Over 2,500 years ago the so-called founder of modern medicine, Hippocrates, said that all disease begins in the gut. And evidence shows us that he was right.
While an ever-expanding body of research indicates just how chronically sick our guts can make us, this doesn’t mean that the gut necessarily holds all of the answers to everything that we do not understand.
A kind of black box to which we can open Pandora’s box…
Or does it?
The Gut Microbiome as Pathogen Protector
The gastrointestinal tract (GIT), in other words, the gut, is the largest interface between the human organism and the outer environment, deeply involved in maintaining our health.
A giant panoply of microorganisms whose composition directly impacts our epithelial barrier and gut immune system functions is hosted in the lumen (membrane) of the gut and in the upper mucus layer.
Our health status is influenced by these microorganisms.
For example, probiotics (good bacteria which confirm health benefits to us), can increase macrophage and natural killer cell activity, modulate immunoglobulin or cytokine secretions, as well as indirectly enhance the gut epithelial barrier, alter mucus secretion, and competitively exclude pathogenic bacteria from taking hold. (1)
Correlation, So What About Causation?
Every scientist knows that correlation does not equal causation, yet somehow that can be a difficult concept to remember to stomach at all.
It’s all correlation until somebody gets hurt, right? Cause-effect relationships between pathology and the microbiome are not well established, ad infinitum. It’s a story on repeat when it comes to health and wellness.
And then, bam! We have ourselves a mechanism of action, where the real stuff happens. Where we can dig in. Where there might be a patentable drug mechanism of action lurking in the shadows, and where there may be the ability to obtain research grant funding and warranting further research to confirm the as-of-yet unconfirmed.
For the last two decades or so we’ve heard endlessly about the microbiome and the gut-brain axis.
But your gut is not a black box. Just because it can make us extremely sick doesn’t mean that it’s necessarily responsible for all of the things that we do not understand right now.
Fact #1: 70% Of Your Immune System Is Housed In Your Gut
Depending on who you talk to, anywhere from 60 to 80 percent of our immune cells reside in our gut.
Not only immune cells, but approximately 100 trillion gut bacteria also reside there, comprising our intestinal microflora which can take care of pathogens as well as become pathogenic. (2)
When the Pathogen Monster Can Become Pathogenic
Basically, our immune system is inside our body, and bacteria live outside our body—or are they inside our body, and our body is outside?
These two layers have a life-long conversation, during which millions of antibodies are generated and secreted by cells lining the gut. Our body’s homeostasis and our immunostasis go hand-in-hand.
Hence, if your gut is messed up, you just might get sick a lot more often, and you also just might be liable to get a chronic disease.
For example, the intestinal microbiota serves as a protective mediator during pneumococcal pneumonia, enhancing primary alveolar macrophage function. (3) Patients with diverticular disease have depleted anti-inflammatory microbiota associated with mucosal macrophage infiltration. (4)
Multiple pathologies are associated with dysbiosis or unbalanced gut microflora, as host susceptibility to infections, autoimmune disease, chronic disease, and even cancer, becomes heightened. (5)
Dysbiosis, most prominent in the digestive tract, is the condition of having microbial imbalances on or within the human organism. It can also occur on any surface or mucus membrane, such as skin, sinus, nose, lung, ear, nail, eye, or vagina.
Dysbiosis, of which dysbacteriosis is a subtype, is not so much about the germ as it is about the effect that the germ (or microbe) can have on a susceptible host. In other words, dysbiosis is about a relationship between host and microbe. (6)
Studies abound showing links between Parkinson’s disease and pathogenic bacteria, as well as the myriad associations between IBS and SIBO, and between SIBO and a host of other chronic diseases. (7, 8)
Fact #2: Probiotics Can Make Some People Sick
Interestingly, most so-called dairy free probiotics contain dairy in them, yet dairy is the most common food sensitivity in the world. (9)
Labels usually read “dairy free,” but the fact is often that a dairy culture medium has merely been washed off and regulations do not require the labeling of such.
