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Pesky little bug could hold clue to eating disorders

Posted Feb 20, 2010

Have we been looking in all the wrong places for the cause of eating disorders?

Common culprits include social pressure to be thin, media drum-beating about the perfect body, anxiety, depression, low self-esteem, trauma in the family, family history of eating disorders, a history of being teased, sexual or physical abuse. And then there is biology.

The search for underlying causes continues. As explained by the National Association of Eating Disorders, "Scientists are still researching possible biochemical or biological causes of eating disorders. In some individuals with eating disorders, certain chemicals in the brain that control hunger, appetite, and digestion have been found to be imbalanced. The exact meaning and implications of these imbalances are under investigation."

Enter NuBiome, a company founded in 2009 to develop therapies, including probiotics (beneficial bacteria) that interfere with disease-causing bacteria found in the gastrointestinal tract, focusing on autoimmune conditions. The company founders all have seen or had family members who got sick with autoimmune diseases. That includes bulimia and anorexia.

"The paradigm's got to change," said Brian Lue, a NuBiome researcher. In a paper he delivered recently, Lue explained how people used to think that stomach ulcers were caused by stress and dietary choices.

"It took a couple of remarkable Australian scientists named Robin Warren and Barry Marshall over a decade of research and human trials to dethrone the stress and diet paradigm that the medical community strongly believed at the time. It has now been proven that stomach ulcers are actually caused by a pesky little bug that looks like a corkscrew called Helicobacter pylori, or H. pylori for short. Although they could see the bug with a microscope, no one believed H. pylori was the culprit until Marshall made a drink filled with H. pyloris and swallowed it, and in doing so gave himself stomach ulcers. He then treated himself with antibiotics to kill the bugs and cure the ulcers. This result was so ground-breaking and unexpected that they were awarded a Nobel Prize in Medicine in 2005."

Since then, some patients have reported that consumption of the right probiotic bacteria relieves their symptoms.

Lue and others at NuBiome are looking at microbial connections to Crohn's disease, which can have symptoms outside the gastro-intestinal tract, such as painful itching and joint swelling.

NuBiome's clinical activities are headed by Dr. Frederick Westall, who headed laboratory work at the Jonas Salk Institute and more recently discovered possible bacterial causes of multiple sclerosis.

Lue explains, "A normal person with a normal immune system may have a rare event in their intestine and this changes the way the normal bacteria in their gut die and break up into fragments. Their immune system then finds a specific piece of the bacteria that looks like a piece of the insulation on their nerves. Now, when the immune cells find that piece of insulation on the nerves, bad things start to happen. The body's immune system turns against nerve insulation because it "thinks" that they are foreign bits of bacteria. In the process it ends up destroying its own tissue because it confuses body tissue with that of the bacteria. This is what an autoimmune disease is. In the case of multiple sclerosis, the insulation on the nerves is attacked by the person's own immune system."

How does all this relate to eating disorders?

Lue refers to a 2005 paper in the Proceedings of the National Academy of Sciences by Serguei Fetissov, who identified specific antibodies in people with anorexia and bulimia nervosa. These antibodies disrupted the normal hormonal systems of the brain, particularly
the part of the brain that is responsible for appetite control and the stress response.

Lue writes, "This seems to correlate with the changes in eating habits that defines bulimia and anorexia. The authors of the study suggested that the autoimmune response could be triggered by pieces of several types of bacteria in the gut mimicking the brain hormones. Pieces of H. pylori, the stomach ulcer bacteria, and E. coli are some of the likely suspects."

Now, no one knows if eating the right yogurt will help quell the symptoms of anorexia and bulimia, but when Lue asked about my daughter's early exposure to antibiotics, my brain engaged. Lisa had chronic ear infections and took a lot of amoxicillin. It will be fascinating to follow this research.

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