Butyrate - good or bad?SCFAs butyrate FODMAPs bacterial dysbiosis SIBO resistant starch colonic health intestinal gas methane constipation
Posted 01 May 2014 - 05:45 AM
This is one of the toughest questions for anyone with IBS. The low FODMAP diet, which reduces IBS symptoms by excluding gas-producing foods in only supposed to be temporary. High FODMAPs which form butyrate are generally healthy for the colon and should be gradually reintroduced. The re-introduction theory seems to assume that either there is no bacterial dysbiosis or if there was, the bacterial colonies have righted themselves.
Studies indicate that long-term diet management does make a difference to good bacteria repopulation although testing hasn’t indicated an actual time frame for this to occur. It’s doubtful to assume significant change will occur within a few months.
This makes things difficult for us. We want to reduce IBS symptoms but we also want to heal the colon. Could we cause more harm than good if we reintroduce FODMAPs too early? The other issue is that the low FODMAP diet is dull and restrictive, and we all crave variety in our diet. It’s hard maintaining a low FODMAP diet day after day, week after week.
If you do decide to gradually reintroduce FODMAPs it might just be a case of trial and error to see which FODMAPs are the most tolerable.
Basic facts (all derived from included links):
Butyrate is a short chain fatty acid which is a byproduct from fermentation of nondigestible carbohydrates such as resistant starch, pectin, cellulose, and unabsorbed sugars. Short Chain Fatty Acids (SCFAs) play an essential role in the health of the colonic epithelial cells and intestinal barrier function. Butyrate decreases colonic epithelial permeability.
Butyrate is an energy source for enterocytes, the cells that line the intestinal wall. Butyrate mediates the colonic inflammatory response and is thought to be a preventative against colon cancer. Butyrate can prevent the overgrowth of pathogens and promotes immune system T regulatory cells.
Butyrate has an important role on colonic mucosa, can stimulate mucous secretion, motility and sodium and water absorption and thereby prevents diarrhea.
Gut bacteria from fibre, FODMAPs and resistant starches produce gasses such as hydrogen, carbon dioxide and methane, which can be powerful IBS triggers.
Methane gas is implicated in IBS-constipation type due to mucosal stimulation causing segmental, non-propagating contractions.
(Propagating contractions involve the rapid propulsion of intraluminal contents from transverse colon to sigmoid colon. Most of the fluid in our colon has to be reabsorbed in prevent dehydration. Because of this most colonic contractions are non-peristaltic. These contractions move the contents back and forth but not forwards. High amplitude propagating contractions (HAPC) occur several times a day and are very strong contractions. They move contents from the first part of the large intestine to the rectum.)
Short chain FODMAPs are more rapidly fermented than long chain carbohydrates. Breath hydrogen is greatest for lactulose, less for inulin and least for resistant starch. Starches are generally excluded under the SIBO diet or for anyone who suspects bacterial dysbiosis but not all starches are problem foods and levels of intolerance differ according to the individual. Resistant starch passes through the short intestine relatively undigested and ferments in the colon. Opinion seems divided on how this affects SIBO.
It is possible that a proliferation of SCFAs and lactic acid could disrupt the intestinal mucosal barrier. Epithelial injury and permeability is related to rate of fermentation.
Bacteria in the Intestine, Helpful Residents or Enemies from Within?
Colonic butyrate- algesic or analgesic?
Bugs and Irritable Bowel Syndrome: The Good, the Bad and the Ugly
Personal view: food for thought – western lifestyle and susceptibility to Crohn's disease. The FODMAP hypothesis
Fecal butyrate levels vary widely among individuals but are usually increased by a diet high in resistant starch.
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Posted 01 May 2014 - 11:11 AM
Thanks for posting this. This is something I've been giving thought to myself. In the end, after gut healing has taken place, theoretically, I should be able to return to a more normal diet and not worry if I'm eating small amounts of fermentables. It's just not the reality right now.
Any fermented starch should contain butyrate. There's no need to let the fermentation happen inside your own body and cause gas and bloating during the process. The GAPS diet is based on the concept of eating many fermented foods. I personally prefer not to swallow the live bacteria of random ferments though, so if I ferment things I cook them before eating. There are exceptions I make to this rule, but I try to be fairly precise about what bacteria/yeast I deliberately swallow.
Ever been to the Museum of Medical Oddities in Philadelphia, PA? My picture is from there. That's the guy with the megacolon. I suppose he lived before surgery could help him. His actual colon is there too, thick as my leg.
Posted 01 May 2014 - 02:38 PM
I don't know if I would ask if butyrate is good or bad. The documents you cite show little evidence that butyrate is "bad" for humans, though they do show some adverse effects on rats. The question seems to be are indigestible substances good or bad. The trendy indigestible substance these days is the resistant starch in potatoes. But there are studies on the therapeutic uses of lactulose, fibers, and all kinds of prebiotics. Yet I, and many others with IBS. have always had an exacerbation of my symptoms when I have consumed these indigestible substances.
However, I make it a point to consume large quantities of grass-fed butter each day, specifically to get butyrate. I have not noticed any beneficial effects from it but I also have not noticed any adverse effects. And, as I just stated, when I consume substances that are purported to provide a substrate for SCFA-producing bacteria I do get adverse effects.
As the articles you cite point out, the microbes that consume these indigestible substances have many other metabolic byproducts besides butyrate. It appears to be highly likely that the adverse effects that these substances often cause are due to the non-butyrate byproducts. So, butyrate is probably good, or, at least, adiaphorous.
The effects of indigestible substances are still up in the air. Norm Robillard is at one extreme. He advocates (in his Fast Tract . . . series of books) minimizing fermentable (indigestible) substances. The advocates of potato starch are in the middle. They argue that some fermentable materials are beneficial. And the proponents of all kinds of fiber, roughage, and prebiotics are at the other extreme. Of course they don't argue that the gut should ferment as much as it can. But the consequence of their diet is that there will be a high amount of material being fermented in the gut.
My view is that the microbiome is an incredibly diverse and complex universe. None of us have any real alternative but to test on ourselves.
Posted 01 May 2014 - 05:34 PM
Thanks for the replies. I got caught with buying what I thought was fermented sauerkraut. It was just pickled in vinegar so you have to check the label carefully and buy from a trusted manufacturer. Substituting indigestible carbs with butter or fermented foods could be swapping one troublesome food for another. A lot of us have problems digesting fats and one effect is lipid-induced intestinal gas retention. Fermented food can be high in histamines which causes IBS symptoms as well. I know a lot of us rely on cooking methods to reduce gas but I'm wondering if doing this actually reduces the high FODMAPs to simple sugars. I was thinking of emailing the Monash University and asking them if they're going to do a study on cooking methods and whether these degrade FODMAPs to such an extent that you lose the benefit of eating them in the first place. It gets to a stage where all foods seem to cause problems but this is probably more due to our bacterial dysbiosis than the food itself. Healthy people get bloating from problem foods as well, especially bread, but the symptoms aren't as severe for them. I think a healthy diet can change bacterial enterotype but I don't know how long this takes. The idea is to stop eating refined sugars (sugar, white flour etc) to cause die-off of the bacteria that feed on these while eating more high FODMAPs, to repopulate the good bacteria. There's a lot of theory but little proof. It's very complex because if you still have the bad bacteria this can potentially cause leaky gut problems as outlined in Sue Shepherd's link re Crohn's disease. I just go by instinct and I think that's what we all have to do. If your symptoms gradually improve then you must be on the right track. The only way I get through the day with little gas is by eating toasted or mashed foods but then you wonder what good these foods are if they don't produce SCFAs.
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