The reason is that most modern starter cultures originate from lactic acid bacteria that originally constituted milk microflora. The lactic acid live active culture is not considered to be dairy related because after the medium has been washed off it does not contain any milk or milk protein. (10)
Hence, many vegan or dairy-free labeled commercial probiotics may contain some tiny amount of dairy derivatives and make a person who is dairy sensitive or intolerant less healthy and produce symptoms, such as gas, bloating, and congestion, consistent with their epigenetics and constitution.
Probiotics obviously represent a powerful tool in order to reestablish homeostasis and promote gut health, but only if they are 100% dairy free for those who are sensitive to dairy derivatives.
This can occur not only via the innate and adaptive immunity, but through other mechanisms: intestinal epithelium permeability regulation, mucus secretion, and competitive antimicrobial compound secretion.
For example, three probiotics that have been shown to be 100% dairy free are Ayush 100B, MegaSporeBiotic, and Therbiotic.
Fact #3: 90% Of Your Serotonin Is Made In Your Gut
90% of our serotonin is made in the gut and can cross the blood-brain barrier. (11) Serotonin is known as the happiness neurotransmitter, and it’s also required in learning and attention.
Hence, it doesn’t take a rocket scientist to deduce that if your gut is messed up, you’ll be more likely to experience anxiety and depression, as well as symptoms of attention deficit disorder.
Fact #4: Psychobiome Aside, There May Be A Microbiome in Our Brain
New research has been coming out that we may even have good (or bad?) bacteria in our brain. (12) We have been finding more and more information about the psychobiome lately, that is, the gut bacteria that may impact how we think and feel. But what about the brain microbiome, now indicated in preliminary research findings? (13, 14)
Fact #5: The Gut Makes A Lot of Critically Important Nutrients
Not only is our microflora responsible for generating Vitamin K, essential to blood coagulation and bone metabolism, but it also plays a role in the production of the eight water soluble B vitamins, namely biotin, cobalamin, folate, niacin, pantothenate, pyridoxine, riboflavin, and thiamin, required for methylation and detoxification pathways. (15)
Therefore, it stands to reason that if our gut is messed up, we may quickly become deficient in key minerals and nutrients to generally get things done in our bodies, such as metabolism, methylation, and detoxification.
Fact #6: You Can Change Your Microbiome Composition In Just One Day
It’s a fact that it only takes one day to completely change our microbiome. This can be done by what you eat, or by a dose of antibiotics. (16) Hence, be mindful of what you’re putting into your gut!
What’s Gut Got to Do, Got to Do with It?
The moral of the story is that you may not need a black box warning to discover that what you put in you will likely get out, in the long run, when it comes to gut health and living a life free of chronic disease.
However, the gut is not a black box because we know that it is where much of chronic disease first begins, to paraphrase Hippocrates.
Nurture your microbiome, nurture your psychobiome, support homeostasis and immunostasis, and keep dysbacteriosis at bay.
Study the science of nutrition’s black box warnings and know that even though the gut may appear to be a black box at best and a Pandora’s box at worst, it’s neither. By understanding more, you can begin to nurture your microbiome and your psychobiome, support homeostasis and immunostasis, and keep dysbacteriosis at bay.
- La Fata G, Weber P, Mohajeri MH. Probiotics and the Gut Immune System: Indirect Regulation. Probiotics Antimicrob Proteins. 2018 Mar;10(1):11-21. doi: 10.1007/s12602-017-9322-6. PMID: 28861741; PMCID: PMC5801397.
- Ahluwalia B, Magnusson MK, Öhman L. Mucosal immune system of the gastrointestinal tract: maintaining balance between the good and the bad. Scand J Gastroenterol. 2017 Nov;52(11):1185-1193. doi: 10.1080/00365521.2017.1349173. Epub 2017 Jul 12. PMID: 28697651.
- Schuijt TJ, Lankelma JM, Scicluna BP, de Sousa e Melo F, Roelofs JJ, de Boer JD, Hoogendijk AJ, de Beer R, de Vos A, Belzer C, de Vos WM, van der Poll T, Wiersinga WJ. The gut microbiota plays a protective role in the host defence against pneumococcal pneumonia. Gut. 2016 Apr;65(4):575-83. doi: 10.1136/gutjnl-2015-309728. Epub 2015 Oct 28. PMID: 26511795; PMCID: PMC4819612.
