Fish as food

From Wikipedia, the free encyclopedia
  (Redirected from Fish (food))
Jump to: navigation, search
This article is about fish as food for humans. For sealife in general as food, see seafood. For fish fed to other fish, see commercial fish feed and aquarium fish feed.
Redbelly tilapia presented as food

Fish is consumed as a food by many species, including humans. It has been an important source of protein and other nutrients for humans throughout recorded history.

In culinary and fishery contexts, the term fish can also include shellfish, such as molluscs, crustaceans and echinoderms. English does not distinguish between fish as an animal and the food prepared from it, as it does with pig vs. pork or cow vs. beef.[1] Some other languages do, as in the Spanish peces versus pescado. The modern English word for fish comes from the Old English word fisc (plural: fiscas) which was pronounced as it is today. English also has the term seafood, which covers fish as well as other marine life used as food.


Over 32,000 species of fish have been described,[2] making them the most diverse group of vertebrates. In addition, there are many species of shellfish. However, only a small number of species are commonly eaten by humans.

Common species of fish and shellfish used for food [3]
Mild flavour Moderate flavour Full flavour
basa, flounder, hake, scup, smelt, rainbow trout, hardshell clam, blue crab, peekytoe crab, spanner crab, cuttlefish, eastern oyster, Pacific oyster anchovy, herring, lingcod, moi, orange roughy, Atlantic ocean perch, Lake Victoria perch, yellow perch, European oyster, sea urchin Atlantic mackerel


See also: Fish processing

Fish can be prepared in a variety of ways. It can be uncooked (raw) (cf. sashimi). It can be cured by marinating (cf. escabeche), pickling (cf. pickled herring), or smoking (cf. smoked salmon). Or it can be cooked by baking, frying (cf. fish and chips), grilling, poaching (cf. court-bouillon), or steaming. Many of the preservation techniques used in different cultures have since become unnecessary but are still performed for their resulting taste and texture when consumed.

Nutritional value[edit]

Comparison of high-value nutrients in fish types Whitefish
Alaska pollock[4]
Oily fish
Atlantic herring[5]
Energy (kcal) 111 203
Protein (g) 23 23
Fat (g) 1 12
Cholesterol (mg) 86 77
Vitamin B-12 (µg) 4 13
Phosphorus (mg) 267 303
Selenium (µg) 44 47
Omega-3 (mg) 509 2014

"Fish provides a good source of high quality protein and contains many vitamins and minerals. It may be classed as either whitefish, oily or shellfish. Whitefish, such as haddock and seer, contain very little fat (usually less than 1%) whereas oily fish, such as sardines, contain between 10-25%. The latter, as a result of its high fat content, contain a range of fat-soluble vitamins (A, D, E and K) and essential fatty acids, all of which are vital for the healthy functioning of the body."[6]

Health benefits[edit]

Research over the past few decades has shown that the nutrients and minerals in fish, and particularly the omega-3 fatty acids found in pelagic fishes, are heart-friendly and can make improvements in brain development and reproduction. This has highlighted the role for fish in the functionality of the human body.[7]

Health hazards[edit]

Fish is the most common food to obstruct the airway and cause choking. Choking on fish was responsible for about reported 4,500 accidents in the UK in 1998.[8]


A seafood allergy is a hypersensitivity to an allergen which can be present in fish, and particularly in shellfish. This can result in an overreaction of the immune system and lead to severe physical symptoms.[9] Most people who have a food allergy also have a seafood allergy.[10] Allergic reactions can result from ingesting seafood, or by breathing in vapours from preparing or cooking seafood.[11] The most severe seafood allergy reaction is anaphylaxis, an emergency requiring immediate attention. It is treated with epinephrine.[12]

Specially prepared dish of the poisonous blowfish fugu, Japan


Some species of fish, notably the puffer fugu used for sushi, and some kinds of shellfish, can result in serious poisoning if not prepared properly. These fish always contain these poisons as a defense against predators; it is not present due to environmental circumstances. Particularly, fugu has a lethal dose of tetrodotoxin in its internal organs and must be prepared by a licensed fugu chef who has passed the national examination in Japan. Ciguatera poisoning can occur from eating larger fish from warm tropical waters, such as sea bass, grouper, and red snapper.[13] Scombroid poisoning can result from eating large oily fish which have sat around for too long before being refrigerated or frozen. This includes scombroids such as tuna and mackerel, but can also include non-scombroids such as mahi-mahi and amberjack.[13] The poison is odourless and tasteless.[14]

