Wednesday, 31 August 2011

Food and irritable bowel syndrome

Irritable bowel syndrome (IBS) has always seemed like a bit of an odd term to me. Odd because whilst it is used to describe various symptoms related to the bowel, 'irritable' to me implies angry and annoyed. Assuming that a similar meaning is denoted for IBS, various notions perhaps acquire new meaning. If for example, we assume that the gut is the second brain, and our first brain (the one in our head!) is the part of us that becomes irritable, angry or annoyed in response to whatever, then one can see some sense in its use when applied to the gut.

I digress. There is quite a lot of speculation as to what causes IBS and what are the most effective ways of reducing or managing symptoms. Outside of psychological factors such as stress, diet and food have been consistently related to some cases of IBS and the suggestion that sensitivity or intolerance might be tied into symptoms. I wrote a post about this not so long ago following the publication of quite an important piece of research where non-celiac gluten intolerance seemed to be linked to some cases of IBS. Removing gluten, or rather reintroducing gluten after having previously been excluded from the diet, seemed to be linked to the appearance of various IBS symptoms over placebo.

A recent article adds to the dietary connection. The paper by Carroccio and colleagues* suggested that a quarter of their participant group were found to have a food hypersensitivity to cow's milk protein and/or gluten wheat protein. Furthermore levels of tryptase, an enzyme normally released as part of an allergic-immune response, and fecal eosinophil cationic protein (ECP), related to inflammation, were higher in those participants with IBS and food hypersensitivity. This indicating some possibility of identifying those cases of IBS with a potential dietary effect involved.

Whilst complicated, dare I say spectral, conditions such as IBS are never going to be caused by one factor and one factor alone, there is some reliable evidence emerging implicating a dietary effect as being involved. Much like lifestyle and stress-reduction treatments and pharmacotherapy, such a dietary effect if linked, provides another possible intervention route to potentially alleviating symptoms, at least for a proportion of those affected.

* Carroccio A. et al. Fecal assays detect hypersensitivity to cows milk protein and gluten in adults with irritable bowel syndrome. Clinical Gastroenterology & Hepatology. August 2011.

Wednesday, 24 August 2011

Metabolic syndrome and gluten

I am pretty used to hearing about and using the word 'metabolic' in my day-to-day work. In this context, metabolic refers to a few things: a metabolic pathway, describing some chemical reactions leading to an end compound or other endpoint process; or an in-born error of metabolism, describing some genetic 'malfunction' predominantly with enzymes or enzymatic reactions.

A new term has started to creep into my dictionary over the past few months or so, metabolic syndrome. Whilst sounding like it should have something to do with the other uses I described, metabolic syndrome actually describes a set of risk factors which might predispose a person to subsequent problems of coronary artery disease, stroke and type-2 diabetes. The main risks taken from the various descriptions tend to include:

Why might metabolic syndrome be important to this blog? Well, because of this paper by Garcia-Manzanares and colleagues* published in the World Journal of Gastrointestinal Pathophysiology which reported on a case study of a woman presenting with the features of metabolic syndrome alongside coeliac (celiac) disease, and what happened when a gluten-free (GF) diet was installed.

I am sure that readers can guess what I am going to say. The woman, who was overweight, presented with high cholesterol and triglycerides, alongside iron deficiency was eventually found to present with comorbid metabolic syndrome and coeliac disease. Installation of a GF diet seemed to solve the iron problems (as one would expect it would in coeliac disease) but also seemed to positively affect dyslipidemia and measured glucose levels. In short, some of her metabolic disease risk factors seemed to be reduced.

It would of course be easy to say that all the effects were from the GF diet (and indeed I might try and further that view) but stepping back there are quite a few potential confounders which might also have played a hand in the results. So things like the fact that entering onto a GF diet probably quite fundamentally changed her diet anyway; out goes the wheat and other gluten-containing grains yes, but in comes perhaps more protein, more vegetables and fruits, more dairy products? What about any additional supplementation for all those vitamins and minerals that might be lost from the diet? I dare say that she was also told to do a little more exercise to help reduce her weight burden also. Lots of confounders which could potentially affect her metabolic disease risk factors.

Having said all that, there has for quite a while, been some discussions about how a GF diet might potentially be linked to lots of different things outside of just managing coeliac disease and other gluten sensitivities. I am not going to go down the autism or schizophrenia route too much, but there are some suggestions of potential effects in these areas and for related conditions particularly the health effects of components of our modern diet such as carbohydrates and what happens when you reduce the carbs. Another quite interesting thought (as least to me!) is whether or not the link between gluten removal and subsequent altered gut permeability in coeliac disease might also tie into some of the effects noted. So does a better gut barrier function promote better lipid and glucose measures?

