary fiber and prebiotics promotes diverse microbiota growth and are also important in providing substrates for the gut microbiota to form metabolites, which confer health benefits to us and thus improve the gut-brain axis.
The human’s gut consists of a certain composition of beneficial microorganisms that is unique to every individual, which is also known as the gut microbiota. On top of the usual gastrointestinal processes such as digestion and absorption, this composition of microorganisms has also been found to play a significant role in several other functions and diseases that are otherwise seemingly unrelated to the gut. Why and how is this gut-brain-immune axis possible?
Read on to find out more about this fascinating interaction between the gastrointestinal system, central nervous system, and the immune system.
Before we try to understand this complex interaction of the gut-brain-immune axis, let’s first understand what the gut microbiota is, what it does, and what happens when there is a change in this composition.
The gut microbiota consists of different types of microorganisms, ranging from bacteria, fungi, and viruses [1]. This composition is unique to everyone due to the impact from multiple factors including environmental and lifestyle factors [2]. One of the functions of the gut microbiota is to break down indigestible substrates like dietary fibers and intestinal mucus, producing short-chain fatty acids (SCFAs) and gases in the large intestine. These SCFAs are associated with several health benefits, including metabolism, homeostasis, controlling gut hormones, and lower rates of obesity [3].
Other gastrointestinal functions of the gut microbiota include the synthesis and absorption of vitamins and nutrients such as vitamin K and vitamin B, as well as maintain the integrity and structure of the gut barrier [4].
A change in the composition of the gut microbiota can happen due to several factors, including drugs (e.g., excessive use of antibiotics), toxins and pathogens [5]. This is also called ‘dysbiosis’, and this affects the permeability of the gut’s barriers.
Other than the effects the gut microbiota have on the gastrointestinal system, it also works and communicates with other systems such as the immune system and the central nervous system (including the brain).
The immune system is especially connected with our gastrointestinal system, as evidenced from the fact that more than 70% of immune cells are found in the gut [6]. The interactions between the gut microbiota and the immune system are thought to be via the SCFAs that are produced as by-products of the indigestible substrates (e.g., dietary fibers) [7]. These SCFAs are involved in the homeostasis of immune cells through several receptors [8], and act as key metabolites for the functioning of the intestinal surface layer. The intestinal surface layer, where the gut microbiota resides, also acts as a first line of defense for the body against incoming pathogens.
The gut microbiota also has a bidirectional communication with the central nervous system (CNS), including the brain. This interaction is often coined as the ‘gut-brain axis’. For one, the gut is physically connected to the nervous system and the brain via the vagus nerve. It is thought that the interaction between the gut and brain also otherwise happens via several pathways [9]:
Neurological
SCFAs such as butyrate (produced by the gut microbiota by breaking down dietary fiber) also affect CNS functions such as the formation of the blood brain barrier (BBB) [10], which shields the brain from toxic substances and filters chemicals to the blood [11].
Endocrinological
Chemicals that can affect brain cell physiology (i.e., neurotransmitters) are produced by some of the species within the gut microbiota [2]. One such neurotransmitter is serotonin, which also plays a part in affecting an individual’s mood.
Immunological
Gut microbiota also affects mucosal immune activation. An increase in inflammation was seen in studies involving mice after they were treated with oral antibiotics [9]. It is thought that this activation may be due to enzymes such as proteases [9].
Dysbiosis (i.e., alteration in the gut microbiota) is also associated with many hosts diseases, including diseases related and not related to the gastrointestinal system. Some of these includes [5]:
- Gastrointestinal system: irritable bowel syndrome (IBS), inflammatory bowel diseases (IBD) - Other body systems: asthma, allergies, obesity, cardiovascular diseases
The role of supplementation to improve the gut health is not only important for the gut’s health but is also paramount for the development of other crucial systems such as the immune system and nervous systems. As mentioned in this article, dysbiosis has also been associated with several diseases, including even autism via the gut-brain axis [13]. Hence, developing the gut microbiota is an important thing to do that should not be missed out.
Consumption of dietary fiber and prebiotics promotes diverse microbiota growth [14]. Other than promoting for microbial growth, dietary fibers are also important in providing substrates for the gut microbiota to form SCFAs, which have been found to be beneficial in multiple functions and developments as described above in this article.
Another consideration may be the excessive use of antibiotics in children, which has been associated with dysbiosis as well. Antibiotics use has also been linked with several diseases such as asthma and juvenile arthritis [15]. Parents should also not request for antibiotics use excessively and unnecessarily for their children to prevent possible dysbiosis as well.
The benefits of a healthy gut extend beyond the gastrointestinal system. Healthy gut microbiota has also been thought to have beneficial effects on the health of other systems, particularly the immune and nervous systems. Consider better nutrition and supplementations to improve our gut health, which have beneficial effects extending beyond that and into the nervous and immune systems.
