Butterfish - Delicious Food or Revenge of a Delicacy?

Objective: In 2003, BfR had for the first time warned against the consumption of "butterfish" (escolar) on its homepage because of case reports from Australia although no cases had become officially known in Germany up to that time. After the press release, health complaints caused by "butterfish" were reported by more and more persons so that differentiated accounts of cases could be published as part of the regular annual reporting of the BfR Centre for Documentation and Assessment of Poisoinings. Recently, the number of inquiries of "butterfish" from the general public has increased to such a degree that BfR will deal with the topic in more detail in the context of early risk identification.Methods: All inquiries on "butterfish" received since the beginning of compulsory notification in 1990 were retrospectively evaluated and recorded in the form of case reports.Results: Since 2004, BfR has registered 39 cases of health disorders after consumptionof "butterfish". In 38 cases, health disorders were rated as minor, and in one case, as moderate due toan underlying disease. Typical manifestations included nausea, colicky abdominal pain and diarrhoea withcharacteristic orange oily stools and headache. Four persons required inpatient treatment. Based on the uniformsymptomatic picture of the 38 cases evaluated, the causal relationship has been rated as "probable". Conclusion: In predisposed persons, consumption of "butterfish" or "butter mackerel" of the species, Lepidocybium flavobrunneum and Ruvettuspretiosus may result in mild gastrointestinal symptoms with orange oily stools and headache, irrespective of thequantity consumed. Therapy will depend on the symptoms and/or consist of a special diet. Symptoms are presumablycaused by the presence of not readily or not digestible wax esters accounting for 90% of the oil ofthese fish species. Since manifestations included headache, it has been assumed that other factors such ascertain fish proteins having allergenic activity, or biogenic amines are also involved which may form duringextended storage. Possibly, health impairments can be avoided by suitable preparation practices such as discardingthe oil leaking from the food. BfR will look into health complaints caused by "butterfish" in more detail.