Refeeding syndrome

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Refeeding syndrome
Starvation from one month in a Viet Cong prison camp in 1966.
SymptomsWeakness, decreased breathing, poor coordination, confusion, seizures, heart arrythmias[1]
Risk factorsEating disorders, alcoholism, post surgery, chronic malnutrition, bariatric surgery, inflammatory bowel disease[1]
Diagnostic methodBased on history and blood tests after ruling out other possible causes[1]
TreatmentGradual reintroduction of calories, vitamin and mineral supplements[1]

Refeeding syndrome is a condition that may occur following reintroduction of nutrition after a prolonged period of starvation.[1] It may also occur with nutrition in the form of total parenteral nutrition.[1] It may result in low phosphate, low magnesium, low potassium, and low thiamine.[1] This may result in weakness, decreased breathing, poor coordination, confusion, seizures, and heart arrythmias.[1]

Risk factors include eating disorders, alcoholism, following surgery, chronic malnutrition, bariatric surgery, and inflammatory bowel disease.[1] The underlying mechanism involves increased blood sugar leading to increased insulin levels which results in uptake of potassium and phosphate by cells.[1] Diagnosis is based on a decrease in blood levels of phosphate, potassium, or magnesium.[1] Mild disease is a decrease of 10 to 20%, moderate disease a decrease of 20 to 30%, and severe disease a decrease of greater than 30%.[1]

Treatment is by the gradual reintroduction of calories.[1] In the first 24 hours, 10 to 20 kcal/kg or no more than half the person energy requirement, is recommended.[2][1] Thiamine supplements should be given early.[1] Potassium, phosphate, calcium, and magnesium supplements are also often recommended.[2] Electrolytes should be measured every 12 hours initially.[1]

The frequency of refeeding syndrome is unclear.[1] One study found rates of 0.5% to 18% among people who had been hospitalized.[1] Modern descriptions of the condition date from World War II.[1] Though, a number of prior descriptions of people dying following eating after a famine occur throughout history.[3][4]

Signs and symptoms

Symptoms may include weakness, decreased breathing, poor coordination, confusion, seizures, and heart arrythmias.[1]


Any individual who has had a negligible nutrient intake for many consecutive days and/or is metabolically stressed from a critical illness or major surgery is at risk of refeeding syndrome. Refeeding syndrome usually occurs within four days of starting to re-feed. People can develop fluid and electrolyte imbalance, especially hypophosphatemia, along with neurologic, pulmonary, cardiac, neuromuscular, and hematologic complications.[citation needed]

During fasting, the body switches its main fuel source from carbohydrates to fat tissue fatty acids and amino acids as the main energy sources. The spleen decreases its rate of red blood cell breakdown thus conserving red blood cells. Many intracellular minerals become severely depleted during this period, although serum levels remain normal. Importantly, insulin secretion is suppressed in this fasting state, and glucagon secretion is increased.[2]

During refeeding, insulin secretion resumes in response to increased blood sugar, resulting in increased glycogen, fat and protein synthesis. Refeeding increases the basal metabolic rate. The process requires phosphates, magnesium and potassium which are already depleted, and the stores rapidly become used up. Formation of phosphorylated carbohydrate compounds in the liver and skeletal muscle depletes intracellular ATP and 2,3-diphosphoglycerate in red blood cells, leading to cellular dysfunction and inadequate oxygen delivery to the body's organs. Intracellular movement of electrolytes occurs along with a fall in the serum electrolytes, including phosphorus and magnesium. Levels of serum glucose may rise, and B1 vitamin thiamine may fall. Abnormal heart rhythms are the most common cause of death from refeeding syndrome, with other significant risks including confusion, coma and convulsions and heart failure.[citation needed]


The syndrome can occur at the beginning of treatment for anorexia nervosa when patients have an increase in calorie intake and can be fatal.[5] It can also occur after the onset of a severe illness or major surgery. The shifting of electrolytes and fluid balance increases cardiac workload and heart rate. This can lead to acute heart failure. Oxygen consumption is increased which strains the respiratory system and can make weaning from ventilation more difficult.[citation needed]


Refeeding syndrome can be fatal if not recognized and treated properly. An awareness of the condition and a high index of suspicion are required in order to make the diagnosis. The electrolyte disturbances of the refeeding syndrome can occur within the first few days of refeeding. Close monitoring of blood biochemistry is therefore necessary in the early refeeding period.