Prebiotic: Gut Microbiota, Gut Health, and Beyond
Gut Health and Inflammatory Bowel Disease (IBD)
Irritable Bowel Syndrome (IBS): Types, Symptoms, and Treatment
- An estimated 3 million adults in the United States suffer from Inflammatory Bowel Disease (IBD).
- The health of your gut and the gut microbiota has been shown to affect inflammation, which is the key feature of IBD.
- Dysbiosis has been observed in patients with IBD as compared to healthy individuals.
- The Anti-inflammatory Diet for IBD (IBD-AID), which includes the use of more prebiotic and probiotic foods to restore the healthy levels of gut microbiota, has been researched and studied as an adjunct therapy for IBD treatment.
Inflammatory Bowel Disease (IBD) is a chronic inflammatory disease of the gut and bowels. The 2 conditions that are commonly associated with IBD are Crohn’s disease (CD) and ulcerative colitis (UC). The differences between CD and UC lie in the following [1]:
- Location: inflammation can affect any part of the gastrointestinal (GI) tract for CD; for UC, it is limited to the colon and the rectum - Type: damaged tissues appear in patches in CD, whereas the damaged areas are often continuous in UC - Extend: the extend of inflammation can affect multiple layers of the GI tract in CD, while inflammation is only often present in the innermost layer of the colon in UC.
An estimated 3 million adults from the United States (U.S.) suffer from IBD [2], with many more children under the age of 18 years old being diagnosed as well [3]. Common symptoms of IBD may resemble irritable bowel syndrome (IBS), but they are not the same condition. Some symptoms include abdominal pain, weight loss, and rectal bleeding.
The health of your gut and the gut microbiota (also called gut microbiome) has been shown to affect inflammation, which is the key feature of IBD [4]. Fiber intake may also have certain roles in the cause of IBD, which includes (but not limited to) its effects as a prebiotic for the gut microbiota.
World IBD Day falls on 19 May every year [5]. In conjunction with this day, find out how the health of your gut (including your gut microbiota) is related and associated with this autoimmune and inflammatory disease of the bowels!
The human digestive system and health is greatly affected by the microorganisms harbored within the gut, which includes bacteria, virus, and fungi species. This is termed as the gut microbiota, with the number of bacterial cells estimated to be more than 10 times the number of human cells [6]. Its composition is unique to everyone, as several factors such as environmental and lifestyle contribute to the uniqueness of the gut microbiota composition [7].
Indications of an unhealthy digestive system can range from local (i.e., gut-related) such as digestive issues, to more systemic-related problems like skin health, mood swings, and even depression [8], and many of these effects may be contributed by the gut microbiota [9]. A change in the bacterial species and environment could happen because of drugs (e.g., antibiotics), toxins, and pathogens. This is called ‘dysbiosis’ [10].
There have been several published reports that studied the effects of the gut microbiota on IBD, mainly reflected by the gut microbiota’s effect on reducing inflammation.
Dysbiosis has been observed in patients with IBD as compared to healthy individuals [11]. As a healthy gut microbiota has been associated with anti-inflammatory effects on the gut, dysbiosis could have pro-inflammatory effects on the gut, leading to symptoms of IBD. An increase in the number of ‘bad’ bacteria in the gut also affects the gut in other ways, such as changing the permeability of the intestine walls [11]. This effect has also been shown in animal studies, where rats with gut microbiota changes induced by using antibiotics were associated with recurrent gut inflammation [12].
The gut microbiota also produces short-chain fatty acids (SCFAs) through the fermentation of prebiotics such as dietary fiber [9]. The concentrations of these SCFAs were also found to be lower in IBD patients, which may also play a part in inducing inflammation, leading to IBD and its respective symptoms [11].
Dietary changes that target gut microbiota may help to alleviate IBD symptoms [13]. The Anti-inflammatory Diet for IBD (IBD-AID) has been researched and studied as an adjunct therapy for IBD treatment [14]. The IBD-AID includes the use of more prebiotic and probiotic foods to restore the healthy levels of gut microbiota. According to the study, a 61.3% of patients on IBD-AID for 8 weeks reported a significant decrease in IBD symptoms [14]. IBD-AID also emphasize on the importance of using soluble fiber, which also promotes benefits such as SCFAs production by the gut microbiota, as mentioned above as well [15].
Prebiotics are substrates that are used and broken down by the gut microbiota to form metabolites such as SCFAs. Different forms of prebiotics include [16]:
- Resistant starches such as Fibrosol Prebiotic - Frutans - Galacto-oligosaccharides - Pectin
Inflammatory Bowel Disease (IBD) is a chronic inflammatory disease that can affect any part of the gastrointestinal system, depending on the type of IBD. The gut microbiota and alterations of the composition of it has been associated with IBD, as dysbiosis has been shown to be observed in patients with IBD as compared to healthy individuals. Dietary changes such as increasing the usage of prebiotic and soluble fiber may be useful in alleviating the symptoms of IBD.
