Introduction
Gut health is an important indicator of a healthy lifestyle. One of the key factors in the maintenance of gut health is the presence of several microorganisms. These organisms are not harmful; on the contrary, these microorganisms help to maintain several digestive functions. The population of such microorganisms is affected by several chronic diseases.
What Is Gut Microbiota?
The gut microbiota is present in the gut since birth. Around 500- 1000 species of microorganisms are present in the gut. According to some researchers, the number of gut microbiota may go upto 35000 species. The species of bacteria depends on the morphological site and the acidity of the gut. In the esophagus, where the pH is less than 4, species like Bacteroides, Gemella, Megasphaera, Pseudomonas, and Prevotella can be seen. Streptococcus, Lactobacillus, Prevotella, Enterococcus, and Helicobacter pylori can be seen in the stomach, where the pH is around 2. Species like Clostridium, Prevotella, Porphyromonas, Eubacterium, Ruminococcus, Streptococcus species, Enterobacterium, and Enterococcus, Lactobacillus species can be observed in the colon. In the small intestine, where the pH is between 5 to 7, microorganisms like Bacteroides, Clostridium, Streptococcus, and Lactobacillus can be found. Lachnospira , Roseburia, Butyrivibrio, Ruminococcus,and Fecalibacterium can be found in the cecum.
Several factors like illness, antibiotic treatment, and diet are responsible for developing different microbiota in children. Also, factors like other delivery methods are associated with the differentiation of gut microbiota.
The functions of the gut microbiota are:
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Dietary fibers are digested and fermented with the help of gut microorganisms. Bacteroides, Roseburia, Bifidobacterium, Fecalibacterium, and Enterobacteria help in this procedure.
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The gut microbiota produces short-chain fatty acids and gases. This process produces substances like acetate, propionate, and butyrate.
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Butyrate acts as one of the main energy sources of the colonocyte cells. This maintains various morphological functions like beta-oxidation of the oxygen. This process regulates the bacterial population in the gut. This also prevents the accumulation of toxic metabolic byproducts.
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Gluconeogenesis is maintained by propionate.
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De novo synthesis of vitamins is influenced by the action of the gut microbiota. Lactic acid bacterias are essential for the synthesis of vitamin B12. Bifidobacteria is responsible for the synthesis of folate. This is useful for maintaining metabolic processes and DNA synthesis and repair. Other vitamins like vitamin K, biotin, and riboflavin are also synthesized with the help of the gut microbiota.
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The chances of oxalate stone formation in the kidney are reduced by the action of gut microorganisms. Microorganisms like Oxalobacter formigenes, Lactobacillus species, and Bifidobacterium are responsible for the destruction of the oxalate produced during the fermentation of the carbohydrate.
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These microorganisms are helpful in the protein metabolisms that are essential in the formation of several signaling molecules.
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The breakdown of the polyphenols is controlled by the gut microorganisms. This process helps in the formation of active components of polyphenols. These compounds are absorbed into the portal vein and reach the targeted organs. Such active polyphenols provide antimicrobial action.
What Is Gut Dysbiosis?
The loss of beneficial microorganisms in the gut is known as gut dysbiosis. In this condition, a reduction in the number of gut bacteria, along with a reduction in the number of variations of the microorganisms, can be seen. The factors that are responsible for gut dysbiosis are:
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The amount and characteristics of the gut micro bacteria depend upon the diet. Significant differences in the amount of gut bacteria can be seen in breast milk and formula-fed infants. A high amount of dietary vegetables, fruits, and fibers in the diet is linked to richness in the gut microflora. Animal-based diet is responsible for a decrease in gut microflora like Firmicutes, Alistipes species, and Bacteroides species. On the other hand, a carbohydrate-rich diet is associated with an increased number of microorganisms like Ruminococcus bromii, Roseburia, and Eubacterium rectale.
