Gut microflora or the human microbiome
Energy Balance, Immune Health and Digestion
Niche: A shallow recess, a place or position.
Our intestines harbor over five pounds of bacteria known as the gut microflora or microbiota. There are over 100 trillion microorganisms in our digestives tract, with 1,000 different microbial species, containing roughly 3.3 million genes compared to our lowly 23,000. We’ve evolved with bacteria for over a millennia and science is just beginning to investigate the important, symbiotic relationship between gut microflora and human health. Aside for being a crucial protective interface between the environment and our delicate mucosal lining, gut microflora perform important functions for our health like developing immune cells, digesting plant polysaccharides into short chain fatty acids and bioactivating essential vitamins for overall health. As we travel through the birth canal, we’re invaded by trillions of bacterial species and play host to niche colonizing pathogenic and non-pathogenic microorganisms throughout our lifetime. If you’re a germaphobe, it’d be prudent to know that bacteria, yeasts, fungi and viruses exist on our skin, mouth, hair, throat, stomach, intestines and colon, providing protection in most instances. This is why you hear educators discussing our viral load, bacterial load or fungal load and how eating organic, raw, whole foods, maintains healthy microbial populations, preventing disease. Each of us has a unique digestive microbiome that is negatively affected by somatic disturbances such as processed foods, antibiotics, tap-water, stress and inactivity. When an imbalance occurs, it’s known as a dysbiosis, which translates from Greek to, dys (bad) biosis (way of living). Scientist have found certain gut microflora like firmicutes spp play a role in obesity by harvesting energy from foods and increasing absorption of simple sugars while other microbial strains such as bacteroidetes and lactobacillus paracasei increased anorexigenic ( Greek an=without, orexis=appetite) gut hormones. Healthy gut microflora also elevate fasting-induced adipose factor (FIAF) a lipoprotein lipase (LPL) inhibitor. Remember LPL is involved in fatty acid uptake in fat cells, so FIAF blocks it ability to create plump, triglyceride rich belly fat. Healthy microflora levels also increases more anorexigenic gut hormones (PYY, choleocystokinin) that interact with ghrelin a hunger signaler. Consuming processed foods changes gut microflora levels predisposing individuals to increased energy storage and obesity. When you begin eating more organic, raw nuts, seeds, beans, legumes, fruits and vegetables, gut microflora levels balance out and produce healthy saccharolytic byproducts (fermentation). Ingestible polysaccharides are broken down by gut microflora into short chain fatty acids (SCFA) butyrate, acetate and propionate. Each of these SCFA exhibit distinct benefits, butyrate energizes colonic epithelial cells, propionate is taken up into the liver and acetate is utilized by skeletal muscle cells. Propionate, acetate and butyrate each increase anorexigenic gut hormones which control appetite by activating peptide YY which suppresses neuropeptide Y in the arcuate nucleus. Through the activation of G protein-coupled receptors (GPCR) 41 and 43 by SCFA’s acetate and propionate which induce the release of the anorexigenic gut hormone peptide yy (Pyy) slowing overall gut motility and speeding up intestinal transit time. This anorectic action of Pyy suppresses appetite and reduces calorie extraction from foods. (Note: GPCR, G protein- couple receptors our cell surface receptors that receive and communicate messages-informing a cell about life sustaining essential nutrients and or messages from other cells.) Also, GPCR41 mediates the microbial fermented SCFA’s upregulation of the fat hormone Leptin which travels to the brain and directly binds to neuropeptide Y in the arcuate nucleus to end hunger signals. Leptin plays a major role in food intake and energy balance. Studies have also shown that Leptin positively regulates the size and function of fat cells.
Our digestive systems host 85% friendly bacteria known as probiotics and 15% opportunistic pathogenic bacteria. Probiotics or pro-biotic meaning pro-life bacteria balance our digestive processes while controlling bad microorganisms which prevent a dysbiosis or imbalance in intestinal microflora. One important role probiotics perform to maintain microbial balance is ushering glucuronidation enzyme packages out of the body. Glucuronidation is the detoxifying process where fat soluble toxins and hormones such as harmful xeno-estrogens are solubilized into inert water soluble molecules and packaged onto glucuronic acids for removal. Opportunistic pathogenic bacteria can secrete an enzyme, beta-glucuronidase that uncouples this water soluble bond, so both the pro-carcinogenic estrogens and toxins recirculate back into the body. This is why supplementing with a good probiotic containing both lactobacilli and bifidobacteria strains prevents beta-glucuronidase from being secreted by harmful gut microflora. Keep in mind, we’ve coevolved with bacteria and other microorganisms and even though some are opportunistic pathogens such as H. Pylori, they play a fundamental role in our health. According to researchers working in NYU’s Blaser Lab Group, so called bad microflora like Helicobacter Pylori (H. Pylori) play a fundamental role in hunger signaling. After a bout of antibiotics, researches showed that endogenous ghrelin levels remained elevated after a meal. Ghrelin is a hormone that signals the brain to keep eating. In a commentary in the journal Nature, Dr. Blaser emphasized the critical importance of our gut microecology and pointed out that bacterial species such as H. Pylori have existed in the human digestive system for over 58,000 years. Across the country, Dr. David Relman, a professor of microbiology and immunology at Stanford University, recently stated: “It’s intriguing and entirely possible that in the future we will get a cocktail of strains and species of bacteria to repair the collateral damage that antibiotics and other practices have done to our inner ecology.” To further put things into perspective, farmers have known for years that antibiotics promote weight gain in livestock without changing caloric intake.