Anorexia nervosa, commonly referred to simply as anorexia, is a complex eating disorder that centers on a distorted body image and an extreme fear of weight gain. While roughly 85 to 95 percent of anorexics are female pre-teens, teenagers, or adults, boys and men also sometimes develop the disorder. In their quest to limit or lose weight, people with anorexia commonly place severe restrictions on their food or nutrient intake; in turn, these restrictions can trigger the onset of clinical starvation. The consequences of anorexia-related starvation can alter the function of the vast majority of the body’s organs and, in some cases, trigger life-threatening or fatal health complications.
Starvation Basics
To function properly, your body relies on the presence of a substance called glucose, which circulates in your bloodstream and supplies your cells with an ongoing source of energy. Under normal circumstances, in order to maintain your blood glucose levels, you must consume a certain amount of sugars and other carbohydrates as part of your daily diet. Starvation sets in when your body receives far too few sugars and carbs for its ongoing glucose needs, or when it fails to properly absorb and use the available sugars and carbs in your diet.
The effects of starvation take hold in three separate stages. In the first stage of the condition, your body will try to offset the lack of dietary glucose sources by burning a form of reserve glucose, called glycogen, which is stored in the liver. If this stage lasts for more than a few hours, your body will also start converting extra fat and protein into glucose. In the second stage of starvation, your body will primarily rely on converted fat reserves for its glucose supply; if this stage lasts for more than a week, your brain will also start relying on another source of energy indirectly derived from fat, called ketone bodies.
If you deplete all of your fat reserves, the third stage of starvation will begin. During this stage, your body will start to cannibalize the protein in your muscle tissue for energy. If you don’t get enough food at this point, your body will also start to burn off the proteins that control its most basic cellular functions.
Heart-Related Effects
In your circulatory system, anorexia-related starvation can trigger an abnormally slow heartbeat and/or abnormally low blood pressure. It can also trigger a general reduction in your heart’s ability to perform its job effectively. While all of these effects can significantly degrade your health, the main heart-related danger of starvation is the onset of an irregular heartbeat, a condition known formally as arrhythmia. Even in cases where an anorexic has not yet lost extreme amounts of weight, the heart instability generated by an arrhythmia can lead to sudden, unexpected death.
Electrolyte and Bone Effects
Anorexics can also die suddenly as a result of imbalances in critical minerals called electrolytes, which include calcium, sodium, phosphorus, magnesium, and potassium. You rely on these minerals for basic functions such as normal control of your muscles and blood pH, as well as your system-wide fluid balance. In part, anorexia-related electrolyte imbalances result from the clinical effects of nutrient depletion and starvation. Many anorexics worsen starvation-related electrolyte problems by engaging in vomiting or other purging behaviors that expel significant amounts of electrolytes from their bodies.
In addition to acting as an electrolyte, calcium plays a critical role in forming and maintaining bone throughout your skeletal system. In anorexics and other people experiencing starvation, lack of sufficient nutrient intake can lead to significant loss of the calcium in bone tissue and a loss of normal bone density. In turn, these changes set the stage for osteopenia and osteoporosis, two conditions defined by advancing bone thinning and bone brittleness. In some cases, heightened risks for bone fracture are lifelong problems for anorexics, even if they overcome their eating-related problems at some later date.
Brain and Gastrointestinal Effects
Fully 25 percent of your body’s normal glucose supply is used to fuel your normal brain function. When starvation sets in, your body does what it can to preserve your brain’s glucose lifeline. If glucose depletion reaches a critical stage, your brain will also function temporarily with the help of ketone bodies produced in the liver. However, these actions inevitably take a toll on the brain, and the nutrient depletion associated with advanced anorexia-related starvation can lead to shrinkage of brain tissue and a loss of normal brain volume.
Although it may seem counterintuitive, starvation slows your body’s ability to absorb food from your stomach and small intestine. In addition, the condition can severely damage your ability to effectively expel waste from your colon. The combined effects of these changes can produce symptoms that include serious abdominal pain and constipation. Some anorexics also abuse laxatives in a misguided attempt to purge calorie-containing food from their gastrointestinal tracts; these products can worsen the symptoms of both constipation and abdominal distress.
Endocrine System and Kidney Effects
Your endocrine system produces substances called hormones, which act as chemical triggers for vital processes throughout your body. Anorexia-related starvation affects this system in several ways. In teenage girls and women, endocrine problems can lead to a partial or complete lack of normal menstruation. In both men and women, anorexia-related endocrine disruptions can also trigger a slowdown in the thyroid gland, which helps control normal metabolism. In people with diabetes, anorexia-related endocrine problems can increase the risks of death associated with both diabetes and anorexia. Some anorexics experiencing starvation also develop alterations in normal kidney function that can lead to increased urine output, decreased urine output, or death associated with depletion of the electrolyte potassium.
