Tuesday, November 06, 2007

Selling fiber and bacteria

I watch the Simpsons. I consider it essential viewing for the maintenance of sanity. Apparently an awful lot of people with either IBS or "normal" constipation do too, judging by the marketing wizards' placement of advertisements for probiotics and/or soluble fiber in the central ad slot. Drives me up the wall. So how effective are these interventions in improving bowel function?

Well, probiotics appear to be very strain related but can have benefits in some situations. Dr Hunter is a gastroeneterologist at Addenbrooks in Cambridge. Taking a combination of bifidobacteria and lactobacillus that looks remarkably like yogurt minimises anaerobic overgrowth when you are on an antibiotic for helicobacter. Fair enough. I ferment my cream with these bugs.

But the role of probiotics in IBS "has not been clearly defined". Probably depends on who funded the study. Certainly lactobacillus plantarum 299v is not too hot.

Lactobacillus casei strain Shirota is pretty interesting according to the company which sells it. Lovely graphics on the homepage BTW. How much did the web site cost? I guess nothing compared to their TV advertising budget.

But are they needed anyway? Two interventions which do work are compared, by Dr Hunter again, here:

Metronidazole (an antibiotic aimed at anaerobic lower bowel bacteria) is pretty good, reducing peak gas production from 671ml/min to 422ml/min. Obviously no one wants to take metronidazole long term in view of its serious interaction with alcohol and its occasional neurological toxicity. But it makes a fairly convincing case that the problem is a bacterial problem. What do bacteria eat that humans cannot digest? Fiber.

So the other intervention is a no-fiber diet. Peak gas production dropped from 564ml/min to 205ml/min. This looks to be very effective and very interesting.

Both improved symptoms. As fiber is of no use to humans and it appears to feed the bacteria that cause IBS, including good old klebsiella, you have to wonder where the medical fascination with fiber comes from...

We all know where fiber ends up, why suffer the gut problems it causes as it gets there?



Anonymous said...

Hi Peter...have you heard of Lactobacillus sporogenes...Thorne Research sells it and is use by veterinarians.

Peter said...

Hi Hela,

No, I don't know exactly which bacteria there are in the probiotic stocked by the practice I work at, but it's not this one. At the last medical meeting I went to (sponsored by Yakult, no surprise there) several speakers produced quite hard data which suggested that the strain or combination of strains is crucial to efficacy. That's partly why I use yogurt cultures for myself. Yogurt has stood the test of time quite well....


Anonymous said...

Do you know what the animals ate on the no-fiber diet? I doubt they got just meat, eggs, and dairy. Why did they produce any gas? They probably used sucrose and casein, maybe even flour and cornstarch. They may have had small amounts of fiber in their diets. Ex: zero-carb diet typically has traces of carbs, unless you eat only muscle meats and pure fats and oils. The no-fiber diet was named a "polymeric diet." Have you read the study to know what that means?

Peter said...

Hi Bruce,

No idea what the fiber free food was, only have the abstract. But they were humans doing the eating. Even if people are as in bred as they used to be in the Fens before the invention of the bicycle, they're still human!


Anonymous said...

Well, humans are animals. I skimmed the abstract and forgot it was done with humans, though. They could say that sugar was a no-fiber diet, eh? The "polymeric diet" brings to mind glucose polymers, AKA maltodextrin. Those may have caused fermentation, even in the absence of fiber.

gunther gatherer said...

If fiber feeds the gut bacteria, does that imply that eating glucose or sucrose without fiber would still starve them? Or do they eat that too?

My experience with eating high fat (80% of calories) was that gas went from frequent to nil in one day.

Several months on, I did an experiment and ate a chocolate bar (no fiber) and still had no gas. Peter, what is your rationale for eating potatoes (quite neolithic) as your main vegetable? Is there an advantage with regards to fiber or affect on but bacteria?

I did another experiment with eating just a baked potato with butter. No gas. Before I began all this, I was a windstorm after eating a roll, grilled vegetables, and lots of other "healthy" things. Please explain!


Marnee said...

Gunther, if you have been eating a very low fiber/low carb diet for some time then your level of gut bacteria might be lower and hence one potato or some chocolate may not be enough to produce noticeable gas.