The liver of mammals, fowl, and fish is commonly eaten as food by humans (see offal). Pork, lamb, veal, beef, chicken, goose, and codlivers are widely available from butchers and supermarkets while stingray and burbot livers are common in some European countries.
Animal livers are rich in iron, copper, B vitamins and preformed vitamin A. Daily consumption of liver can be harmful; for instance, vitamin A toxicity has been proven to cause medical issues to babies born of pregnant mothers who consumed too much vitamin A.[3] For the same reason, consuming the livers of some species like polar bears, dogs, or moose is unsafe. A single serving of beef liver exceeds the tolerable upper intake level of vitamin A.[4] 100 g cod liver contains 5 mg of vitamin A and 100 μg of vitamin D.[5] Liver contains large amounts of vitamin B12, and this was one of the factors that led to the discovery of the vitamin.[6]
In the Romance languages, the anatomical word for "liver" (Frenchfoie, Italianfegato, Spanishhígado, etc.) derives not from the Latin anatomical term, jecur, but from the culinary term ficatum, literally "stuffed with figs", referring to the livers of geese that had been fattened on figs (foie gras).[7]
Some fish livers are valued as food, especially the stingray liver. It is used to prepare delicacies, such as poached skate liver on toast in England,[8] as well as the beignets de foie de raie and foie de raie en croute in French cuisine.[9] Cod liver (usually tinned in its oil and served seasoned) is a popular spread for bread or toast in several European countries. In Russia, it is served with potatoes. Cod liver oil is commonly used as a dietary supplement. Liver of burbot is eaten in Finland: it is common for fish vendors and supermarket fish aisles to sell these fish with liver and roe sacks still attached. These parts are often eaten boiled or added to burbot soup. Burbot and its liver are a traditional winter food.[10]
The livers of polar bears, walruses, bearded seals, and huskies can contain very high levels of preformed vitamin A,[11] and their consumption has led to vitamin A poisoning (hypervitaminosis A) according to several anecdotal reports. It has been estimated that consumption of 500 grams of polar bear liver would result in a toxic dose for a human.[11] Russian sailor Alexander Konrad, who accompanied explorer Valerian Albanov in a tragic ordeal over the Arctic ice in 1912, wrote about the awful effects of consuming polar bear liver.[12] Also, in 1913, Antarctic explorers on the Far Eastern PartyDouglas Mawson and Xavier Mertz were believed to have been poisoned, the latter fatally, from eating husky liver, though this claim has been recently contested.[13]
Mercury content in some species can also be an issue. In 2012, the Government of Nunavut, Canada warned pregnant women to lower their intake of ringed seal liver due to elevated levels of mercury.[14]
The neurotoxin in the liver of the pufferfish (which is consumed in Japanese cuisine as fugu, tightly regulated by Japanese law) contains the highest concentration of the tetrodotoxin, which characterizes the species. Consequently, the liver has been illegal to serve since 1984.
Traditions
Pig liver is a traditional food of immigrant Okinawans in Hawaii. It used to be eaten on New Year's Eve.[15]
In Pakistan and North India, the liver is eaten traditionally as the first meat of the sacrificial animal during Eid al-Adha. Kaleji masala or kaleji salan is popular throughout the festival.[16]
^National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Food and Nutrition Board; Committee to Review the Dietary Reference Intakes for Sodium and Potassium (2019). "Chapter 4: Potassium: Dietary Reference Intakes for Adequacy". In Oria, Maria; Harrison, Meghan; Stallings, Virginia A. (eds.). Dietary Reference Intakes for Sodium and Potassium. The National Academies Collection: Reports funded by National Institutes of Health. Washington, DC: National Academies Press (US). pp. 120–121. doi:10.17226/25353. ISBN978-0-309-48834-1. PMID30844154. Retrieved 2024-12-05.