I have been excited about butyrate because rat studies showed that it increased the motility of the colon (please let’s not dwell much too long on the fact I’m reduced to rat status and writing about constipation). I am going to summarize and explain an abstract to a study, from which the following quote is taken:
“Little is known about the environmental and nutritional regulation of the enteric nervous system (ENS), which controls gastrointestinal motility. Short-chain fatty acids (SCFAs) such as butyrate regulate colonic mucosa homeostasis and can modulate neuronal excitability. We investigated their effects on the ENS and colonic motility.”
~ from Gastroenterology, 2010, “Short-chain fatty acids regulate the enteric neurons and control gastrointestinal motility in rats.” Emphasis was mine.
Aside: Please note that I am probably a fool and excited about nothing, but it is a path worth exploring for my slow transit constipation. Also note, I do my best to simplify studies and concepts, some of which are difficult for my basic molecular biology background. My husband, being an exceptionally logical and fact oriented doctor, hates it when I do this. Big time scowls. He is right, sometimes the explanations become kind of inaccurate. So I will do the best I can. If you have any questions or note any errors, I would like to know. Gaps in my understanding will be bridged this way. And one last note, don’t use my blog stuff to cause any harm to yourself. Please. See your doctor.
What did these researchers do?
- Fed rats a resistant starch diet. (I will write a resistant starch post soon. Soon is always relative.)
- Inserted short chain fatty acids (i.e. butyrate) into rats’ cecums (a part of their colons). (I only have an abstract so we are left to our imaginations for this lovely process.)
- Applied butyrate to some “free-standing” cultures of enteric nervous system cells in a “test tube.”
- In the “test tube” cells, they examined how the cell “looked”–its “phenotype.” What kind of receptors did the nervous system cells have on their outer membranes? What kind of proteins are expressed? Knowing this kind of information helps us to know what the cell is capable of responding to and what substances the cell makes. Special antibodies that will seek out these known proteins and receptors on the cells are used. Researchers also used polymerase chain reaction (PCR), a way to amplify and increase certain material. Specifically, these researchers looked for antibodies to Hu, choline acetyltransferase (ChAT), and nitric oxide synthase (NOS). If you refer back to “Changes in Severe, Chronic Constipation,” you will see a couple of these discussed: Less neurons immunoreactive for ChAT and more neurons immunoreactive for NOS. They also proceeded to analyze signaling pathways using various tests.
- Observed the motility of the colon both in the rat and outside the rat.
What were the results?
- Resistant starch diet (which increases butyrate) and butyrate (but NOT acetate and propionate, other short chain fatty acids made from resistant starch by the colon’s bacteria) both:
A. Increased the ChAT neurons, these are the ones partly responsible for increasing peristalsis. Neurons with ChAT should make more acetylcholine, the neurotransmitter that encourages the bowel to move forward and empty.
B. Did not alter the NOS neurons’ proportion and number. NOS would bring about nitric oxide, which slows down the bowel’s movements. It makes the bowel relax rather than move.
Bowel neurons have a transporter called monocarboxylate transporter 2 (MCT2), which helps bring butyrate into the colon cell after the bacteria graciously make it. Well, the researchers were able to “stop” these transporters so butyrate wouldn’t move into the cell so much. By stopping the MCT2 transporters, the increase in ChAT neurons–and therefore neurons that would increase colon motility–was halted.
Butyrate increased histone H3 acetylation in enteric neurons. When DNA is acetylated, it allows the DNA to be transcribed. So butyrate alters the actual genetic expression of cells.
Resistant starch diet increased colonic transit.
Ex vivo it was noted that butyrate increased the circular muscles contraction when exposed to acetylcholine.
“Butyrate or histone deacetylase inhibitors might be used, along with nutritional approaches, to treat various gastrointestinal motility disorders associated with inhibition of colonic transit.” And that’s as far as I’ve seen it up to this post. I’ll keep looking.
I’m not trying to live forever. I don’t have cancer yet. I’m eons away from a stroke. But my gut has a mind of its own. In addition to more information on butyrate (and resistant starch), I need to explore the outcomes of slow transit constipation in 80 year-old women. Do they have a study on that? Right now, things are tolerable with all the changes I’ve made the last 18 months or so of my life, but what happens later? Or when the magnesium stops working again? Anyhow, here are my closing thoughts:
- Butyrate is made in the gut and absorbed by the gut. The gut has been my constant, lifelong problem.
- Butyrate may affect the immune system and decrease inflammation. We have studies supporting food intolerances causing severe, chronic constipation and these studies document subtle inflammatory changes in the mucosa.
- Butyrate may affect the nervous system through modulation of gene expression. We know the enteric nervous system is messed up in slow transit constipation.
- Butyrate may stimulate the contractile activity of the colon and accelerate GI transit. We know slow transit constipation has a reduction in high amplitude propagating contractions and a disruption of the coordinated peristaltic activity.
- Butyrate is increased by eating resistant starch, a type of “fiber.” (This is a bit confusing, but I will clarify later. Resistant starch would be high in diets rich in lentils, beans, tubers, etc. Please see Butyrate Series, Part 6 for a better, more thorough explanation) Fiber has long been recommended for constipation. Perhaps it’s not the fiber. It could be the fiber. Or it could be a rich bacterial population capable of making more butyrate for an individual.
- Butyrate has been shown to possibly decrease colon cancer. Colon cancer is higher in patients with chronic constipation (Chronic Constipation Linked To Increased Risk of Colorectal Cancer–summary article from Science Daily).
And finally, I’ll leave you with this quote:
“If the promising results by Soret et al [the paper whose abstract I summarized and explained above] can be confirmed and expanded by controlled therapeutic trials, then butyrate-generating foods might become an effective and simple option to prevent or treat functional gut disorders via modulation of enteric neuroplasticity.” (2–a very good little commentary to read!)
1. Soret R, Chevalier J, De Coppet P, Poupeau G, Derkinderen P, Segain JP, Neunlist M. Short-chain fatty acids regulate the enteric neurons and control gastrointestinal motility in rats. Gastroenterology. 2010 May;138(5):1772-82. Sadly, abstract only: http://www.ncbi.nlm.nih.gov/pubmed/20152836
2. de Giorio R, Blandizzi C. Targeting Enteric Neuroplasticity: Diet and Bugs as New Key Factors. Gastroenterology. 2010 May; 138(5):1663-1666.
Also, if you will please see “Why Does My Gut Defy Gravity: Changes in Severe, Chronic Constipation” and “But What Causes All of Those Changes Found in Chronic, Severe Constipation?” and “Cow’s Milk and Refractory Constipation” then you can find further information plus sources for that information and information mentioned above.
I also have run a whole series on butyrate. I need to come back and link eventually; the WordPress blogging platform used to have a feature to do that but not now. If you look under GI Tracts Defies Gravity page, there are links there to the series pieces.
- Butyrate Is Important For YOU (thehomeschoolingdoctor.com)
- Why Does My GI Tract Defy Gravity: Changes in Severe, Chronic Constipation (thehomeschoolingdoctor.com)
- A Kid’s Conversation on Butyrate (Fiber – To Way Oversimplify) (thehomeschoolingdoctor.com)
- Slow Transit Constipation: A True Enteric Neuropathy (thehomeschoolingdoctor.com)
- But What Causes All of Those Changes Found in Chronic, Severe Constipation? (thehomeschoolingdoctor.com)