I am going to stop there as I fast approach the limits of my competence in an area which is screaming out for further investigation. I state my disclaimer that I am not providing any medical or dietary advice from the research discussed in this post - that's the job of your healthcare professional, and I strongly suggest you consult them before making any changes to diet or anything else.

* Garcia-Manzanares A. et al. Resolution of metabolic syndrome after following a gluten-free diet in an adult woman diagnosed with celiac disease. World Journal of Gastrointestinal Pathophysiology. June 2011.

Thursday, 18 August 2011

Milk, gut bacteria and coeliac disease

Coeliac disease (CD), that exquisite sensitivity to dietary gluten, has long been the focus of quite a bit of research. That's not to say that in all those years we don't know a little bit about CD; some of its genetics, its diagnostic markers, its treatment, but there are still lots of things we don't know about CD as well as the various non-coeliac forms of gluten sensitivity which seem to be emerging.

When it comes to early markers or risk factors for CD, there are quite a few already in the research literature. I covered some of them on one of the sister blogs (here and here). Indeed the last link including this paper on your choice of entry into the world and subsequent gut bacteria, provides a good example of what might affect your start-up gut bacteria and potentially your subsequent risk of things like CD on the back of my previous post.

Enter a new potential player into the world of CD risk; surprisingly enough from your earliest form of nourishment post-partum, milk. The research by Sanchez and colleagues* postulated a connection between the genetic risk of CD and the type of bacteria from the Bacteroides species identified in fecal samples from infants with a parent with CD. An overview of the results can be found here.

The results from this study point towards two important points:

  • Genetic risk of CD as measured by the HLA-DQ genotype might influence the composition of the gut bacteria.
  • The type of early feeding practices (breast vs. bottle) might also influence gut bacterial composition at different times of infancy.

Whilst there are some interesting links made in this and other studies in this area, as always we need to be cautious in jumping to conclusions. Several authors have speculated that the type of early feeding pattern might alter the risk of developing CD. The evidence is however far from conclusive; indeed whilst there may be some effect in delaying the onset of CD, delay does not mean the condition will not develop. Indeed we will have to wait for studies like this one to formally reports before we can draw any firmer conclusions.

Still what studies like this offer is an insight into the complicated world of genetics and environment in conditions like CD and how our gut bacteria might well be king-maker (or at least a prince/princess) when it comes to conferring risk and protection against lots of conditions.

* Sanchez E. et al. Influence of environment and genetic factors linked to celiac disease risk on infant gut colonization by Bacteroides species. Applied & Environmental Microbiology. August 2011.

Tuesday, 16 August 2011

Can a gluten-free diet affect gut bacteria?

For those who have stumbled across this blog on the wide open plains of the Internet, I have a bit of interest in all things gluten-free. It is a professional interest and has been for quite a few years, as various colleagues and I have been looking at whether a gluten-free (GF) diet might show some effect on behaviour, and in particular behaviours commonly associated with autism spectrum conditions. We don't have a definitive answer by the way, but do suspect more than a passing association between diet and some cases of autism.

For those of you who perhaps already know of my interest and are thinking 'change the record mate', this post (this blog) is not going to rehash material from its sister blog, Questioning Answers, at least not on this occasion, but rather take a slightly different perspective. This post is tied into this study by Nistal and colleagues* on what happens to gut bacteria populations in coeliac disease when a GF diet is/is not in place. One of their findings was that gut bacterial populations differed (in adults) according to whether or not a GF diet was being applied.

This is not the first time that coeliac disease has been looked at in terms of the GF diet and gut bacterial populations. Indeed the effects of the GF diet seem also to be present outside of coeliac disease, depending on where you look for your bacterial colonies in the gut.

To me this is an interesting finding. Interesting because it suggests that our diet, much like various medications, can affect the trillions or so of gut bacteria that colonise us. Indeed comparative studies looking at diets in different parts of the world outside of coeliac disease have shown pretty much the same thing: what you eat affects your gut bacterial populations. The knock-on effects of this... to be discussed in subsequent posts.

* Nistal E et al. Differences of small intestinal bacterial populations in adults and children with/without celiac disease: effect of age, gluten diet and disease. Inflammatory Bowel Diseases. August 2011.


As per the headlines, this is a blog about your gut, your gastrointestinal (GI) tract, your intestines. This blog is a place to discuss various strands of research about the gut related to all sorts of different aspects and conditions ranging from how the gut works to gut bacteria to gut barrier function to conditions associated with the gut.

Where and what is your gut (as if I have to ask)? Well just in case you don't know, here is a link to a bit of a description.

Please keep all comments on blog posts cordial and polite and no swearing or vulgarity please. I hereby declare that no medical advice will be given or intended from this blog. If you think you have a problem with your gut (or any other body part), go to your doctor, don't rely on blogs!