Refeeding Syndrome

By | June 8, 2022

Refeeding Syndrome (RFS) is a life-threatening condition that can occur with refeeding after a long period of starvation. It is characterized by a mineral metabolism disorder with the occurrence of edema and heart failure. To prevent refeeding syndrome, after a period of malnutrition, food intake should be slow and gradual under medical supervision.

What is Refeeding Syndrome?

The syndrome was first observed after the end of World War II, when Japanese prisoners of war and inmates of Nazi concentration camps suddenly developed severe symptoms of heart failure with edema after eating normal amounts of food. Many deaths are due to the consequences of refeeding syndrome that has subsequently occurred. For meanings of mesenteric infarction, please visit

Today, this condition often affects patients with anorexia nervosa after resuming nutrition. It was observed that parenteral nutrition (venous infusion of glucose) is particularly predestined for the development of a refeeding syndrome. Oral food intake or artificial nutrition via the intestine can also cause the symptoms.

RFS is usually fatal if not recognized and treated in time. The first symptoms of refeeding syndrome usually appear within the first four days after beginning normal feeding. However, the occurrence of the disease also depends on the degree of malnutrition and the length of the previous fasting period.


The cause of the refeeding syndrome is to be found in the development of a complete imbalance in the mineral metabolism due to the resumption of food intake after a long period of starvation. After 48 hours of fasting, all carbohydrate stores in the body are used up. The body now begins to break down fats with the formation of ketone bodies.

The longer the period of hunger lasts, the more valuable minerals and vitamins are lost from the body. If larger amounts of glucose are supplied to the organism after such a period, the pancreas immediately starts producing insulin in order to transport the glucose into the cells for energy production. However, burning the glucose requires some minerals and vitamins. Especially phosphate and vitamin B1 are needed.

The phosphates are a prerequisite for the burning of glucose. The energy store ATP is increasingly generated from them. Vitamin B1 catalyzes the breakdown of glucose. Therefore, the need for vitamin B1 increases at the same time. In addition to the increased absorption of phosphates, potassium and magnesium ions are also absorbed into the cell. The balance between the intracellular and extracellular concentrations of minerals is disturbed.

The minerals are needed in the cell to generate energy, but the body is already suffering from a mineral deficiency due to the long period of starvation. The minerals coming from the extracellular space are now missing there. The imbalance causes the blood vessels to become leaky, developing severe edema. At the same time, the increased insulin formation keeps water in the body. Heart and kidney failure occur.

Symptoms, Ailments & Signs

The refeeding syndrome is characterized by water retention in the tissue (edema), heart failure and an acute deficiency of vitamin B1. Vitamin B1 deficiency induces metabolic acidosis, cardiac insufficiency and neurological deficits. At the same time, the concentration of sodium in the intercellular space increases. States of confusion, low heart rate and weak breathing occur. Eventually, heart and kidney failure occur.

An important finding is hypophosphatemia. The cells lack phosphates for energy production. As a result of the phosphate deficiency, the striated muscle fibers break down (rhabdomyolysis), the red blood cells break down (hemolysis) and breathing is reduced. Hypomagnesemia simultaneously causes cardiac arrhythmia, ataxia, tremors and convulsions. Eventually, hypokalemia is the cause of cardiac and respiratory arrest. Platelet and leukocyte disorders also occur.

Diagnosis & course of disease

Patients at risk who could develop a refeeding syndrome should be identified even before artificial nutrition is given for anorexia nervosa. Not all re-fed patients develop RFS. The risk depends on the lack of minerals and vitamin B1. The condition of the internal organs also plays a major role. A well-trained team ensures that refeeding syndrome is recognized in good time.

Before refeeding, the hydration status should first be checked and normalized. Pulse and blood pressure also require close monitoring. A daily body weight check provides information on whether the increase is pathological (due to water retention) or physiological due to improved nutritional status. During refeeding, constant monitoring to control potassium, magnesium, sodium and phosphate is necessary in order to be able to intervene to regulate. Kidney values, calcium and plasma glucose should also be constantly monitored.


If there is a refeeding syndrome, this is in most cases accompanied by serious health complications. Typical of the disease are cardiovascular problems, which in the most severe cases can lead to heart failure. This is accompanied by water retention in the tissue – edema develops and causes discomfort and pain. In addition, a vitamin B1 deficiency occurs, which can worsen the cardiac insufficiency and also leads to neurological deficits and metabolic acidosis.