In critically ill patients admitted to an intensive care unit, if phosphate drops to below 0.65 mmol/L (2.0 mg/dL) from a previously normal level within three days of starting enteral or parenteral nutrition, caloric intake should be reduced to 480 kcals per day for at least two days whilst electrolytes are replaced.[6] Daily doses of thiamine, vitamin B complex (strong) and a multivitamin and mineral preparation are strongly recommended. Blood biochemistry should be monitored regularly until it is stable. Although clinical trials are lacking in patients other than those admitted to an intensive care, it is commonly recommended that energy intake should remain lower than that normally required for the first 3–5 days of treatment of refeeding syndrome for all patients.[7]


In his 5th century BC work 'On Fleshes' (De Carnibus), Hippocrates writes, "if a person goes seven days without eating or drinking anything, in this period most die; but there are some who survive that time but still die, and others are persuaded not to starve themselves to death but to eat and drink: however, the cavity no longer admits anything because the jejunum (nêstis) has grown together in that many days, and these people too die." Though Hippocrates misidentifies the exact cause of death, this passage likely represents an early description of refeeding syndrome.[8] The Roman Historian Flavius Josephus writing in the first century described classic symptoms of the syndrome among survivors of the siege of Jerusalem. He described the death of those who overindulged in food after famine, whereas those who ate at a more restrained pace survived.[9]

There are anecdotal eyewitness reports from Polish prisoners in Iran who were freed from Soviet camps in 1941–1942 under an amnesty to form an army under General Anders and were given food whilst in a state of starvation, which caused many to die.[10]

A common error, repeated in multiple papers, is that "The syndrome was first described after World War II in Americans who, held by the Japanese as prisoners of war, had become malnourished during captivity and who were then released to the care of United States personnel in the Philippines."[11] However, closer inspection of the 1951 paper by Schnitker reveals the prisoners under study were not American POWs but Japanese soldiers who, already malnourished, surrendered in the Philippines during 1945, after the war was over.

It is difficult to ascertain when the syndrome was first discovered and named, but it is likely the associated electrolyte disturbances were identified perhaps in Holland, the Netherlands during the closing months of World War II, before Victory in Europe Day.[12]

See also


  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 Persaud-Sharma, D; Saha, S; Trippensee, AW (January 2021). "Refeeding Syndrome". PMID 33232094. {{cite journal}}: Cite journal requires |journal= (help)
  2. 2.0 2.1 2.2 Mehanna HM, Moledina J, Travis J (June 2008). "Refeeding syndrome: what it is, and how to prevent and treat it". BMJ. 336 (7659): 1495–8. doi:10.1136/bmj.a301. PMC 2440847. PMID 18583681. Archived from the original on 2021-08-29. Retrieved 2009-02-24.
  3. "Refeeding Syndrome in Historical Perspective: Its First Description by Rodulfus Glaber (1033)" (PDF). AJBSR. January 7 2021. doi:10.34297/AJBSR.2021.11.001644. Archived (PDF) from the original on 16 January 2021. Retrieved 7 March 2021. {{cite journal}}: Check date values in: |date= (help)
  4. De Santo, Natale G; Bisaccia, Carmela; Phillips, Malcolm E; De Santo, Luca S (11 December 2020). "Refeeding syndrome as described in 1507 by Antonio Benivieni in Florence". Nephrology Dialysis Transplantation. doi:10.1093/ndt/gfaa295. PMID 33313827.
  5. Webb GJ, Smith K, Thursby-Pelham F, Smith T, Stroud MA, Da Silva AN (2011). "Complications of emergency refeeding in anorexia nervosa: case series and review". Acute Medicine. 10 (2): 69–76. PMID 22041604.
  6. Doig, GS; Simpson, F; Heighes; Bellomo, R; Chesher, D; Caterson, ID; Reade, MC; Harrigan, PWJ (2015-12-01). "Restricted versus continued standard caloric intake during the management of refeeding syndrome in critically ill adults: a randomised, parallel-group, multicentre, single-blind controlled trial". The Lancet Respiratory Medicine. 3 (12): 943–952. doi:10.1016/S2213-2600(15)00418-X. ISSN 2213-2619. PMID 26597128.
  7. "Nutrition support in adults: oral nutrition support, enteral tube feeding and parenteral nutrition. Full guideline [NICE. Clinical guideline CG32]". National Institute for Clinical Excellence. 2006–2014. Archived from the original on February 9, 2019. Retrieved April 26, 2017.
  8. Hippocrates of Kos. De Carnibus. 5th century BCE.
  9. The Wars of the Jews by Flavius Josephus. October 2001. p. book V, chapter XIII, paragraph 4. Archived from the original on 2019-01-29. Retrieved 2018-05-22.
  10. Many of these deaths were due to dysentery, typhoid and other diseases but this was largely amongst the civilian evacuees from Poland. Clear eyewitness reports identify eating too much as a cause.
  11. Schnitker MA, Mattman PE, Bliss TL (1951). "A clinical study of malnutrition in Japanese prisoners of war". Annals of Internal Medicine. 35 (1): 69–96. doi:10.7326/0003-4819-35-1-69. PMID 14847450.
  12. Burger, GCE; BSandstead, HR; Drummond, J (1945). "Starvation in Western Holland:1945". Lancet. 246 (6366): 282–83. doi:10.1016/s0140-6736(45)90738-0.

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