Anorexia may be caused by bacteria which confuse the immune system, leading it to attack the brain and trigger feelings of personal disgust, scientists have suggested
The theory is the first time that the eating disorder has been linked to a physical infection, in contrast to the traditional view which blames psychological, environmental and social factors.
Experts from Lancaster University and Morecambe Bay NHS Trust in United Kingdom also believe that Irritable Bowel Syndrome (IBS) and Chronic Fatigue Syndrome (CFS) have similar pathologies.
They say it ‘stretches credibility’ to think that such serious conditions are simply the result of mental trauma or psychosocial problems.
The researchers point to the fact that women are far more susceptible to auto-immune diseases – such as pernicious anaemia – where the body’s own immune system begins to attack healthy cells.
Likewise women are around ten times more likely to suffer from anorexia, IBS and CFS suggesting the cause may be similar.
Dr Quenton Wessels, of Lancaster University, said the diseases begin when the body encounters a certain bacteria and switch on an immune response which accidentally begins to attack healthy parts of the body.
“It’s really a case of misidentification,” he said. “The immune system responds to something that is foreign by producing an antibody which then attacks something else.
“Auto-antibodies acting on the brain’s limbic system could induce extremes of emotion including disgust and fear.
“These then become linked, in the minds of adolescent girls, to culturally determined ideas of what is, and what is not, the ideal body shape and size. It is then a small step for disgust and fear to be directed to food and obesity which the fashion industry currently demonizes.
“We think specific bacteria is setting it off. It is almost like the microbes within you can determine you mood, which is profound in itself.”
Previous research has suggested that IBS and CFS may have a bacterial origin. The onset of IBS commonly follows an episode of infectious diarrhoea while chronic fatigue syndrome can be triggered by infectious mononucleosis and viral hepatitis.
Writing in the journal Medical Hypotheses, Dr Jim Morris from theUniversity Hospitals of Morecambe Bay NHS Trust, Dr Sue Broughton and Dr Wessels from Lancaster University said current explanations for why the diseases occur are unsatisfactory. “Psychological factors might be important, but are unconvincing as the primary or major cause,” they write.
“There might, for instance, be an increased incidence of physical and sexual abuse in childhood in those who go on to manifest functional disorders.
“It is easy to see how this could influence symptoms in adults but it stretches credulity to imagine abuse as the sole and sufficient cause of the functional disorder.”
If proven, the fascinating hypotheses opens up new avenues for medication and potentially cures for disorders which have, historically, proven difficult to treat. For example, transfusing immune cells from the blood of healthy people could help reverse the most severe cases of anorexia.
Changing bacteria in the gut to remove the original source could also calm down IBS and CFS.
Now the team want to test their theory on animal models to find out if they can spot the bacteria responsible.
Dr Wessels added: “If we can isolate the culprits perhaps we can restore the correct bacterial balance. We hope to move into the lab over the summer, and hopefully have an answer by the end of the year.”
A study published last week suggested that anorexia was more prevalent in single sex girls schools and may be socially contagious if not physically contagious.
Psychiatrist Dr Jeffrey Liberman, director of the New York State Psychiatric Institute said: “What makes people develop eating disorders is still unknown. As to whether it could be socially contagious, I think the answer is yes.”
The new research was welcomed by charities.
Andrew Radford , the Chief Executive of eating disorder charity Beat, said: “Beat welcomes any new research which might add to our knowledge of the causes of and triggers for eating disorders.
“While the cause of an eating disorder is still unknown, current evidence suggests that they result from a genetic predisposition triggered by a particular event in the sufferer’s life. We look forward to hearing more as this research strand is pursued further.”
Source:telegraph