Nutritional Modulation of the Gut Microbiome PDF

Nutritional modulation of the gut microbiome Asst. Prof. Dr. Ayhan MEHMETOĞLU [email protected] Learning objectives At the end of this lecture students need to know the followings: Gut Microbiota Overview Diet styles (Western, plant-based, high-fat, medical ketogenic, an...

Nutritional modulation of the gut microbiome Asst. Prof. Dr. Ayhan MEHMETOĞLU [email protected] Learning objectives At the end of this lecture students need to know the followings: Gut Microbiota Overview Diet styles (Western, plant-based, high-fat, medical ketogenic, and Mediterranean) Effect of each diet as a modulator of the gut microbiota Fiber and the Gut Microbiome Bacterial metabolites effect on inflammation and metabolic endotoxemia About Gut Microbiota There are 10 times the number of microbial cells in the human gut than in the whole human body Roughly 100 trillion microbes 5000 different species Weighing approximately 2 kg Gut microbiota composition includes bacteria, viruses, fungi, and parasites Furthermore, the main species of bacteria include Prevotella, Ruminococcus, Bacteroidetes, and Firmicutes https://www.gutmicrobiotaforhealth.com/the-knowns-and-unknowns-of-the-human-microbiome/ doi.org/10.3390/nu12010016  The ratio between the bacterial species Bacteroidetes and Firmicutes has been shown to play an important role in health and disease Importance of gut microbiome Bacteria within the gut microbiome are involved in harvesting energy from food, balancing the beneficial and opportunistic bacterial composition, and manufacturing neurotransmitters, such as serotonin, enzymes, and vitamins. For instance, vitamin K, which is produced from bacteria, is involved in both immune and metabolic functions. SO, when there is an imbalance in bacterial species, disease could result Diet effect on gut bacterial composition With diet noted to be one of the most powerful influences to alter the bacterial composition, a change in the diet composition can affect this ratio What is the role of diet on the gut microbiome and its implication for disease, specifically obesity and type II diabetes?  Diet is a main contributor to the alteration in gut microbiome diversity, both in the short term and the long term  Bacterial composition, as a result of diet, can be linked to certain diseases, specifically Bacterial diseases that arise due to chronic low-grade composition inflammation, such as type II diabetes. A diet that is high in animal protein increases and type II Bacteroides spp., Alistipes spp., and Bilophila diabetes spp., while it decreases the beneficial bacteria Lactobacillus spp., Roseburia spp., and E. rectale, affecting the bacterial diversity in the gut microbiome.  Effect of Animal-Based Diet on Gut Microbiome The typical “Western diet”, consisting of high-fat, high-sugar foods has also been linked to chronic low-grade inflammation, metabolic disease, and obesity.  Evidence from many studies show a correlation between a high-fat diet and gut microbiota changes; Bacteroidetes were reduced and Firmicutes were increased  Low-fat, high-fiber diets have the ability to alter the microbial intestinal composition in a positive manner. Effect of Plant- Shifting the microbiome environment towards the Based Diet on Gut beneficial bacteria Prevotella and Bacteroides. Microbiome Shifting away from Firmicutes.  European diet vs African diet A study that was conducted on children from Burkina Faso and Italy, examined the effect that diet has on bacterial composition. The European children consumed a diet that was similar to that of theWestern diet, being low in fiber, while the Burkina Faso children (African children) had a diet that was rich in fiber and resistant starch. Researchers found that the Burkina Faso children had a microbiome that was enriched with Bacteroidetes, and genus Prevotella and Xylanibacter, while being depleted of Firmicutes. The African children also had significantly more SCFA production when compared to the European children. Effect of Mediterranean Diet on Gut Microbiota The Mediterranean diet is plant focused, high in fiber and omega-3 fatty acids, and low in animal protein and saturated fat. Effect of Mediterranean Diet on Gut Microbiota It has been shown that adherence to this diet was found to be associated with increased levels of SCFA, Prevotella, and fiber-degrading Firmicutes. Researchers also found that the ratio of Prevotellato-Bacteroides was greater in those who adhere to the Mediterranean diet, indicating that a diet that is high in natural fiber and resistant starch positively alters the bacterial composition of human subjects  The Western diet consisted of lard, beef tallow, butter, egg, cholesterol, casein, lactalbumin, dextrin, high-fructose corn syrup, and sucrose while the Mediterranean diet was comprised of fish oil, olive oil, fish meal, butter, egg, black and garbanzo bean flour, wheat flour, juice, fruit puree, and sucrose Effect of Mediterranean diet Microbiome of people consuming the Mediterranean diet was significantly more diverse when compared to the microbiome of people consuming the Western diet. They also had a higher abundance of Lactobacillus, Clostridium, Faecalibacterium, and Oscillospira, and a lower abundance of Ruminococcus and Coprococcus. After a 3-month Mediterranean diet intervention, the subjects had a significant change in their gut microbiome composition, and had an abundance