Many fish eat algae and other organisms that contain biotoxins (defensive substances against predators). Biotoxins accumulated in fish/shellfish include brevetoxins, okadaic acid, saxitoxins, ciguatoxin and domoic acid. Except for ciguatoxine, high levels of these toxins are only found in shellfish. Both domoic acid and ciguatoxine can be deadly to humans; the others will only cause diarrhea, dizzyness and a (temporary) feeling of claustrophobia.[15][16]

Shellfish are filter feeders and, therefore, accumulate toxins produced by microscopic algae, such as dinoflagellates and diatoms, and cyanobacteria. There are four syndromes called shellfish poisoning which can result in humans, sea mammals, and birds from the ingestion of toxic shellfish. These are primarily associated with bivalve molluscs, such as mussels, clams, oysters and scallops.[17] Fish, like anchovies can also concentrate toxins such as domoic acid.[18] If suspected, medical attention should be sought.

fish and shellfish poisoning
poisoning type symptoms duration toxin antidote sources
fish Ciguatera Nausea, vomiting and diarrhea, usually followed by headaches, muscle aches, paresthesia, numbness, ataxia, vertigo, and hallucinations. weeks to years ciguatoxin and similar: maitotoxin, scaritoxin and palytoxin none known [14][19]
Skin flushing, throbbing headache, oral burning, abdominal cramps, nausea, diarrhea, palpitations, sense of unease, and, rarely, collapse or loss of vision. Symptoms occur usually within 10–30 minutes of ingesting spoiled fish. usually four to six hours histamine, possibly others Oral anti-histamines [19][20]
Haff disease Rhabdomyolysis, that is, a swelling and breakdown of skeletal muscle (with a risk of acute kidney failure) within 24 hours after consuming fish a toxic cause is suspected but has not been proven none known [21]
Vivid auditory and visual hallucinations similar in some aspects to LSD. can last for several days [22]
shellfish Amnesic Permanent short-term memory loss and brain damage fatal in severe cases domoic acid, which acts as a neurotoxin none known [19]
Diarrheal diarrhea and possibly nausea, vomiting and cramps. symptoms usually set in within half an hour and last about a day okadaic acid, which inhibits intestinal cellular de-phosphorylation. [23]
Neurotoxic Vomiting and nausea and a variety of neurological symptoms such as slurred speech. Not fatal though it may require hospitalization. Brevetoxins or brevetoxin analogs [24][25]
Paralytic Includes nausea, vomiting, diarrhea, abdominal pain, and tingling or burning sensations. Other symptoms also possible. occasionally fatal principal toxin saxitoxin [26]

The toxins responsible for most shellfish and fish poisonings, including ciguatera and scombroid poisoning, are heat-resistant to the point where conventional cooking methods do not eliminate them.[14]

Mercury and other toxic metals[edit]

Main article: Mercury in fish

Fish products have been shown to contain varying amounts of heavy or toxic metals. Toxicity is a function of solubility, and insoluble compounds often exhibit negligible toxicity. Organometallic forms such as dimethyl mercury and tetraethyl lead can be extremely toxic.

mercury/omega-3 levels[27]
omega-3 ↓ low mercury
< 0.04 ppm
medium mercury
0.04–0.40 ppm
high mercury
> 0.40 ppm
> 1.0%
Atlantic mackerel
Spanish mackerel
pollock hoki
king mackerel
< 0.4%
tuna canned light
orange roughy

According to the US Food and Drug Administration (FDA), the risk from mercury by eating fish and shellfish is not a health concern for most people.[34] However, certain seafood contains sufficient mercury to harm an unborn baby or young child's developing nervous system. The FDA makes three recommendations for child-bearing women and young children:

  2. Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury. Four of the most commonly eaten fish that are low in mercury are canned light tuna, salmon, pollock, and catfish. Another commonly eaten fish, albacore ("white tuna") has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of albacore tuna per week.

These recommendations are also advised when feeding fish and shellfish to young children, but in smaller portions.[34]


When the ocean conservation organization Oceana examined over 1,200 seafood samples of seafood sold in the U.S between 2010 and 2012, they found one-third were mislabelled. The highest rate of mislabelling occurred with snapper at 87 percent, followed by tuna at 57 percent.[35]

Persistent organic pollutants[edit]

If fish and shellfish inhabit polluted waters, they can accumulate other toxic chemicals, particularly fat-soluble pollutants containing chlorine or bromine, dioxins or PCBs.[36] Fish that is to be eaten should be caught in unpolluted water. Some organisations such as SeafoodWatch, RIKILT, Environmental Defense Fund, IMARES provide information on species that do not accumulate much toxins/metals.[37][38][39][40]


