A new post on the "You Must Be Hungry" blog at Psychology Today looked at the relationship between eating disorders and autoimmune diseases, as well as potential treatments in the form of probiotics (healthy bacteria, like the kind in yogurt). Writes author Shelia Himmel:
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.I'm a long way from saying that yogurt is some magical cure-all for eating disorders (though I do loves me some yogurt), but the research is interesting.
"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.
...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."
I had previously downloaded the 2005 Fetissov paper that Himmel mentioned in her blog post, titled "Autoantibodies against neuropeptides are associated with psychological traits in eating disorders," and re-read it for this post. The researchers knew from previous research that people with AN and BN had antibodies to α-melanocyte stimulating hormone (Fetissov et al, 2002), known as auto-antibodies because they were antibodies against "self" proteins, and the authors of the 2005 study note that:
melanocortin peptides involved in appetite control and the stress response. In this work, we studied the relevance of such [auto-antibodies] to AN and BN. In addition to previously identified neuropeptide autoAbs, the current study revealed the presence of [auto-antibodies] reacting with oxytocin (OT) or vasopressin (VP) in both patients and controls.Which is interesting, when you look at the roles of both oxytocin and vasopressin and consider that difficulties with social relationships and stress, respectively, are pretty common in eating disorders. What is also interesting from this study are the differences in auto-antibody levels in AN and BN. In AN, higher levels of auto-antibodies were correlated with higher scores on the Eating Disorder Inventory-2 (meaning higher levels of ED psychopathology), while in BN the opposite was true: higher levels of auto-antibodies meant lower levels of ED psychopathology, and vice versa. (If I'm reading the statistics wrong, please someone let me know- it's been a long time since I had to puzzle through dense biostatistics jargon.) What this difference ultimately means is beyond me, although I hope more research will look into the subject.
At the end of Himmel's blog post, she mentioned that a NuBiome researcher asked about her daughter's (who had anorexia and bulimia) childhood exposure to antibiotics, and Himmel recalled that her daughter had frequent doses of antibiotics. Granted, so did I, for frequent lung infections aggravated by asthma that left me with a 10-pack-a-day smoker's cough at the age of 6. However, antibiotics were peddled like candy when I was younger, and furthermore, EDs existed long before penicillin. Nor was I able to find any research indicating a link between antibiotics and the onset of eating disorders.
Still, the research is interesting and thought-provoking, and I'm curious to see more. I'm also getting a strange urge to hit the dairy case, so if you'll excuse me...