Monthly Archives: September 2014

Brain/Gut/Symbiont function seen as Rock-Paper-Scissors. Or, why you crave french fries and can’t lose weight!

Rock-Paper-Scissors is an ancient Chinese game, often used in modern society instead of flipping a coin. The concept is that each player, on que, puts his hand out flat (paper) or in a Vulcan-like “V” (scissors), or a fist (rock). Each beats the next: scissors cut paper, paper covers rock, rock crushes scissors. It occurred to me that this is quite similar to how symbiont bacteria, the brain, and the gut interact! I’ll explain the short version, then explain more about it. The symbiont bacteria influence the brain, the brain controls the gut (intestines) and the intestines provide a habitat/home for the symbionts. Imbalances in any of these three can therefore affect the next item in the functional triad: Imbalanced symbionts (dysbiosis) can alter brain neurotransmitters, mood, pain perception, cognition, sense of smell, appetite for specific foods and behaviors. Alterations of this type in the brain result in, amongst other things, cravings for specific foods that would benefit the dominant genera of gut symbionts combined with discomfort/lack of satisfaction if those cravings are not met. Here’s a very common example: one pattern of gut bacteria imbalance results in what researchers have termed “obesogens”, dominant populations of bacteria that cause obesity. How do they do that? In part, by altering appetite, olfaction (sense of smell), and frontal lobe processing to create food cravings and increased appetite, specifically for foods that benefit the bacteria-in this case greasy/sweet and fattening foods. Along with this dietary predilection there are behavioral changes that result in lower energy levels, less ambition, and a preference for a sedentary lifestyle that does not burn calories. These behavioral changes have been evaluated in laboratory animals by taking a sterile (no bacteria) animal of normal weight and transferring the gut bacteria from an obese animal to it. The result is a behavioral and appetite/food preference change similar to that which the obese animal had! In other words, the behavior goes with the bacteria. So, what do you do if you want more energy, want to lose weight and get more done? try to work on improving your gut bacteria! Pre and probiotics as well as exercise and dietary changes provide some ways to accomplish this.

Here’s another example of this triad at work: a stressful lifestyle affects the brain’s control of the gut, by altering autonomic function and causing sympathetic (fight-or-flight) dominance. This suppresses the gut digestive process and causes more putrefaction, altering the balance of symbiont populations. Damage to the mucous lining of the intestines and sloughing off of microvilli that normally improve nutrient absorption and house gut bacteria reduce beneficial symbiont populations. What’s the result? As above, weight gain and a cascade of health problems.

The changes to the symbiont bacteria can alter brain function sufficiently to cause depression, anxiety, irritable bowel syndrome, autism, ASD, and altered brain function, personality and pain perception. These are deeply fundamental changes to “who we are” and are representative of the level of influence that the gut symbionts have on our function.

The “rock paper scissors” explanation should also illustrate why researching specific cause-effect/double blind mechanisms are so challenging in this system, as unless the third variable is controlled for (and it often cannot be) the results may be more inconsistent that they would be in a simpler system.

This functional trifecta is one of the reasons why in my clinic, if I recommend an exercise and a dietary change and the patient immediately becomes resistant and “whiney” about making the changes, I record the resistance as a symptom and try to show the patient how their feelings are in fact potential confirmation of this functional system at work!

References:

Modulation of Intestinal Microbiota by the Probiotic VSL#3 Resets Brain Gene Expression and Ameliorates the Age-Related Deficit in LTP.

Distrutti E, O’Reilly JA, McDonald C, Cipriani S, Renga B, Lynch MA, Fiorucci S.

PLoS One. 2014 Sep 9;9(9):e106503. doi: 10.1371/journal.pone.0106503. eCollection 2014.

PMID:
25202975
[PubMed – in process]

Free Article

2.

Gut microbiota, the pharmabiotics they produce and host health.

Patterson E, Cryan JF, Fitzgerald GF, Ross RP, Dinan TG, Stanton C.

Proc Nutr Soc. 2014 Sep 8:1-13. [Epub ahead of print]

PMID:
25196939
[PubMed – as supplied by publisher]
3.

Probiotics normalize the gut-brain-microbiota axis in immunodeficient mice.