Differential symptoms of parasite infections by raw fish. All have gastrointestinal, but otherwise distinct, symptoms.[41][42][43][44]

Parasites in fish are a natural occurrence and common. Though not a health concern in thoroughly cooked fish, parasites are a concern when consumers eat raw or lightly preserved fish such as sashimi, sushi, ceviche, and gravlax. The popularity of such raw fish dishes makes it important for consumers to be aware of this risk. Raw fish should be frozen to an internal temperature of −20 °C (−4 °F) for at least 7 days to kill parasites. Home freezers may not be cold enough to kill parasites.[45][46]

Traditionally, fish that live all or part of their lives in fresh water were considered unsuitable for sashimi due to the possibility of parasites (see Sashimi article). Parasitic infections from freshwater fish are a serious problem in some parts of the world, particularly Southeast Asia[citation needed]. Fish that spend part of their life cycle in brackish or fresh water, like salmon, are a particular problem. A study in Seattle, Washington showed that 100% of wild salmon had roundworm larvae capable of infecting people. In the same study farm-raised salmon did not have any roundworm larvae.[47]

Parasite infection by raw fish is rare in the developed world (fewer than 40 cases per year in the U.S.[citation needed]), and involves mainly three kinds of parasites: Clonorchis sinensis (a trematode/fluke), Anisakis (a nematode/roundworm) and Diphyllobothrium (a cestode/tapeworm). Infection risk of anisakis is particularly higher in fishes which may live in a river such as salmon (sake) in Salmonidae or mackerel (saba). Such parasite infections can generally be avoided by boiling, burning, preserving in salt or vinegar, or freezing overnight. In Japan it is common to eat raw salmon and ikura, but these foods are frozen overnight prior to eating to prevent infections from parasites, particularly anisakis.

Fish, meat and vegetarians[edit]

Hawaiian food: Seared ahi and wasabi beurre blanc sauce
Nutritional content of fish compared to meat
110 grams (4 oz or .25 lb)
Source calories protein carbs fat
chicken breast 160 28 g 0 g 7 g
lamb 250 30 g 0 g 14 g
steak (beef top round) 210 36 g 0 g 7 g
steak (beef T-bone) 450 25 g 0 g 35 g

Meat is animal flesh that is used as food.[48] Most often, this means the skeletal muscle and associated fat, but it may also describe other edible organs and tissues.[48] The term meat is used by the meat packing industry in a more restrictive sense—the flesh of mammalian species (pigs, cattle, etc.) raised and prepared for human consumption, to the exclusion of fish and poultry.

Vegetarians do not eat fish, and consider that fish is meat, since it is the flesh of an animal. Vegans or strict vegetarians refrain from consuming any animal products, not only meat and fish but, in contrast to ovo-lacto vegetarians, eggs, dairy products and all other animal-derived substances.

However, pescetarians eat fish and other seafood, but not mammals and birds. The Merriam-Webster dictionary dates the origin of the term pescetarian to 1993 and defines it to mean: "one whose diet includes fish but no other meat."[49] Pescatarians may consume fish based solely upon the idea that the fish are not factory farmed as land animals are (i.e., their problem is with the capitalist-industrial production of meat, not with the consumption of animal foods themselves).[50] Some eat fish with the justification that fish have less sophisticated nervous systems than land-dwelling animals. Others may choose to consume only wild fish based upon the lack of confinement, while choosing to not consume fish that have been farmed.

A 1999 metastudy combined data from five studies from western countries. The metastudy reported mortality ratios, where lower numbers indicated fewer deaths, for pescetarians (fish eaters) to be 0.82, vegetarians to be 0.84, occasional meat eaters to be 0.84. Regular meat eaters and vegans shared the highest mortality ratio of 1.00. The study reported the numbers of deaths in each category, and expected error ranges for each ratio, and adjustments made to the data. However, the "lower mortality was due largely to the relatively low prevalence of smoking in these [vegetarian] cohorts".[51]

In religion[edit]

See also: Kosher fish

Religious rites and rituals regarding food also tend to classify the birds of the air and the fish of the sea separately from land-bound mammals.[52] Sea-bound mammals are often treated as fish under religious laws - as in Jewish dietary law, which forbids the eating of cetacean meat, such as whale, dolphin or porpoise, because they are not "fish with fins and scales"; nor, as mammals, do they chew their cud and have cloven hooves, as required by Leviticus 11:9-12. Jewish (kosher) practice treat fish differently from other animal foods. The distinction between fish and "meat" is codified by the Jewish dietary law of kashrut, regarding the mixing of milk and meat, which does not forbid the mixing of milk and fish. Modern Jewish legal practice (halakha) on kashrut classifies the flesh of both mammals and birds as "meat"; fish are considered to be parve, neither meat nor a dairy food. (The preceding portion refers only to the halakha of Ashkenazi Jews, Sephardic Jews do not mix fish with dairy)

