Saturday, 28 January 2012

Greens, glutathione and the mucosal barrier

'Eat your greens' is a phrase most of us will have heard on several occasions when growing up. I have to admit to being a bit of a 'goody two-shoes' in this respect, having had a lasting affection for things like Brussels sprouts and broccoli. Indeed, sprouts still tend to be on my menu several times a week (boiled with a drop of Greek olive oil).

I say all this because an interesting article published a few years back has caught my eye recently. The paper by Hoensch and colleagues* (open-access) looked at the various factors potentially affecting the functioning of the gastrointestinal glutathione system with some interesting observations.

I will admit that glutathione (GSH) is something which I am becoming very interested in at the moment. Over on my autism research blog, I recently discussed the pretty remarkable findings emerging in some cases of autism with regards to plasma GSH which might (might!) eventually have some diagnostic usefulness in combination with other factors. The Hoensch paper talks about GSH levels in the upper gastrointestinal mucosa and how factors such as diet, some medications and even gender seemed to affect levels of GSH and accompanying enzyme activity (glutathione S-transferase, GST).

The particulars:

  • Biopsy pinches taken from two sites (antral and duodenal mucosa) for 202 adults (104 males: 98 female) undergoing endoscopy were analysed for GSH and GST activities. Various background information was also taken from participants including details of family history, medication and current dietary habits via a food frequency questionnaire.
  • The findings: different biopsy sites reflected different levels of GSH and enzyme activity. Female participants showed higher levels of GSH and GST activity in their antral mucosa samples than males. High intake of vegetables (more than 3 days a week) seemed to enhance aspects of GST activity.
  • A subsequent author reply to a suggestion that Helicobacter pylori infection might also have had an effect suggested that indeed, one aspect of GST activity was negatively affected by H.pylori infection.

Bearing in mind that GSH and its related sub-systems represent an important part of our defences against those dastardly free radicals among other things, making sure that the system is in tip-top condition is probably quite important. I don't want to make sweeping gender generalisations but the fact that females seemed to be in a slightly more advantageous position compared with male participants leads me back to some interesting work on the fragile male. Having said that, let's not be too defeatist here; greater vegetable consumption seemed to have an enhancing effect as per other results so one could argue, guys in particular, eat more greens - especially more brassica vegetables to support your mucosal antioxidant defence system.

* Hoensch H. et al. Influence of clinical factors, diet, and drugs on the human upper gastrointestinal glutathione system. Gut. 2002; 50: 235-240.

Friday, 13 January 2012

Gut bacteria and heart health?

Happy (belated) New Year! Welcome back to Gutness Gracious Me in 2012. I start this year with a post on something pretty central to the ethos of this blog: gut bacteria.

I should perhaps first apologise to Alex Gazzola (#HealthJourno) who very kindly asked if I would be discussing the new Codex standards for labelling foods and gluten-free and the 20 parts per million threshold introduced. I did say I would have a look at this and I am still looking. I do however think that Alex has done a wonderful job of covering this topic on his own blog (see here) as per the reader response he has received.

Back to task. Despite being only 13 days into the New Year (Friday 13th...mmm?), already the research is coming thick and fast. Over at my Questioning Answers blog, the big news recently has been on the bacteria Sutterella and its detection via various methods in quite a few biopsy samples from children with autism and gastrointestinal (GI) issues. I say big news but in among the very detailed explanation of how that team came to find Sutterella, the main story for me is the suggestion that gut hyperpermeability in some cases of autism might be a route through which the immune system meets gut bacteria in places it really shouldn't and onwards formulates an antibody response. The template for this is Crohn's disease and leads into some interesting suggestions about whether gut bacteria itself might not necessarily be the bad guy but rather what happens when it is allowed to roam.

The other quite interesting news is from this paper by Vy Lam and colleagues* suggesting that different amounts and varieties of gut bacteria might influence the severity of and recovery from heart attacks in rats. I am well used to seeing papers talk about gut bacteria in relation to GI issues and conditions, even conditions like autism where functional and more systemic bowel disorders have been noted in some cases. This is however one of the first times that I have come across gut bacteria potentially so directly influencing the physical health of an organ like the heart.

So what did the researchers do?

  • Three groups of rats were fed three different types of diet: a standard diet, a standard diet plus quite a powerful antimicrobial (vancomycin) and a standard diet plus a probiotic very aptly named GoodBelly
  • The primary probiotic constituent of GoodBelly is Lactobacillus plantarum 299v quite commonly found in fermented foods like sauerkraut and subject to a few claims. One of those claims is that the bacteria might be able to reduce the production of leptin among other things.
  • Both the vancomycin and GoodBelly supplemented groups showed a decrease in circulating leptin levels (38% and 41% respectively) alongside some changes to gut bacteria as one might expect.
  • The vancomycin and GoodBelly supplemented groups also showed evidence of smaller heart attacks and improved recovery after heart attack compared with the standard diet group.

Whilst the authors describe this as a 'proof-of-concept' study, there are potentially many implications from this work not least that our gut bacteria might do far more than call us home and help digest our food. I have previously (jokingly) referred to gut bacteria as being our 'masters'. Assuming the results from this study are pertinent to humans as well as rats, I might well be offering a sacrifice to 'those who must be obeyed' in the near future.

Should we be surprised that the human body is interconnected? No probably not, although it might take a while and a few more bits of evidence of effect before cardio health care professionals start giving probiotics to help treat (prevent?) myocardial infarction (please note I am not giving any medical advice about this). Going back to the Sutterella post and the proposed link between bacterial translocation and gut permeability, I do wonder whether research should also be looking more closely at gut permeability and lots of other conditions just to see if findings such as these might provide a few more clues about health and illness.

*Lam V. et al. Intestinal microbiota determine severity of myocardial infarction in rats. The FASEB Journal. January 2012