Due to the rapidly increasing concentration of sodium in the cells, blood pressure drops and breathing becomes shallow. As a result, disorders of consciousness occur before heart and kidney failure finally occur. In less severe cases, the consequences include cramps, ataxia and breathing difficulties. Depending on the patient’s constitution, the individual symptoms can cause further complications. Intensive care treatment is always required for refeeding syndrome.

This is also associated with risks. The active ingredient adrenaline used in heart failure can cause serious gastrointestinal problems and permanently damage the kidneys and liver. In individual cases, the heart is also attacked and heart failure develops. Finally, allergic reactions to the agents and materials used cannot be ruled out.

When should you go to the doctor?

Refeeding syndrome must always be treated by a doctor. This condition is a serious condition that needs immediate treatment. In the worst case, if left untreated, the victim can die. Early treatment can prevent further symptoms or complications.

A doctor should be consulted if the patient suffers from severe confusion and a markedly reduced heart rate. The patients are often tired and cannot actively participate in everyday life. Breathing or heart failure may occur. If these symptoms persist, a doctor must be consulted. If the patient loses consciousness or stops breathing, an ambulance or hospital should be called immediately. Tremors or cramps in the muscles can also indicate refeeding syndrome. At the first signs of the syndrome, a general practitioner can be consulted. Symptoms can usually be completely relieved if early treatment is initiated.

Treatment & Therapy

To avoid refeeding syndrome, refeeding should always be performed under medical supervision. Before starting refeeding, deficient electrolytes and vitamins must first be substituted. This can be done orally, enterally or parenterally. High doses of vitamins and electrolytes should also be given for at least 10 days during refeeding.

Vitamin B1 should be administered thirty minutes before resuming nutrition, and then 200 to 300 mg orally or intravenously for at least three more days. Calorie intake depends on weight and starts at 15-20 kcal/kg/day. It will be gradually increased.


The measures described during refeeding can be used to prevent refeeding syndrome. It is important that the resumption of nutrition is carried out only under the supervision of a competent medical staff. After the mineral and vitamin status has been checked, any deficits must be compensated for before the start of refeeding. Even during refeeding, all values ​​require constant monitoring.


The follow-up treatment of refeeding syndrome depends on the underlying disease and the symptoms in which the refeeding syndrome has manifested itself. In patients with anorexia in particular, it is important to avoid renewed malnutrition, which is actually the underlying cause of the refeeding syndrome, because renewed malnutrition can lead to the recurrence of a refeeding syndrome. For this purpose, a balanced diet containing fat, protein and carbohydrates with a high calorie intake should be aimed at.

If malnutrition recurs, it is important to increase calorie intake slowly over the first ten days of treatment to prevent refeeding syndrome. In addition to this, all nutrient values ​​in the blood should also be checked regularly after a refeeding syndrome, since people who have had a refeeding syndrome once have an increased risk of malnutrition in the meantime and of the refeeding syndrome developing again.

If a deficiency is detected, nutritional supplements with the appropriate nutrients should be administered as a precautionary measure, even to patients of normal weight. If there is uncertainty as to whether these are being taken, they may need to be administered via infusions. If the refeeding syndrome has led to edema (water retention), treatment with water tablets (furosemide) and, if necessary, surgical removal of the water retention may be necessary. If constipation is present, administration of laxatives may be necessary to loosen the stool.

You can do that yourself

This condition usually affects people who, for a variety of reasons, have been malnourished or malnourished for a period of time and then try to eat normally again. The syndrome can be fatal if not recognized in time and treated in intensive care. In most cases, the patient only has a window of a few days.

The patient should be aware that prolonged starvation has cost the body minerals and vitamins it needs to process and digest the food it is now eating. Because they are missing, the various symptoms of refeeding syndrome occur, such as edema, discomfort and/or pain. At this point at the latest, the patient must visit a doctor or a clinic where their mineral and electrolyte balance can be closely monitored. Otherwise there is a risk of kidney and heart failure.

Generally, refeeding syndrome affects people who are force-fed parenterally for a known anorexia. But people who only force themselves to break their fast after weeks of voluntary fasting can also be affected, as can people who have been malnourished for a long time due to war or natural disasters and now have unrestricted access to food again.

Once the danger of suffering a refeeding syndrome has been averted, a diet rich in minerals and vitamins is recommended in order to replenish the body’s depleted stores over the long term.

Refeeding Syndrome