Below is a fantastic post written by Debbie Malakan our intern for the past six weeks.  It is very thorough, interesting and definitely eye-opening as well as well written.

Eating disorders have serious, potentially life-threatening physiological and psychological consequences. While chronic restriction of food intake can negatively affect nearly all of the body’s systems, some of the most significant harm can occur in the brain. Starvation results in both structural and functional neurological changes that are described below.

Physical Changes

Brain imaging studies have demonstrated that starvation can result in structural changes in the brain. In severe cases of malnourishment, the brain appears similarly to that of a person with Alzheimer’s disease. The brain utilizes approximately 20% of the body’s total expenditure. Therefore, a starving body is unable to protect the brain and maintain its function.

Severe nutritional restriction results in enlargement of the brain’s ventricles – the cavities containing cerebrospinal fluid – due to the atrophy of surrounding brain tissue. Significant loss of brain volume occurs in the white matter, which is responsible for connecting various regions of the brain and determines how quickly information can be processed, as well as in the gray matter, which is associated with concentration, intelligence, personality, emotions, and creativity. Research suggests that gray matter losses are significantly greater in adolescents with acute eating disorders, compared to adult patients; however, both populations show significant reductions compared to healthy controls.

One specific region of gray matter, the precuneus, is involved in self-processing and self-reflection and has been shown to be the region most strongly affected by starvation. Reduced precuneus volume is associated with distorted body image (discussed below) and may not be recovered through weight restoration. Studies have also found gray matter reductions in regions of the brain connected with appetite and perception of the body’s sensations, which may contribute to certain characteristics associated with eating disorders.

Although weight restoration promotes partial restoration of neural tissue, decreased brain volume (especially of gray matter) has been shown to persist for years after weight is restored in some individuals. Research suggests that the extent of weight loss is associated with the severity of structural brain abnormalities, and the lowest body mass index reached during illness predicts the extent to which abnormalities can be reversed.

Cognitive Deficits

As a result of severe restriction, cognitive functions become impaired. A malnourished brain may have difficulty concentrating, making decisions, remembering information, or doing problem-solving, planning, or automatic processing tasks. This can impact the ability to perform well at school or work or to carry out basic functions. The cognitive deficits of a starved brain also make it difficult to do the deeper cognitive work involved in healing from an eating disorder and other co-occurring disorders (such as anxiety, depression, OCD, and PTSD). Therefore, the first treatment goals are the renourishment process while teaching the individual coping skills to use during this time until their brain is fed to do the deeper cognitive and emotional work.

Cognitive changes in a malnourished brain also result in illogical thinking, which can manifest as beliefs such as “eating a piece of cake will make me gain weight immediately” or “gluten and dairy are poisonous to my body.” The beliefs are so powerful and feel so real to the individual that any attempt to reason with them will likely be unsuccessful. In addition, cognitive deficits contribute to anosognosia, a term that describes an individual’s inability to recognize that they are sick with an eating disorder. This brain condition is also found in people with brain damage or schizophrenia. The denial of being sick or having a problem that requires treatment may contribute to one’s resistance to getting help.

Furthermore, a starved brain’s cognitive alterations impact social functioning. Studies have found that individuals who consistently restrict their food consumption exhibit less activity of the brain networks responsible for comprehending the thoughts and actions of others. These deficits can have a detrimental effect on social relationships and contribute to social isolation, especially when combined with emotional impairments and the unpleasant moods and behaviors brought on by starvation.

Increased Vigilance and Anxiety

A malnourished brain senses that it is in danger and begins to continuously assess potential threats in its surroundings. Malnourished individuals may experience increased anxiety and fear, and increased rigidity/inflexibility in their thinking processes as a result of this heightened risk monitoring. An adolescent with a starved brain can feel genuinely terrified at the thought of eating a meal or snack, resulting in drastic measures being taken to avoid having to do so (e.g., hiding food, lying to parents, or making threats).

Additionally, sleep may be prevented or disrupted by obsessive thoughts about daily food intake and/or exercise, which is part of the starving brain’s safety assessment. The body is unable to fully rest if it is constantly in fight-or-flight mode. Individuals with eating disorders often lie awake at night for hours obsessing over the foods or calories they consumed that day or planning out their food intake and calorie burning for the following day(s). This contributes to their chronic mental, physical, and emotional exhaustion.

Altered Chemical Signaling

Neurotransmitters are the chemical messengers that transmit signals between our nerve cells, allowing our body systems to perform their functions. Research suggests that individuals with eating disorders suffer from neurotransmitter disturbances, which may contribute to appetite dysregulation and disordered thoughts and behaviors.