of Enterorhabdus, Lachnoclostridium, and Parabacteroides, with increased production of SCFAs. The diet also resulted in a reduction in the inflammatory cytokines. Fiber and the Gut Microbiome Fiber Dietary fiber refers to non-digestible carbohydrates and lignin that are intact and intrinsic in plants. Dietary fiber differs in chemical structure, water solubility, viscosity, and fermentability. Dietary fibers are carbohydrate polymers that contain three or more monomeric units that are resistant to digestive enzymes and are not hydrolyzed or absorbed in the small intestine. They are further broken down into the groups soluble fiber and insoluble fiber. Soluble fibers have been of much interest, due to them being metabolized by the gut bacteria and producing short-chain fatty acids (SCFA) Fiber effect on Gut Microbiome The bacterial species that are the most respondent to dietary fiber are those who belong to Firmicutes and Actinobacteria. High-fiber diets have been linked to an increase in SCFA production within the gut. Dietary fibers escape digestion and are metabolized by the bacterial flora within the gut microbiome, producing the SCFAs. When dietary fiber was in short supply SCFA production was reduced. Not only is SCFA production reduced when fiber intake is low, but it also causes the gut microbiota to utilize less-favorable substrates, such as amino acids and host mucins, for energy. Prebiotic Inulin https://www.nutrientsreview.com/carbs/soluble-fiber-inulin.html Effect of Prebiotic Inulin on gut microbiome Prebiotic inulin-type fructans affect the fecal bacteria and SCFA production in patients with type II diabetes. The inulin-type fructans resulted in moderate changes in the microbial composition of type II diabetics, with the bifidogenic effect being most prominent on Bifidobacterium adolescentis. Supplementation of inulin-type fructans resulted in a significant increase in bifidogenesis and total SCFA production Resistant Starch https://blog.myfitnesspal.com/the-important-role-resistant-starch-plays-in-weight-loss/ Effect of resistant starch on gut microbiome Resistant starch has long been an established food component that has received considerable attention for positively impacting the gut microbiota. Effects of a diet that was supplemented with resistant starch 1 (RS1 from native potato starch), or supplemented with resistant starch 2 (RS2 from modified potato starch). Both the RS1- and RS2-fed had an increase in Bifidobacterium spp. The RS2 group, however, also had an enhanced composition of lactobacilli, streptococci, and Enterobacteriaceae. The production of SCFA increased in both the groups when compare with the control group Phytochemicals and Their Effect on the Gut Microbiome Polyphenols and Flavonoid Polyphenols Polyphenols have been popularized in discussion, especially for the anti-cancer properties that they possess; however, recently they have been shown to have positive effects on the gut microbiome Flavonoid  Flavonoids are present in fruits, vegetables, legumes, nuts, and seeds. Flavonoids and their metabolites have been shown to exhibit positive gut-modulating properties, specifically on SCFA production and LPS reduction. Bacterial Metabolites Short-Chain Fatty Acids (SCFA) Effect on Bile Acids Inflammation Tryptophan and Metabolic Trimethylamine (Tma/Tmao) Endotoxemia Short- SCFA are bacterial metabolites derived as a result Chain of fermentation of dietary fibers by bacterial flora within the gut microbiome. Fatty Acids It has been established that dietary fiber promotes weight loss and an improvement in glycemic (SCFA) control; however, several recent studies have been conducted, to examine the relationship between dietary fiber fermentation, the production of SCFA, and improved metabolism Effects that SCFA have on the gut microbiome, and their role in reducing inflammation, improving insulin resistance, and promoting satiety  Bile acids (BA) are secreted into the gut lumen, in the presence of fat. There are two main types of primary bile acids, including (1) cholic acid and (2) chenodeoxycholic Bile Acids acid. Primary bile acids are transformed by the gut microbiota.  Indole derivatives and tryptamine have vital roles in the homeostasis of epithelial and immune cells in the gut These compounds are formed through Tryptophan tryptophan metabolism within the gut microbiome These metabolites have the potential to promote Th17 reprogramming to Treg cells, resulting in a decrease in inflammation  The typical Western diet is composed of a high consumption of red and processed meat, containing high levels of carnitine and choline, both of which are precursors for the gut bacteria to produce trimethylamine (TMA). Trimethylamine TMA, created mainly by the gut bacteria Firmicutes and proteobacteria, is transported (Tma/Tmao) to the liver, to be converted into trimethylamine N-oxide (TMAO). TMAO has been linked to inflammation and is shown to be associated with type II diabetes and obesity. Summary Summary References Sonnenburg JL, Bäckhed F. Diet-microbiota interactions as moderators of human metabolism. Nature. 2016 Jul 7;535(7610):56-64. doi: 10.1038/nature18846. PMID: 27383980; PMCID: PMC5991619. Beam A, Clinger E, Hao L. Effect of Diet and Dietary Components on the Composition of the Gut Microbiota. Nutrients. 2021 Aug 15;13(8):2795. doi: 10.3390/nu13082795. PMID: 34444955; PMCID: PMC8398149.  For any question [email protected] 43