The liver of mammals, fowl, and fish is commonly eaten as food by humans (see offal). Pork, lamb, veal, beef, chicken, goose, and cod livers are widely available from butchers and supermarkets while stingray and burbot livers are common in some European countries.
Nutritional value per 100 g (3.5 oz) | |||||||||||||||||||||||||||||||||
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Energy | 561 kJ (134 kcal) | ||||||||||||||||||||||||||||||||
2.5 g | |||||||||||||||||||||||||||||||||
3.7 g | |||||||||||||||||||||||||||||||||
21 g | |||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||
This nutritional data is from 1992 and refers to raw pork liver only. Liver nutrients vary among species. | |||||||||||||||||||||||||||||||||
†Percentages estimated using US recommendations for adults, [1] except for potassium, which is estimated based on expert recommendation from the National Academies. [2] |
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]
From Middle English liver, from Old English lifer, from Proto-Germanic *librō, from Proto-Indo-European *leyp- "to smear, smudge, stick", from Proto-Indo-European *ley- "to be slimy, be sticky, glide". Cognate with Saterland Frisian Lieuwer "liver", West Frisian lever "liver", Dutch lever "liver", German Leber "liver", Danish, Norwegian and Swedish language lever "liver" the last three from Old Norse lifr "liver".
In the Romance languages, the anatomical word for "liver" (French foie, Italian fegato, Spanish hígado, 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]
Liver can be baked, boiled, broiled, fried, stir-fried, or eaten raw (asbeh nayeh or sawda naye in Lebanese cuisine, liver sashimi). In many preparations, pieces of liver are combined with pieces of meat or kidneys, like in the various forms of Middle Eastern mixed grill (e.g. meurav Yerushalmi ). Spreads or pâtés made from liver have various names, including liver pâté, pâté de foie gras, chopped liver, liverwurst, liver spread, and Braunschweiger. Other liver sausages include mazzafegato or salsiccia matta. A traditional South African delicacy, namely skilpadjies, is made of minced lamb's liver wrapped in netvet (caul fat), and grilled over an open fire.
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 Party Douglas 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.
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]
Parsley, or garden parsley is a species of flowering plant in the family Apiaceae that is native to Greece, Morocco and the former Yugoslavia. It has been introduced and naturalized in Europe and elsewhere in the world with suitable climates, and is widely cultivated as an herb and a vegetable.
Vitamin A is a fat-soluble vitamin that is an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinyl esters, and several provitamin (precursor) carotenoids, most notably β-carotene (beta-carotene). Vitamin A has multiple functions: growth during embryo development, maintaining the immune system, and healthy vision. For aiding vision specifically, it combines with the protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light and color vision.
Retinol, also called vitamin A1, is a fat-soluble vitamin in the vitamin A family that is found in food and used as a dietary supplement. Retinol or other forms of vitamin A are needed for vision, cellular development, maintenance of skin and mucous membranes, immune function and reproductive development. Dietary sources include fish, dairy products, and meat. As a supplement it is used to treat and prevent vitamin A deficiency, especially that which results in xerophthalmia. It is taken by mouth or by injection into a muscle. As an ingredient in skin-care products, it is used to reduce wrinkles and other effects of skin aging.
A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures such as hair, scales, feathers, or exoskeletons. Some nutrients can be metabolically converted into smaller molecules in the process of releasing energy such as for carbohydrates, lipids, proteins and fermentation products leading to end-products of water and carbon dioxide. All organisms require water. Essential nutrients for animals are the energy sources, some of the amino acids that are combined to create proteins, a subset of fatty acids, vitamins and certain minerals. Plants require more diverse minerals absorbed through roots, plus carbon dioxide and oxygen absorbed through leaves. Fungi live on dead or living organic matter and meet nutrient needs from their host.
Vitamin deficiency is the condition of a long-term lack of a vitamin. When caused by not enough vitamin intake it is classified as a primary deficiency, whereas when due to an underlying disorder such as malabsorption it is called a secondary deficiency. An underlying disorder can have 2 main causes:
A dietary supplement is a manufactured product intended to supplement a person's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources, or that are synthetic. The classes of nutrient compounds in supplements include vitamins, minerals, fiber, fatty acids, and amino acids. Dietary supplements can also contain substances that have not been confirmed as being essential to life, and so are not nutrients per se, but are marketed as having a beneficial biological effect, such as plant pigments or polyphenols. Animals can also be a source of supplement ingredients, such as collagen from chickens or fish for example. These are also sold individually and in combination, and may be combined with nutrient ingredients. The European Commission has also established harmonized rules to help insure that food supplements are safe and appropriately labeled.