Prolonged dietary restriction is associated with the dysfunction of two neurotransmitters in particular, dopamine and serotonin. The disruption of these neurotransmitters can potentially affect mood, appetite and satiety, impulse control, motivation, reward, and other psychobiological factors. Specifically, the reduction in serotonin levels that results from starvation and weight loss causes a dysphoric (depressed) mood in response to eating, anxiety in response to palatable foods, and improved mood in response to dietary restraint. Dopamine dysfunction is associated with a disturbance in reward mechanisms for individuals with eating disorders, contributing to the potential for excessive exercise tendencies, altered pleasure responses to food, and practices of extreme self-denial. Both of these impaired signaling systems are thought to promote the ongoing pursuit of starvation.

Reduced Production of Sex Hormones

In response to starvation, adolescent and adult bodies recognize that reproduction is unsafe. In a process called hypothalamic hypogonadism, the hypothalamus (a brain region involved in maintaining steady physiological conditions) reduces the production of sex hormones back to preadolescent levels. This results in low estrogen levels in females and low testosterone levels in males. Reduced estrogen levels can lead to a delayed first period for younger teen girls, or amenorrhea (cessation of menstrual periods for three or more months) in females who were previously menstruating. Reduced sex hormone levels can also contribute to irreversible bone density loss in both sexes (discussed more below).

Dysregulation of Hormones

As a result of malnutrition, dysfunction of other hormones regulated by the hypothalamus can occur, including cortisol(our stress hormone), growth hormone, and insulin-like growth factor-1 (IGF-1), both of which regulate growth and metabolism. Anorexia nervosa is characterized by elevated cortisol levels in the blood, which increase in response to the physiological stress associated with malnourishment and weight suppression. As adaptive responses to chronic starvation, growth hormone resistance develops in the liver, preventing calories from being used for linear growth, and IGF-1 concentrations quickly decrease. Elevated cortisol levels, in combination with low sex hormone levels, low IGF-1 levels, and growth hormone resistance, contribute to reduced production of new bone and subsequent bone density losses. This, in turn, significantly increases an individual’s risk of bone fractures, potentially leading to consequences such as the end of an athletic career and/or sports scholarship, disability, chronic pain, or a permanently curved upper spine.

Altered Reward and Hunger Signals

In individuals with eating disorders, studies have demonstrated abnormal brain activity and increased anxiety and/or sensitivity in response to photographs of food, exposure to food, or the experience of eating. Additionally, these individuals show reduced brain signal responses to the administration of nutrients, as compared to healthy controls. These altered neural responses likely promote the continued avoidance of food.

Studies have found that individuals with anorexia show increased activation of the amygdala (the part of the brain that detects fearful stimuli and threats) when feeling hungry, suggesting a fearful emotional response to hunger cues. Furthermore, research suggests that over time, restrictive eating behaviors condition the brain to override hunger cues that normally motivate people to eat, disrupting the connection between the brain and the gut. This gradual disappearance of hunger cues allows malnourished individuals to eat increasingly less food and often makes the renourishment process more challenging both physically and psychologically.

Body Image Distortion

Individuals with anorexia nervosa and other eating disorders often perceive themselves as being fat, when in reality they have dangerously low body weights. Interestingly, they typically have accurate perceptions of other people’s bodies. Research suggests that these individuals have altered activation of the precuneus brain region, which can cause them to overestimate their body size and thus contribute to body image distortions. Additionally, anorexia nervosa is associated with abnormal activation of the insula, a brain region associated with cognitive and emotional perceptions of the body, as well as interoceptive awareness (the ability to identify, understand, and appropriately respond to the body’s internal cues).

A recent theory proposes that individuals with eating disorders are attached to disturbed memories of their own bodies that are not continuously updated after lived experiences, including significant weight loss. These body image distortions are thought to be related to reduced serotonin transmission (discussed above) and result in extreme attempts to control weight and shape. Research suggests that although body image distortions are persistent, they can be improved through treatment and weight restoration in some individuals.

In conclusion, eating disorders alter the brain’s structure and function, which has an impact on a variety of mental processes, including perception, emotions, and thoughts. While weight restoration can reverse some of the starving brain’s characteristics, other features have been shown to persist into the latter phases of recovery. Adequate nutrition promotes not only the return to a healthy body, but also the mind’s emotional and cognitive recovery.

Recovery is possible, let us help you get there!