- Barbara G, Scaioli E, Barbaro MR, Biagi E, Laghi L, Cremon C, Marasco G, Colecchia A, Picone G, Salfi N, Capozzi F, Brigidi P, Festi D. Gut microbiota, metabolome and immune signatures in patients with uncomplicated diverticular disease. Gut. 2017 Jul;66(7):1252-1261. doi: 10.1136/gutjnl-2016-312377. Epub 2016 Sep 12. PMID: 27618836.
- Lazar V, Ditu LM, Pircalabioru GG, Gheorghe I, Curutiu C, Holban AM, Picu A, Petcu L, Chifiriuc MC. Aspects of Gut Microbiota and Immune System Interactions in Infectious Diseases, Immunopathology, and Cancer. Front Immunol. 2018 Aug 15;9:1830. doi: 10.3389/fimmu.2018.01830. PMID: 30158926; PMCID: PMC6104162.
- Martinez KB, Leone V, Chang EB. Western diets, gut dysbiosis, and metabolic diseases: Are they linked? Gut Microbes. 2017 Mar 4;8(2):130-142. doi: 10.1080/19490976.2016.1270811. Epub 2017 Jan 6. PMID: 28059614; PMCID: PMC5390820.
- Sun MF, Shen YQ. Dysbiosis of gut microbiota and microbial metabolites in Parkinson’s Disease. Ageing Res Rev. 2018 Aug;45:53-61. doi: 10.1016/j.arr.2018.04.004. Epub 2018 Apr 26. PMID: 29705121.
- Borghini R, Donato G, Alvaro D, Picarelli A. New insights in IBS-like disorders: Pandora’s box has been opened; a review. Gastroenterol Hepatol Bed Bench. 2017 Spring;10(2):79-89. PMID: 28702130; PMCID: PMC5495893.
- Sarao LK, Arora M. Probiotics, prebiotics, and microencapsulation: A review. Crit Rev Food Sci Nutr. 2017 Jan 22;57(2):344-371. doi: 10.1080/10408398.2014.887055. PMID: 25848935.
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- Yano JM, Yu K, Donaldson GP, Shastri GG, Ann P, Ma L, Nagler CR, Ismagilov RF, Mazmanian SK, Hsiao EY. Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis. Cell. 2015 Apr 9;161(2):264-76. doi: 10.1016/j.cell.2015.02.047. Erratum in: Cell. 2015 Sep 24;163:258. PMID: 25860609; PMCID: PMC4393509.
- Matarazzo I, Toniato E, Robuffo I. Psychobiome Feeding Mind: Polyphenolics in Depression and Anxiety. Curr Top Med Chem. 2018;18(24):2108-2115. doi: 10.2174/1568026619666181210151348. PMID: 30526463.
- Says:, Jami Carpenter, Zhao says: Mari Luque Says: Ramesh Chaudhary says: and Name *. “Bacteria May Live Naturally inside the Human Brain,” November 27, 2018. http://sitn.hms.harvard.edu/flash/2018/bacteria-may-live-naturally-inside-human-brain/.
- Pennisi E. Meet the psychobiome. Science. 2020 May 8;368(6491):570-573. doi: 10.1126/science.368.6491.570. PMID: 32381701.
- Ramakrishna BS. Role of the gut microbiota in human nutrition and metabolism. J Gastroenterol Hepatol. 2013 Dec;28 Suppl 4:9-17. doi: 10.1111/jgh.12294. PMID: 24251697.
- Le Bastard Q, Al-Ghalith GA, Grégoire M, Chapelet G, Javaudin F, Dailly E, Batard E, Knights D, Montassier E. Systematic review: human gut dysbiosis induced by non-antibiotic prescription medications. Aliment Pharmacol Ther. 2018 Feb;47(3):332-345. doi: 10.1111/apt.14451. Epub 2017 Dec 5. PMID: 29205415.