The Dangers of Re-Feeding Syndrome

Re-feeding syndrome is one of the most dangerous and well-known complications from anorexia nervosa. Although the disorder itself does not result in increased mortality, the electrolyte disturbances that occur secondary to this disorder result in cardiac and renal failure potentially causing death. Re-feeding syndrome occurs when the severely malnourished individual begins to increase their caloric intake either voluntarily or through a feeding tube or intravenous line. In a starvation state the body usually breaks down fats and proteins into energy because carbohydrates are depleted first in starvation. Upon increasing caloric intake through re-feeding, a rise in insulin occurs due to an increase in carbohydrates resulting in a sudden shift from fat and protein metabolism to carbohydrate metabolism resulting in an extreme electrolyte imbalance. A severe decrease in phosphate, potassium and magnesium occur, formally known as hypophosphatemia, hypokalemia and hypomagnesemia. Re-feeding syndrome is a medical professional’s worst nightmare when treating an individual with anorexia nervosa as they must monitor fluids, electrolytes and organ function very closely and this syndrome does warrant a hospital admission and may even warrant an admission to the intensive care unit.

Effects of re-feeding syndrome on the heart

Experiments were done during World War II on volunteers who agreed to lose a set percentage of their body weight. It was discovered that the weight loss resulted in low blood pressure and reduction in the size of the heart muscle.

Cardiovascular collapse can occur with re-feeding of the body because it is difficult for the smaller heart muscle to handle the increase in blood volume seen with re-feeding. This can result in heart failure. The first few weeks of re-feeding the body require close monitoring of the cardiovascular system by healthcare providers.

The heart mass can revert to normal with the appropriate weight gain. Electrolyte changes can also lead to abnormalities in the contraction of the heart muscle, particularly from low phosphorus levels. Besides the risk of heart failure with re-feeding syndrome, severe weight loss causes other negative effects on the heart. The heart muscle gets smaller in size, the mitral valve may prolapse, the heart rate slows and the blood pressure decreases.

Fluid can accumulate in the sac around the heart muscle, known as pericarditis. Irregular heart rhythms, known as arrhythmias, can also occur and may even cause sudden death.

Effects of re-feeding on the endocrine system aka the hormonal system

The effects on the endocrine system often result in:

  • Loss of menstrual periods for females
  • Infertility
  • Dangerously low blood sugars
  • Bone loss

The bone loss, diagnosed as osteopenia or osteoporosis depending on severity, increases the risk for fractures. Metabolism slows, along with production of energy and body heat, and growth is arrested.

Effects of re-feeding on the Gastrointestinal System

The gastrointestinal system experiences slowing of the GI muscles, delayed gastric emptying, constipation, impaired colonic transit time and possible hepatitis. There can be more complications if purging behaviors are occurring. Purging by vomiting can cause erosion of tooth enamel and destruction of esophageal tissue with possible tears and bleeding, potentially causing a ruptured esophagus or changes to the tissue lining that increase the risk for esophageal cancer (called Barretts esophagus). Purging by laxative abuse can cause destruction to muscles in the colon resulting in “lazy colon” leading to severe constipation and potential bowel obstruction.

Effects of re-feeding on the pulmonary system

The pulmonary system experiences muscle wasting and decreased pulmonary capacity with starvation. Decreased production of red blood cells, white blood cells and platelets occur. The brain also shrinks in size (cerebral atrophy) with cognitive impairment, peripheral neuropathy, and possible seizures.

Effects of re-feeding on the renal system

Kidney function is impaired by dehydration, but also by excess consumption of water. Overall body muscle wasting occurs. The skin becomes dry and the skin color changes. Loss of hair on the head may occur while lanugo hair (the fine, downy hair on a newborn) may return on the body.