Scientists have found an unexpected factor about the work of the brain of women with bulimia
'14.07.2017'
Source: Medportal
An MRI scan of the brain of women with bulimia showed that it responds to the same nutritional signals in a completely different way than the brain of women who do not suffer from this disease.
Scientists from the National Medical Center for Children in Washington DC found out this difference about the work of the brain, reports “Medportal".
They conducted a study that found that women with bulimia in the brain areas associated with reflexion had significantly less blood flow than women without eating disorders.
Dr. Brittany Collins and her colleagues believe that overeating is a salvation from negative thoughts during acute stress. People with bulimia nervosa have recurring, rather frequent bouts of overeating that they cannot control. During these episodes, they consume unusually large quantities of food, and then try to compensate for this with forced vomiting, starvation, excessive exercise, or the use of laxatives.
It is believed that over time, bulimia inevitably adversely affects health. It can lead to chronic inflammation of the laryngeal mucosa, erosion of the tooth enamel, indigestion, severe dehydration, and intestinal problems. It can also lead to an imbalance of electrolytes, which, in turn, greatly increases the risk of stroke and heart attack.
In the US, bulimia affects about 0,3% of the population, or three adults per thousand, and more likely to have bulimia in women than in men. Although the number of men with RPP (eating disorder) has significantly increased lately, they, overeating, then exhaust the body with excessive physical exertion, which, in principle, is one of the options for bulimia (bigorexia).
Escape from negative self-perception
There is a widespread working theory that overeating helps people with bulimia avoid self-critical thinking during times of stress, allowing them to focus instead on something concrete and present, despite the fact that it may hurt in the long run.
In her article, Dr. Collins and her colleagues explain how this theory is supported by several studies showing that stress and negative emotions tend to occur before the onset of overeating, and that negative emotions tend to decrease dramatically after an attack.
More recently, scientists have become interested in studying brain function in order to find explanations for bulimia.
“To our knowledge, the current study is the first to investigate neural responses to food signals after a stressful event in women with bulimia nervosa,” says Dr. Collins.
There is no difference in stress levels and food cravings.
During the experiment, scientists scanned the brains of 20 women, divided into two groups, one of which (10 man) was susceptible to bulimia, and the second - no. First, both groups fed the same food, and then began to show a series of photographs. At first, these were photos of a neutral content, such as images of houses, trees, or leaves, then they were replaced by images of foods high in fat and sugar, such as ice cream, pizza, or cake. To introduce both groups into a state of stress, the participants in the experiment were offered a number of impossible mathematical tasks that made them nervous and feel helpless before the problem, and then reduced their anxiety, and then asked to assess the level of stress and cravings for the products shown in the pictures.
Women in both groups equally described the time of the beginning and end of stress, equally estimated its level, as well as the level of craving for food. However, MRI scans showed a different picture in the two groups.
MRI scan of the brain talks about the differences
While self-determined levels of stress and craving for food were largely similar for both groups, their MRI scans of the brain showed a completely different picture.
MRI of the brain in women with bulimia showed that when they looked at pictures of food after a stressful task, they had a decrease in blood flow through the preclinical portion of the parietal lobe on the inner surface of both hemispheres of the brain, which is an area associated with self-esteem and reflection. For women without bulimia, there was an increase in blood flow through this area of the brain, regardless of whether they looked at food pictures or neutral images. This result surprised researchers.
Therefore, a team of scientists again conducted an experiment in another group of 17 women with bulimia. They found that the results were the same: as before, women reported increased levels of stress after a stressful task and stated an increase in food cravings. And, most importantly, an MRI scan also found the same reduced levels of blood flow in the preclinium during the exposure of food signals after a stressful task.
Scientists have considered that both experiments confirm the mechanism of brain work that they proposed, which distracts attention from the subjects' negative self-analysis to something concrete in the present, namely, to food signals. It is through this mechanism that women with bulimia distract themselves from the stress of eating.
Dr. Collins and her colleagues suggest that the results of their study should be considered preliminary.
"Our results are consistent with the characterization of overeating as an escape from self-criticism and support the emotion regulation theory, which suggests that women with bulimia are distracted from self-judgments by negative thoughts about performance or social comparisons and shift the focus of their thinking to more specific stimuli such as eating." - notes Dr. Collins.
As the researchers say, the data will help women to control the mechanism of overeating, which is included with the slightest increase in stress levels. According to scientists, it is necessary to organize the training of such women in the regulation of basic behavioral skills and desires, and some of them may need drug therapy. In any case, after the mechanism of bulimia has become clear, scientists will find a way to help women get rid of this disease.