This article is written in conjunction with World IBD Day, which falls on 19 May every year.
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- In 2021, the World Health Organization (WHO) has reported that around 1.28 billion adults aged 30-79 years worldwide have hypertension.
- The use of fiber to reduce blood pressure has been studied and published in various clinical trials.
- The effects of fiber on blood pressure lowering may have also been due to the gut microbiota. The gut microbiota ferments the undigested fiber (acting as prebiotics) that passes through to the large intestine, producing short-chain fatty acids (SCFAs) which activate receptors that play a part in blood pressure regulations.
- Other mechanisms include the regulation of genes related to immunity, inflammation and metabolism which may also affect blood pressure.
Hypertension, or high blood pressure, is an increasingly prevalent condition worldwide. In 2021, the World Health Organization (WHO) has reported that around 1.28 billion adults aged 30-79 years worldwide have hypertension, and less than half have it diagnosed and treated [1]. Some complications of high blood pressure include cardiovascular diseases such as heart attacks and strokes [1]. Often dubbed as the ‘silent killer’, this condition often shows no signs and symptoms [1].
Blood pressure reading is mainly divided into 2 numbers [2]:
- Systolic blood pressure (i.e., the top number): this number indicates the pressure your blood is exerting against the blood vessels’ walls when the heart beats - Diastolic blood pressure (i.e., the bottom number): this number indicates the pressure your blood is exerting against the blood vessels’ walls when the heart relaxes between beats
With the incidence of hypertension on the rise, there is also an increasing awareness of how diet and other means can help with lowering the blood pressure naturally (i.e., without the use of medications). The implications of using dietary fiber and their effects on blood pressure has garnered interest [3]. How does the use of dietary fiber help with lowering blood pressure? Does the fiber affect blood pressure directly or through other mechanisms, such as via its interactions with the gut microbiota?
World Hypertension Day falls on 17 May every year. In conjunction with this day, find out how the health of your gut and dietary fiber intake is implicated in your blood pressure readings!
Fiber is a form of carbohydrates, naturally present in plants. Although most carbohydrates can be broken down by the body’s enzyme into simple sugars, our body is unable to completely break down fibers and gets passed through to the large intestine. It is generally divided into 2 forms: soluble and insoluble fibers [4].
The use of fiber to reduce blood pressure has been studied and published in various clinical trials. A meta-analysis done in 2005 aggregated data from 24 different studies and trials to see the effects of fiber on blood pressure [5]. This study found that fiber supplementation at 11.5g per day caused a non-significant decrease in systolic blood pressure and a significant change in diastolic blood pressure, with effects larger for older and hypertensive populations [5].
The authors of the study also concluded that increasing fiber intake in the general population may contribute to prevention of hypertension [5], especially as the intake of dietary fiber in the general population is low [6]. A high-fiber diet was also found to have experienced a 15% reduction in systolic blood pressure, along with an inverse risk of developing cardiovascular diseases [7].
The effects of fiber on blood pressure lowering may have also been due to the presence of the microorganism environment in the gut, which is also termed as your gut microbiota. The gut microbiota consists of a range of microorganisms consisting of bacteria, virus, and fungi [8], and the composition differs depending on several factors such as environmental and lifestyle reasons (e.g., diet) [9].
The gut microbiota ferments the undigested fiber that passes through to the large intestine, producing short-chain fatty acids (SCFAs) and gases. These SCFAs produced by the breakdown of fiber by the gut microbiota play important roles in multiple body functions, one of which includes the modulation of blood pressure and decreasing the risk of developing hypertension from a fiber-rich diet [10]. Dysbiosis of the gut (i.e., alterations of the gut microbiota) is also found to be linked with hypertension [11].
There are many mechanisms on how the gut microbiota and its derivatives affect the blood pressure [12]:
- SCFAs produced from the fermentation of the fibers activates receptors that play a part in blood pressure regulations - Reduction in microbial gene richness may also lead to inflammation, which can also be a cause of high blood pressure - Gut microbiota can influence the production of chemicals by gastrointestinal cells, which has effects on the gut-brain axis - Gut microbiota may also regulate genes related to immunity, inflammation and metabolism which may also affect blood pressure
Hypertension, often termed as the ‘silent killer’, often presents with no symptoms, and affects more than 1 billion of adults worldwide. It has severe complications if it goes undetected and untreated, including heart attacks and strokes. There has been much interest in natural ways such as the use of diet and dietary fiber in managing and lowering blood pressure. The use of fiber has also been touted to be able to reduce blood pressure, with potential effects due to the gut microbiota. Importance of the gut microbiota on blood pressure could also have been mediated by other factors such as its effects on the immunity and metabolism of the individual.
This article is written in conjunction with World Hypertension Day, which falls on 17 May every year.
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