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Infections and inflammations are other causative factors that are associated with the change in the population of microorganisms. Factors like bactericidal fluids produced by the gastric glands and live and antimicrobial molecules like defensins and lysozymes are responsible for such changes. In recent times COVID-19 infection has been linked to changes in the population of microflora.
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Disruption of the gut microbiota ecosystem is another essential factor in gut dysbiosis. Host factors and altered immune responses of the person may be responsible for the disruption of the gut barrier. Modification of the genes like ATG16L1 and NOD2 are associated with gut dysbiosis.
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One of the main causes of alteration of the gut microflora is antibiotic treatment. Broad-spectrum antibiotics are associated with a reduction in the number of gut microorganisms.
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Lifestyle factors play a crucial role in the gut dysbiosis. Factors like psychological stress and chronic alcoholism are associated with gut dysbiosis.
What Is the Relationship Between Gut Dysbiosis and Chronic Diseases?
Several systemic and chronic diseases are linked to gut dysbiosis. These diseases are:
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Irritable bowel syndrome (IBS) is a gut disorder characterized by pain in the abdomen, altered bowel movement, and excessive gas formation. A clear difference in the population of microorganisms can be between normal people and patients suffering from irritable bowel syndrome (IBS). In such patients, a reduction in the number of Bifidobacterium and Faecalibacterium species can be seen. On the other hand, an increase in the number of microorganisms like Ruminococcus, Clostridium, and Dorea can be observed.
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Inflammatory bowel disease (IBD) is a long-lasting inflammatory disorder of the digestive system. In such conditions, chronic ulceration in the digestive tract can be seen. In certain cases, it is linked to ulcerative colitis and Crohn’s disease. In such conditions decrease in the number of Ruminococcaceae and Lachnospiraceae species can be seen. A reduction in the number of such bacteria is linked to a decrease in the production of butyrate. This is responsible for the reduction in the amount of short-chain fatty acid production.
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Atopic eczema is a chronic skin disorder that mainly affects young individuals. Change in the immune response is one of the key causes of such a disorder. In such conditions, a decrease in the number of microorganisms like Bifidobacteria, Bacteroidetes, and Bacteroides can be seen. An increase in the number of harmful organisms like Clostridia and Escherichia coli can be seen.
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Type 2 diabetes is one of the prevalent medical conditions. It is characterized by high blood sugar levels in the blood. Decreased number of gut microbiota like Bifidobacterium, Bacteroides, Faecalibacterium, Akkermansia, and Roseburia can be observed in such conditions. Butyrate-producing in such cases is impaired.
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Chronic kidney disease (CKD) is the gradual loss of kidney functions. In such patients, a reduction in the number of Bifidobacterium species, Lactobacillaceae, Bacteroidaceae, Akkermansia, and Prevotellaceae is observed. Also, the number of pathogenic microorganisms like Enterobacter, Klebsiella, and Escherichia can be seen.
What Are the Treatment Options?
The treatment of gut dysbiosis can be divided into two parts:
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Preventive Methods: Increased intake of dietary fibers is one of the main methods to prevent gut dysbiosis. About 10 grams of dietary fiber can improve gut health significantly.
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Prebiotics: These are the non-digestible oligosaccharides. Gut microorganisms ferment these substances and produce small-chain fatty acids. These, in turn, help in the improvement of gut health. Berberine, Curcumin, Quercetin, and Resveratrol are examples of prebiotics.
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Probiotics: The administration of microorganisms can be proven to be helpful in the improvement of gut health. Microorganisms like Lactobacillus casei, Lactobacillus planatarum, Lactobacillus bulgaricus, Lactobacillus acidophilus, and Bifidobacterium longum are administered as probiotics.
Conclusion
The human digestive system is the home of various microorganisms. Such microorganisms are helpful in the production of short-chain fatty acids. They also help to maintain the integrity of the gut epithelium. In various chronic diseases, the number of gut microorganisms is reduced. In certain cases, increases in the number of pathogenic microorganisms can also be seen. Prebiotics and probiotics are effective ways to treat gut dysbiosis.