Seasonal religious prohibitions against eating meat do not usually include fish. For example, non-fish meat was forbidden during Lent and on all Fridays of the year in pre-Vatican II Roman Catholicism, but fish was permitted (as were eggs). (See Fasting in Catholicism.) In Eastern Orthodoxy, fish is permitted on some fast days when other meat is forbidden, but stricter fast days also prohibit fish with spines, while permitting invertebrate seafood such as shrimp and oysters, considering them "fish without blood."[citation needed]

Some Buddhists and Hindus (Brahmins of West Bengal, Odisha and Saraswat Brahmins of the Konkan) abjure meat that is not fish. Muslim (halal) practice also treats fish differently from other animal foods, as it can be eaten.

Taboos on eating fish[edit]

Among the Somali people, most clans have a taboo against the consumption of fish, and do not intermarry with the few occupational clans that do eat it.[53][54]



Certain species of fish are also forbidden in Judaism such as the freshwater eel (Anguillidae) and all species of catfish. Although they live in water, they appear to have no fins or scales (except under a microscope) (see Leviticus 11:10-13[56]). Sunni Muslim laws are more flexible in this and catfish and shark are generally seen as halal as they are special types of fish. Eel is generally considered permissible in the four Sunni madh'hab, but the Ja'fari jurisprudence followed by most Shia Muslims forbids it.[57][58][59]



See also[edit]


