Friday, November 18, 2011

Studies find beneficial health effect for probiotics

Two studies have independently shown that probiotics, dairy products with added bacteria, could have clinical relevance after all. While many studies have failed to produce a positive outcome of probiotics treatment, scientists from Utrecht University recently found that they can reduce the severity of pancreatitis, which is characterized by severe inflammation of the pancreas by using a bacterial shake. In addition, American researchers in St. Louis revealed that pre-treatment with probiotics ameliorates the damage caused by radiation therapy.

Both studies were performed in animals. In Utrecht, rats were given daily probiotics, and treatment started five days before contracting acute pancreatitis, which often leads to death. In the small intestine, unusual high numbers of a bacterial strain called CRIB was found. In addition, its presence was correlated with a decrease in organ infection, less infection in the affected pancreatic tissue, and a decrease in the host's immune response. Reduce in death count was not reported.

The researchers in St. Louis performed their experiments on mice, and noted that pre-treating them with probiotics before radiation therapy was beneficial for their health. Radiation therapy is often used to treat cancer, but is not very specific: surrounding, healthy tissue can also get damaged. The scientists specifically assessed the top layer of cells in the gut, which is important to let the gut function properly in its absorption of nutrients. This epithelial cell layer was found to be receiving less damage when the abdomen of the mouse was irradiated, when mice were pre-treated with probiotics. Treating them after radiation therapy failed to produce a beneficial effect. For the St. Louis study, it was LGG, a common bacteria also found in our yogurts, that produced the beneficial effects.

There is a continuous search to find a working mechanism behind a beneficial health effect of probiotics. While this has not been found yet, some scientists have opted that probiotics decrease inflammation, and thus organ damage, by affecting the so-called Cox2 and prostaglandins pathway. This is a known pathway in inflammation, and several mild anti-inflammatory drugs, the NSAID's of which aspirin is one, affect this pathway.

Especially the study from Utrecht University, that found a beneficial effect in pancreatitis, is remarkable. A few years ago, this university performed a clinical trial with human patients, but probiotics treatment actually increased pancreatitis-induced deaths. This was attributed to the fact that the disease can cause the gut to start 'leaking', which renders bacteria able to travel to other parts of the body, where they can become harmful, instead of beneficial. Therefore it remains to be seen whether the recent animal study can be reproduced in humans, though it is unlikely they will receive permission to perform another human study in pancreatitis patients.

The initial enthusiasm about dairy products containing alleged 'healthy bacteria' has died out over the last couple of years, following the failure of backing up certain health claims with scientific proof. This might be a step in a different direction, but it all depends on whether scientists can show a beneficial effect in humans. Recently, a study showed that bacteria in probiotics are able to affect the host's natural gut flora. They found that the ingested bacteria passed right through the gut, but in the process affected their native counterparts. There were no functional differences noted, though.

Bacteria play a big part in our body, which is often neglected. Instead of being beneficial, gut bacteria can also cause disease, just like external pathogens would be able to do. That is why much more research needs to be done to unravel the secrets of our special relationship with these micro-organisms.

All in all this still does not mean you should go buy the dairy products that are being advertised on television.

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