Introduction:
Human nutrition has evolved significantly during the last few decades. There has been a decline in fiber consumption and a rise in processed, high-fat, and high-calorie foods. In addition, there has been a rise in the population affected by inflammatory disorders. This requires external dietary intervention to restore healthy gut flora. Additionally, considering the potent immuno-modulatory properties of SCFAs (short-chain fatty acids), using prebiotics to produce metabolites generated from microbes is being investigated as a possible therapeutic and preventive approach for gut inflammation. Thus, research on prebiotics has increased dramatically.
What Is a Prebiotic?
A prebiotic is "a non-digestible food substance that selectively stimulates the growth or metabolism of a few types of bacteria in the colon, thereby improving host health and having a beneficial effect on the host." This definition remained nearly constant for almost 15 years.
Prebiotics are limited to a small number of carbohydrate group molecules, including lactulose, GOS (galacto-oligosaccharides), long and short-chain β-fructans [FOS (fructo-oligosaccharides) and inulin], and others. The 6th Meeting of the International Scientific Association of Probiotics and Prebiotics (ISAPP) in 2008 defined "dietary prebiotics" as "a selectively fermented ingredient that results in specific changes in the composition or activity of the gastrointestinal microbiota, thus conferring benefit(s) upon host health.".
A substance is categorized as a prebiotic based on the following standards.
It should:
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Be able to withstand the acidic pH of the stomach and be unable to undergo hydrolysis by mammalian enzymes.
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Be able to be processed by the intestinal microbiota.
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Be able to selectively stimulate the growth or metabolism of intestinal bacteria, thus improving the host's health.
What Is Gut Immunity?
The gut is separated into two segments: the upper and lower regions. The mouth, pharynx, esophagus, stomach, and duodenum are located in the upper region, and the small and large intestines are primarily in the lower region. The lower region contains most of the gut microbiota, highlighting the importance of the intestinal immune system. Gut-associated lymphoid tissue (GALT) and other cells make up the immune system and defend the gut from many antigens easily obtained from food, commensal bacteria, and pathogenic microorganisms.
A wide variety of intestinal cells are in charge of promoting the creation of IgA isotypes, which further strengthens gut immunity. The helper maintains the mucosal barrier T-cells 17 (Th17 cells). The enzymatic capacity of the host prevents the digestion of fiber carbohydrates, such as pectin, cellulose, beta-glucan, gums, and lignin, in the upper gastrointestinal tract.
But, these compounds are believed to be selectively fermented into SCFAs, specifically acetate, butyrate, propionate, and lactate, by resident bacteria in the colon. Most bacteria found in the colon are strict anaerobes that get their energy from fermentation. The gut microbiota's expression of several transport proteins and enzymes allows it to ferment fiber.
How Does Prebiotics Affect Gut Immunity?
Diet has the most direct and significant impact on the colonization of gut microbes. Food and the species found in the gut microbiota are closely associated. Food consumption may alter the composition of dominant species in the human gut microbiota, which could impact health.
Bacteroidetes and Firmicutes are the two most prevalent phyla in most healthy people. Through significant changes in gut microbiota composition and direct effects on the mucosal immune system, dietary fibers can function as potent prebiotics, improving the immune system and enhancing enteric inflammatory diseases.
Prebiotics can also promote resistance against pathogenic bacterial colonization by preventing pathogens from adhering to the intestinal epithelium. The control of the gut microbiota mediates the other health benefits of prebiotics, which include preventing diarrhea or constipation, improving lipid metabolism, and stimulating mineral adsorption.
What Are Some Prebiotic Foods?
Prebiotics are naturally occurring fibers found in vegetables, fruits, and legumes.
Some foods that are high in prebiotics are:
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Apples.
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Asparagus.
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Barley.
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Berries.
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Bananas.
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Burdock root.
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Chicory root.
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Konjac root.
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Cocoa.
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Dandelion greens.
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Jerusalem artichokes.
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Jicama.
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Garlic.
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Leeks.
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Legumes, beans, and peas.
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Oats.
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Onions.
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Seaweed.
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Wheat bran.
What Are the Benefits of Prebiotics?
Prebiotics have many advantages that extend beyond improved digestion. The gut's state impacts the body system and general health, whether healthy or ill.
Studies have indicated that prebiotics could:
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Boost metabolism and digestion.
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Aid in controlling bowel movements.
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Boost bone density and calcium absorption.
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Regulate insulin resistance and blood sugar levels.
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Promote the synthesis of hormones that help control appetite.
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Reduce inflammation in the body.
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Improve the immunological system.
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Aid in maintaining and balancing hormone levels.
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Decrease the risk of allergies.
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Reduce the risk of heart problems.
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Control emotions and lower stress hormone levels.
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Reducing the amount of cholesterol.
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Decreases the risk of colon cancer.
What Is Symbiotic Therapy?
Prebiotics could be given alongside living bacteria (probiotics) to use the maximum energy source, thereby improving the host's health. Symbiotics are the mutually beneficial mixtures of probiotics and prebiotics. Prebiotics, probiotics, and symbiotics are being investigated for their potential health advantages in various conditions due to their nature and safety.
It is important to remember that the advantages of controlling the gut microbiota to create intestinal homeostasis also apply to other host systems. A major amount of research is being conducted on the impact of prebiotics and probiotics on host behavior for several chronic diseases, including obesity, arthritis, diabetes, alcoholism, cancer, asthma, and cardiovascular disorders.
Conclusion:
Consumers widely accept health-promoting foods and components. Prebiotics have many advantages and are crucial for preserving the gut and enhancing general health. However, there are difficulties associated with adding probiotics and prebiotics to food or ingesting these functional food items directly as dietary supplements. These substances interact with ingested probiotics or gut microbes, and their highly varied structures still need to be fully understood. Therefore, further research has to be done to add prebiotics as a dietary supplement.
