Saturday, July 31, 2010

Irritable Bowel

Let's start with a bit of melancholy. I do so love this piece (right click to open in new tab) by Ralph Vaughan Williams. My 10th grade band director, who died in his early sixties of a heart attack, loved RVW too. There's plenty of tragedy in an ordinary life to go around, even now.

Last week when researching the lithium post I pulled another article from the Journal of Lipid Research that looked interesting. Its title: "Marked elevations in pro-inflammatory polyunsaturated fatty acid metabolites in females with irritable bowel syndrome." This article was produced by an Irish group, including a psychiatrist! Amazing what you find in the Journal of Lipid Research.

I see a lot of patients with IBS - basically, uncomfortable flatulence, bloating, constipation, and diarrhea, but no particular cause found. It is highly associated with depression and anxiety, thus my common involvement. And the researchers call IBS a "disorder of the brain-gut axis." But you may not be surprised that low-grade inflammation is suspected to be a predisposing factor, as evidenced by the presence of mast cell mediators (regulators of the cellular immune system) and lymphocytes in the colo-rectal mucosa, and elevations of pro-inflammatory cytokines in the serum of people with IBS.

(Yes. Inflammation. Imagine that.)

The study involved some comparison between people with IBS and normal controls. The IBS sufferers were selected from the gastroenterology clinic. The controls were found off the street, or however. Study participants filled out a few questionnaires and then had some blood taken (and centrifuged) for analysis. Some basic confounders were accounted for (such as smoking).

The findings: 41% of the subjects with IBS (17 out of 41 people) met the criteria for major depressive disorder. No one in the control group of 26 were depressed. The IBS group had a mix of constipation dominant vs. diarrhea dominant vs alternating symptoms.

And the fatty acids? IBS sufferers had lower plasma omega 6 and higher plasma omega 3 than the controls (WHA??? I know, sometimes science surprises - though this trend was not statistically significant), but the levels of arachidonic acid (created from omega 6 fatty acids, and the precursor for a ton of inflammatory cytokines) were significantly elevated compared to controls (p=0.029). The inflammatory cytokines themselves (prostaglandins and leukotrienes, if you must know) were also significantly elevated. There was no correlation between the severity of the symptoms and the elevations of the cytokines. Arachidonic acid does seem to play a role in intestinal permeability, so the researchers did not find its elevation surprising. They made note that diet might not be the only factor predisposing people to an inflammatory state.

It might not all be dietary! It might have to do with other stressful factors in life, and such. Those psychotherapy skills might be useful after all.

3 comments:

  1. Very interesting piece. You may find these studies on fructose malabsorption interesting. They link fructose malabsorption with IBS. They also note the higher incidence of depression/anxiety amongst fructose malabsorbers and IBS sufferers. The interesting finding is that fructose malabsorption is associated with reduced zinc, tryptophan and folate uptake from the gut.
    From an evolutionary perspective this is very interesting i.e. that our current high intake of free fructose, and wheat (a source of fructans) is contributing to such high instances of IBS and possibly psych illnesses.
    Another factor not addressed Id love to find more research on would be the small intestinal bacterial overload seen in fructose malabsorbers and any relationship that may have to bacterial endotoxin in the blood stream which is associated with systemic inflammation and the metabolic syndrome.
    anyway just thought you may be interested :-)
    Jad
    http://www.ncbi.nlm.nih.gov/pubmed/10961700
    Carbohydrate malabsorption syndromes and early signs of mental depression in females

    http://sacfs.asn.au/download/SueShepherd_sarticle.pdf
    Fructose Malabsorption and Symptoms of
    Irritable Bowel Syndrome: Guidelines for
    Effective Dietary Management

    http://en.wikipedia.org/wiki/Fructose_malabsorption
    wiki summary.

    http://www.clinchem.org/cgi/content/full/47/4/745
    Decreased Serum Zinc in Fructose Malabsorbers

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  2. Thanks, Jad. Amazing how the same things keep coming up over and over once you look closely at them. I'm going to have to learn more about fructose malabsorption.

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  3. Hi,

    How much of IBS could be related to gluten intolerance?

    I've come to this after my wife has gone gluten free for a year. She was previously diagnosed with IBS and doctors were saying that it was linked to or caused by depression brought on by marrying me. She didn't buy it because she didn't consider herself depressed. After numerous suggestions by her sister she went gluten free and after a couple of weeks sans gluten her energy levels are up, she doesn't need a nap after work every day, she has more energy to do things around the house. We decided all the IBS after the marriage was possibly due to all the Italian, pasta heavy, dinners I was cooking 3 to 5 times a week. The post marriage diet was also significantly different from her more Atkins diet that she was on before the wedding, which of course had almost no wheat what-so-ever.

    Any thoughts?

    P.S. Next month shes going into the doctor for a formal evaluation of her gluten intolerance which includes a prescribed 2 weeks of eating gluten before hand to see if there is any damage.

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