Smith CJ, Emge JR, Berzins K, Lung L, Khamishon R, Shah P, Rodrigues DM, Sousa AJ, Reardon C, Sherman PM, Barrett KE, Gareau MG.

Am J Physiol Gastrointest Liver Physiol. 2014 Sep 4. pii: ajpgi.00238.2014. [Epub ahead of print]

PMID:
25190473
[PubMed – as supplied by publisher]
4.

Obese-type Gut Microbiota Induce Neurobehavioral Changes in the Absence of Obesity.

Bruce-Keller AJ, Salbaum JM, Luo M, Blanchard E 4th, Taylor CM, Welsh DA, Berthoud HR.

Biol Psychiatry. 2014 Jul 18. pii: S0006-3223(14)00520-4. doi: 10.1016/j.biopsych.2014.07.012. [Epub ahead of print]

PMID:
25173628
[PubMed – as supplied by publisher]
5.

Enteric Bacterial Metabolites Propionic and Butyric Acid Modulate Gene Expression, Including CREB-Dependent Catecholaminergic Neurotransmission, in PC12 Cells – Possible Relevance to Autism Spectrum Disorders.

Nankova BB, Agarwal R, MacFabe DF, La Gamma EF.

PLoS One. 2014 Aug 29;9(8):e103740. doi: 10.1371/journal.pone.0103740. eCollection 2014.

PMID:
25170769
[PubMed – in process]

Free PMC Article

6.

Altered brain-gut axis in autism: Comorbidity or causative mechanisms?

Mayer EA, Padua D, Tillisch K.

Bioessays. 2014 Oct;36(10):933-9. doi: 10.1002/bies.201400075. Epub 2014 Aug 22.

PMID:
25145752
[PubMed – in process]
7.

Is eating behavior manipulated by the gastrointestinal microbiota? Evolutionary pressures and potential mechanisms.

Alcock J, Maley CC, Aktipis CA.

Bioessays. 2014 Oct;36(10):940-9. doi: 10.1002/bies.201400071. Epub 2014 Aug 8.

PMID:
25103109
[PubMed – in process]
8.

Microbiota-host interactions in irritable bowel syndrome: epithelial barrier, immune regulation and brain-gut interactions.

Hyland NP, Quigley EM, Brint E.

World J Gastroenterol. 2014 Jul 21;20(27):8859-66. doi: 10.3748/wjg.v20.i27.8859.

PMID:
25083059
[PubMed – in process]

Free PMC Article

9.

Serotonin, tryptophan metabolism and the brain-gut-microbiome axis.

O’Mahony SM, Clarke G, Borre YE, Dinan TG, Cryan JF.

Behav Brain Res. 2014 Jul 29. pii: S0166-4328(14)00476-8. doi: 10.1016/j.bbr.2014.07.027. [Epub ahead of print]

PMID:
25078296
[PubMed – as supplied by publisher]
10.

Digesting the emerging role for the gut microbiome in central nervous system demyelination.

Joscelyn J, Kasper LH.

Mult Scler. 2014 Jul 28. pii: 1352458514541579. [Epub ahead of print] Review.

PMID:
25070675
[PubMed – as supplied by publisher]
11.

The impact of microbiota on brain and behavior: mechanisms & therapeutic potential.

Borre YE, Moloney RD, Clarke G, Dinan TG, Cryan JF.

Adv Exp Med Biol. 2014;817:373-403. doi: 10.1007/978-1-4939-0897-4_17.

PMID:
24997043
[PubMed – in process]
12.

Microbiota-gut-brain axis and cognitive function.

Gareau MG.

Adv Exp Med Biol. 2014;817:357-71. doi: 10.1007/978-1-4939-0897-4_16.

PMID:
24997042
[PubMed – in process]

One big step closer to publication!

IMG1712
Look what came in the mail yesterday! It is a physical, hold-it-in-your-hands printed copy of my book. This is a proof copy, so it is at the moment the only one of its kind-but it means that The Symbiont Factor will be published very soon! It is remarkable to hold and read it, after a year of only seeing it in my mind or on my computer. Thanks to all of you that have been following along and offering support!