What is "fish oil"

Fish \Fish\, n.; pl. Fishes (f[i^]sh"[e^]z), or collectively, Fish. [OE. fisch, fisc, fis, AS. fisc; akin to D. visch, OS. & OHG. fisk, G. fisch, Icel. fiskr, Sw. & Dan. fisk, Goth. fisks, L. piscis, Ir. iasg. Cf. Piscatorial. In some cases, such as fish joint, fish plate, this word has prob. been confused with fish, fr. F. fichea peg.]

1. A name loosely applied in popular usage to many animals of diverse characteristics, living in the water.

2. (Zo["o]l.) An oviparous, vertebrate animal usually having fins and a covering scales or plates. It breathes by means of gills, and lives almost entirely in the water. See Pisces.

   Note: The true fishes include the Teleostei (bony fishes), Ganoidei, Dipnoi, and Elasmobranchii or Selachians (sharks and skates). Formerly the leptocardia and Marsipobranciata were also included, but these are now generally regarded as two distinct classes, below the fishes.

3. pl. The twelfth sign of the zodiac; Pisces.

4. The flesh of fish, used as food.

5. (Naut.)

   1. A purchase used to fish the anchor.

   2. A piece of timber, somewhat in the form of a fish, used to strengthen a mast or yard. Note: Fish is used adjectively or as part of a compound word; as, fish line, fish pole, fish spear, fish-bellied. Age of Fishes. See under Age, n., 8. Fish ball, fish (usually salted codfish) shared fine, mixed with mashed potato, and made into the form of a small, round cake. [U.S.] Fish bar. Same as Fish plate (below). Fish beam (Mech.), a beam one of whose sides (commonly the under one) swells out like the belly of a fish. --Francis. Fish crow (Zo["o]l.), a species of crow ( Corvus ossifragus), found on the Atlantic coast of the United States. It feeds largely on fish. Fish culture, the artifical breeding and rearing of fish; pisciculture. Fish davit. See Davit. Fish day, a day on which fish is eaten; a fast day. Fish duck (Zo["o]l.), any species of merganser. Fish fall, the tackle depending from the fish davit, used in hauling up the anchor to the gunwale of a ship. Fish garth, a dam or weir in a river for keeping fish or taking them easily. Fish glue. See Isinglass. Fish joint, a joint formed by a plate or pair of plates fastened upon two meeting beams, plates, etc., at their junction; -- used largely in connecting the rails of railroads. Fish kettle, a long kettle for boiling fish whole. Fish ladder, a dam with a series of steps which fish can leap in order to ascend falls in a river. Fish line, or Fishing line, a line made of twisted hair, silk, etc., used in angling. Fish louse (Zo["o]l.), any crustacean parasitic on fishes, esp. the parasitic Copepoda, belonging to Caligus, Argulus, and other related genera. See Branchiura. Fish maw (Zo["o]l.), the stomach of a fish; also, the air bladder, or sound. Fish meal, fish desiccated and ground fine, for use in soups, etc. Fish oil, oil obtained from the bodies of fish and marine animals, as whales, seals, sharks, from cods' livers, etc. Fish owl (Zo["o]l.), a fish-eating owl of the Old World genera Scotopelia and Ketupa, esp. a large East Indian species ( K. Ceylonensis). Fish plate, one of the plates of a fish joint. Fish pot, a wicker basket, sunk, with a float attached, for catching crabs, lobsters, etc. Fish pound, a net attached to stakes, for entrapping and catching fish; a weir. [Local, U.S.] --Bartlett. Fish slice, a broad knife for dividing fish at table; a fish trowel. Fish slide, an inclined box set in a stream at a small fall, or ripple, to catch fish descending the current. --Knight. Fish sound, the air bladder of certain fishes, esp. those that are dried and used as food, or in the arts, as for the preparation of isinglass. Fish story, a story which taxes credulity; an extravagant or incredible narration. [Colloq. U.S.] --Bartlett. Fish strainer.

      1. A metal colander, with handles, for taking fish from a boiler.

      2. A perforated earthenware slab at the bottom of a dish, to drain the water from a boiled fish.

         Fish trowel, a fish slice.

         Fish weir or Fish wear, a weir set in a stream, for catching fish.

         Neither fish nor flesh, Neither fish nor fowl (Fig.), neither one thing nor the other.

n. oil obtained from fish

Fish oil is oil derived from the tissues of oily fish. Fish oils contain the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), precursors of certain eicosanoids that are known to reduce inflammation in the body, and have other health benefits. Nonetheless, fish oil supplement studies have failed to support claims of preventing heart attacks or strokes.

The fish used as sources do not actually produce omega-3 fatty acids, but instead accumulate them by consuming either microalgae or prey fish that have accumulated omega-3 fatty acids.

Fatty predatory fish like sharks, swordfish, tilefish, and albacore tuna may be high in omega-3 fatty acids, but due to their position at the top of the food chain, these species may also accumulate toxic substances through biomagnification. For this reason, the United States Environmental Protection Agency recommends limiting consumption (especially for women of childbearing age) of certain (predatory) fish species (e.g. albacore tuna, shark, king mackerel, tilefish and swordfish) due to high levels of the toxic contaminant mercury. Dioxin, PCBs and chlordane are also present. Fish oil is used as a component in aquaculture feed. More than 50 percent of the world's fish oil used in aquaculture feed is fed to farmed salmon.

Marine and freshwater fish oil vary in contents of arachidonic acid, EPA and DHA. The various species range from lean to fatty and their oil content in the tissues has been shown to vary from 0.7% to 15.5%. They also differ in their effects on organ lipids. Studies have revealed that there is no relation between total fish intake or estimated omega−3 fatty acid intake from all fish, and serum omega−3 fatty acid concentrations. Only fatty fish intake, particularly salmonid, and estimated EPA + DHA intake from fatty fish has been observed to be significantly associated with increase in serum EPA + DHA.

The omega-3 fatty acids in fish oil are thought to be beneficial in treating hypertriglyceridemia, although claims of preventing heart attacks or strokes have not been supported. Fish oil and omega-3 fatty acids have been studied in a wide variety of other conditions, such as clinical depression, anxiety, cancer, and macular degeneration, yet benefits in these conditions have not been verified.