  1. ^ cf. culinary names
  2. ^ FishBase: June 2012 update. Retrieved 18 June 2012.
  4. ^ United States Department of Agriculture (September 2011). "Nutrient data for 15067, Fish, pollock, walleye, cooked, dry heat". USDA National Nutrient Database for Standard Reference, Release 24. Retrieved 22 July 2012. 
  5. ^ United States Department of Agriculture (September 2011). "Nutrient data for 15040, Fish, herring, Atlantic, cooked, dry heat". USDA National Nutrient Database for Standard Reference, Release 24. Retrieved 22 July 2012. 
  6. ^ Fellows P and Hampton A (Eds.) (1992) Fish and fish products Chapter 11 in: Small-scale food processing - A guide for appropriate equipment Intermediate Technology Publications, FAO, Rome. ISBN 1 85339 108 5.
  7. ^ "Nutritional Aspects of Fish." Irish Sea Fisheries Board
  8. ^ "Accident Statistics : 1998 - Home and leisure accident report Summary of 1998 data p.16 Department of Trade and Industry (UK)" (PDF). Retrieved 2011-10-29. 
  9. ^ National Institutes of Health, NIAID Allergy Statistics 2005
  10. ^ "Allergy Facts and Figures," Asthma and Allergy Foundation of America
  11. ^ "Seafood* (Fish, Crustaceans and Shellfish) - One of the nine most common food allergens". Canadian Food Inspection Agency. 2009-06-12. Retrieved 2009-06-21. 
  13. ^ a b Poisoning - fish and shellfish US National Library of Medicine. Retrieved 21 July 2012.
  15. ^ EOS magazine, July–August 2010
  16. ^ Natuurlijke toxinen in voedingsmiddelen
  17. ^ Silver, Mary Wilcox (2006), "Protecting Ourselves from Shellfish Poisoning", American Scientist 94 (4): 316–325, doi:10.1511/2006.60.316 
  18. ^ Domoic Acid Poisoning Northwest Fisheries Science Center, NOAA. Retrieved 16 July 2012.
  20. ^ Guss DA (1998). "Scombroid fish poisoning: successful treatment with cimetidine". Undersea Hyperb Med 25 (2): 123–5. PMID 9670438. Retrieved 2008-08-12. 
  21. ^ Buchholz U, Mouzin E, Dickey R, Moolenaar R, Sass N, Mascola L (2000). "Haff disease: from the Baltic Sea to the U.S. shore". Emerging Infectious Diseases 6 (2): 192–5. doi:10.3201/eid0602.000215. PMC 2640861. PMID 10756156. 
  22. ^ de Haro, L.; Pommier, P. (2006). "Hallucinatory fish poisoning (ichthyoallyeinotoxism): two case reports from the Western Mediterranean and literature review.". Clinical Toxicology (Philadelphia) 44 (2): 185–8. doi:10.1080/15563650500514590. PMID 16615678. 
  23. ^ Dawson, JF; Holmes CF (Oct 1999). "Molecular mechanisms underlying inhibition of protein phosphatases by marine toxins.". Front Biosc 4 (1-3): D646–58. doi:10.2741/dawson. PMID 10502549. 
  24. ^ Watkins, S. M.; Reich, A.; Fleming, L. E.; Hammond, R. (2008). "Neurotoxic shellfish poisoning" (PDF). Marine Drugs 6 (3): 431–455. doi:10.3390/md20080021. PMC 2579735. PMID 19005578. 
  25. ^ Landsberg, J. H. (2002). "The Effects of Harmful Algal Blooms on Aquatic Organisms". Reviews in Fisheries Science 10 (2): 113–390. doi:10.1080/20026491051695. 
  27. ^ Smith, KL; Guentzel, JL (2010). "Mercury concentrations and omega-3 fatty acids in fish and shrimp: Preferential consumption for maximum health benefits". Marine Pollution Bulletin 60 (9): 1615–1618. doi:10.1016/j.marpolbul.2010.06.045. 
  28. ^ The mercury levels in the table, unless otherwise indicated, are taken from: Mercury Levels in Commercial Fish and Shellfish (1990-2010) U.S. Food and Drug Administration. Accessed 8 January 2012.
  29. ^ "Fish, Levels of Mercury and Omega-3 Fatty Acids". American Heart Association. Retrieved October 6, 2010. 
  30. ^ Kris-Etherton, Penny M.; William S. Harris; Lawrence J. Appel (2002). "Fish Consumption, Fish Oil, Omega-3 Fatty Acids, and Cardiovascular Disease". Circulation 106 (21): 2747–2757. doi:10.1161/01.CIR.0000038493.65177.94. PMID 12438303. 
  31. ^ a b Trophic levels and maximum ages are, unless otherwise indicated, taken from the relevant species pages on Rainer Froese and Daniel Pauly (Eds) (2012) FishBase January 2012 version. Where a group has more than one species, the average of the principal commercial species is used
  34. ^ a b "What You Need to Know About Mercury in Fish and Shellfish". 2009-09-17. Retrieved 2011-10-29. 
  35. ^ Warner K, Timme W, Lowell B and Hirshfield M (2013) Oceana Study Reveals Seafood Fraud Nationwide Oceana.
  36. ^ PCBs in Fish and Shellfish Retrieved 22 March 2010.
  37. ^ "RIKILT". RIKILT. Retrieved 2011-10-29. 
  38. ^ "EDF Health Alerts about fish". Retrieved 2011-10-29. 
  39. ^ "IMARES". IMARES. Retrieved 2011-10-29. 
  40. ^ "SeaFoodWatch". Retrieved 2011-10-29. 
  42. ^ For Anisakiasis: WrongDiagnosis: Symptoms of Anisakiasis Retrieved on April 14, 2009
  45. ^ "''Parasites in Marine Fishes'' University of California Food Science & Technology Department Sea Grant Extension Program". 1990-08-07. Retrieved 2011-10-29. 
  46. ^ Vaughn M. Sushi and Sashimi Safety
  47. ^ Deardorff, TL; ML Kent (1989-07-01). "Prevalence of larval Anisakis simplex in pen-reared and wild-caught salmon (Salmonidae) from Puget Sound, Washington" (ABSTRACT). Journal of Wildlife Diseases 25 (3): 416–419. doi:10.7589/0090-3558-25.3.416. PMID 2761015. Retrieved 2008-03-03. 
  48. ^ a b Lawrie, 1.
  49. ^ Merriam-Webster Online Dictionary. 2009. "pescatarian." [Online] Merriam Webster, Inc. Available at [Accessed 17 July 2009]
  50. ^
  51. ^ Timothy J Key, Gary E Fraser, Margaret Thorogood, Paul N Appleby, Valerie Beral, Gillian Reeves, Michael L Burr, Jenny Chang-Claude, Rainer Frentzel-Beyme, Jan W Kuzma, Jim Mann and Klim McPherson (September 1999). "Mortality in vegetarians and non-vegetarians: detailed findings from a collaborative analysis of 5 prospective studies". American Journal of Clinical Nutrition 70 (3): 516S–524S. doi:10.1079/phn19980006. PMID 10479225. Retrieved 30 October 2009. 
  56. ^ Leviticus 11:10-13
  58. ^ "Is Catfish Halal?". Retrieved 2007-02-16. 


External links[edit]