Spinach is a leafy green flowering plant native to central and Western Asia. It is of the order Caryophyllales, family Amaranthaceae, subfamily Chenopodioideae. Its leaves are a common edible vegetable consumed either fresh, or after storage using preservation techniques by canning, freezing, or dehydration. It may be eaten cooked or raw, and the taste differs considerably; the high oxalate content may be reduced by steaming.
Cod liver oil is a dietary supplement derived from liver of cod fish (Gadidae). As with most fish oils, it contains the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and also vitamin A and vitamin D. Historically, it was given to children because vitamin D had been shown to prevent rickets, a consequence of vitamin D deficiency.
In the context of nutrition, a mineral is a chemical element. Some "minerals" are essential for life, but most are not. Minerals are one of the four groups of essential nutrients; the others are vitamins, essential fatty acids, and essential amino acids. The five major minerals in the human body are calcium, phosphorus, potassium, sodium, and magnesium. The remaining minerals are called "trace elements". The generally accepted trace elements are iron, chlorine, cobalt, copper, zinc, manganese, molybdenum, iodine, selenium, and bromine; there is some evidence that there may be more.
Fenugreek is an annual plant in the family Fabaceae, with leaves consisting of three small obovate to oblong leaflets. It is cultivated worldwide as a semiarid crop. Its leaves and seeds are common ingredients in dishes from the Indian subcontinent, and have been used as a culinary ingredient since ancient times. Its use as a food ingredient in small quantities is safe.
Offal, also called variety meats, pluck or organ meats, is the internal organs of a butchered animal. The word does not refer to a particular list of edible organs, and these lists of organs vary with culture and region, but usually exclude skeletal muscle. Offal may also refer to the by-products of milled grains, such as corn or wheat.
Cress, sometimes referred to as garden cress to distinguish it from similar plants also referred to as cress, is a rather fast-growing, edible herb.
Hypervitaminosis A refers to the toxic effects of ingesting too much preformed vitamin A. Symptoms arise as a result of altered bone metabolism and altered metabolism of other fat-soluble vitamins. Hypervitaminosis A is believed to have occurred in early humans, and the problem has persisted throughout human history. Toxicity results from ingesting too much preformed vitamin A from foods, supplements, or prescription medications and can be prevented by ingesting no more than the recommended daily amount.
Chromium deficiency is described as the consequence of an insufficient dietary intake of the mineral chromium. Chromium was first proposed as an essential element for normal glucose metabolism in 1959, but its biological function has not been identified. Cases of deficiency were described in people who received all of their nutrition intravenously for long periods of time.
Glebionis coronaria, formerly called Chrysanthemum coronarium, is a species of flowering plant in the family Asteraceae. It is native to the Mediterranean region. It is cultivated and naturalized in East Asia and in scattered locations in North America.
Laverbread is a food product made from laver, an edible seaweed consumed mainly in Wales as part of local traditional cuisine. The seaweed is commonly found around the west coast of Great Britain, and the coasts of Ireland, where it is known as sleabhac. It is smooth in texture and forms delicate, sheetlike thalli, often clinging to rocks. The principal variety is Porphyra umbilicalis, a red algae which tends to be a brownish colour, but boils down to a dark green pulp when prepared. Laver seaweed has a high content of dietary minerals, particularly iodine and iron. The high iodine content gives the seaweed a distinctive flavour in common with olives and oysters.
Herring are forage fish in the wild, mostly belonging to the family Clupeidae. They are an important food for humans. Herring often move in large schools around fishing banks and near the coast. The most abundant and commercially important species belong to the genus Clupea, found particularly in shallow, temperate waters of the North Pacific and North Atlantic Oceans, including the Baltic Sea, as well as off the west coast of South America. Three species of Clupea are recognized; the main taxon, the Atlantic herring, accounts for over half the world's commercial capture of herrings.
Mackerel is an important food fish that is consumed worldwide. As an oily fish, it is a rich source of omega-3 fatty acids. The flesh of mackerel spoils quickly, especially in the tropics, and can cause scombroid food poisoning. Accordingly, it should be eaten on the day of capture, unless properly refrigerated or cured.
Cod and other cod-like fish have been widely used as food through history. Other cod-like fish come from the same family (Gadidae) that cod belong to, such as haddock, pollock, and whiting.
Seal meat is the flesh, including the blubber and organs, of seals used as food for humans or other animals. It is prepared in numerous ways, often being hung and dried before consumption. Historically, it has been eaten in many parts of the world.