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Fish - healthy or poisonous?
Fish contain important nutrients, vitamins and fats, and many who want to eat healthier foods are increasingly replacing red meat with fish dishes. Consuming it indiscriminately is neither sustainable nor healthy.
contents
- Protein and vitamin bomb
- Omage-3 fatty acids
- Vitamin D
- Iodine and fish consumption
- Poisons in fish
- mercury
- mercury poisoning
- How does mercury get into the sea??
- Mercury contaminated fish
- Diseases
- Endangered enjoyment
- Sustainable consumption
- Bioseal with fish
- Aquaculture - an alternative?
- "Support your local dealer"
- References:
First of all, species at the top of the food chain contain high concentrations of mercury and other poisons, such as sharks or swordfish, and secondly, over 85% of the world's stocks are overfished and many esteemed fish species are threatened with extinction.
Protein and vitamin bomb
Fish contains up to 20% protein, which is good for the metabolism, because the body immediately converts 30% of the protein calories. Protein helps against eating attacks because it keeps blood sugar low.
Protein is needed for muscles to form. In fish contained can also digest very well.
Is fish basically healthy? Healthy for the body, mind and environment? Image: Yulia Fussmann - fotolia Omage-3 fatty acids
Fish contains omega-3 fatty acids, polyunsaturated fats that strengthen the cardiovascular system, prevent infections and support brain function. The body can not produce these fatty acids itself, so we have to take them. The best source for this is the "meat of the sea".
Most of these fatty acids contain so-called fatty fish, among the common edible fish are especially salmon, mackerel and herring. The fish can be fresh, smoked or pickled, the unsaturated fatty acids are preserved.
Vitamin D
Vitamin D develops our body from sunlight. Young people depend on vitamin D - if they are missing, the bones do not grow.
People with bent bones often suffer from a lack of vitamin D. Brittle teeth and tooth loss are also a sign of vitamin D deficiency.
Schizophrenia and depression are thought to be associated with insufficient vitamin D levels in the brain, and inadequate kidneys prevent the body from producing vitamin D itself.
High levels of vitamin D are important for people with multiple sclerosis and to prevent cancer. Vitamin D also helps fight an outbreak of cancer. He inhibits the growth of the tumor, as studies have shown, at least in colon cancer, prostate cancer, breast cancer, lung cancer and skin cancer.
Vitamin D regulates the calcium and phosphate balance in the body. It organizes the calcium build up in the bones and helps to extract calcium from the food, in addition it shortens the calcium level in the blood. When it sinks, a preform of vitamin D forms calcitriol, which dissolves calcium from the bones, causing the level in the blood to rise.
A balanced calcium level is necessary for the nerve cells to transmit stimuli and the muscles function.
For people in northern countries with long dark winters like Norway, Northern Russia or Finland, fish are vital - without them, they would not have had vitamin D available in winter. Salmon and cod are staple foods here.
Other foods also contain vitamin D, but none can be found in fatty fish. Russian dishes with cod and porcini mushroom combinations unusual for Central Europeans offer vitamin D in abundance, as well as tuna-filled avocados.
Offal such as liver, eggs and dairy products, stone and shiitake mushrooms also contain vitamin D, as well as avocados.
In the developed world, lifestyle leads to a lack of sunlight and therefore of vitamin D. We spend most of our time indoors, on the train or in the car, and not outdoors.
Regular walks and food fish on the table can compensate for this lack. About 200 grams of high-fat fish per week are almost enough to meet the vitamin D needs of a healthy adult.
However, older people should eat a lot more salmon or matjes. Over 65, the self-production of vitamin D from sunlight works less and less, and two to three times a week fish can help here.
The absolute star among the vitamin D suppliers is the smoked eel. It contains about 90 micrograms of it per 100 milligrams, fresh eel "only" brings it up to 20. Unfortunately, European eel is threatened with extinction, and WWF and Greenpeace say: keep away.
Smoked sprats, kippers and matje herring with between 28 and 33 micrograms per 100 grams are still rich in vitamin D, as well as trout 22 and salmon 17 micrograms. Low-cut off are low-fat species such as the redfish with 2.30 micrograms. Since redfish are also threatened, we should not eat them anyway.
Iodine and fish consumption
The thyroid gland can not work without iodine, and in this thyroid gland again hormones are formed, without which the metabolism can not work. Pregnant women and mothers with infants need iodine in quantities.
Salt has long been mixed with iodine to prevent widespread iodine deficiency. But we can do better with sea fish.
The front-runner is haddock with 417 micrograms of iodine per 100 g of fish, the all-round supermarket fish salmon contained in fish burgers - or chopsticks, still brings it to 263 micrograms, plaice to 291 and cod to 120, tuna "only" to 50.
But even the consumption of most tuna species is not recommended: Their stocks shrank in two decades by more than 90%. For example, the bluefin tuna could in a few years share the fate of Dronte and Beutelwolf.
Selenium also supports the thyroid and is abundant in fish.
Poisons in fish
Despite omega-3 fatty acids, vitamin D, iodine and selenium, fish consumption is not without problems. Seas, rivers and lakes are contaminated with pollutants.
Animals take these substances through the food. The basic rule is that the further up in the food pyramid an animal stands, the higher the levels of toxins in its body. The most common toxins found in fish are polychlorinated biphenyls (PCBs) and mercury.
mercury
The amount of mercury is highest in the large predatory fish, which are also popular food fish: sharks, swordfish and marlin, tuna and bonito.
A study in Austria from 2007 to 2015 showed that trout, carp, char, sardine, sprat, herring, salmon and Alaskan salmon were only slightly affected.
Medium values, but also below the legal limits, included zander, cod, cod, mackerel, anchovies, plaice, gilthead sea bream, bream, halibut and seabass.
Too high mercury concentrations showed tuna, snapper and especially butterfish. The butterfish was 677 micrograms per kilo - with a tolerated value of 1000 micrograms for high-fat fish ...
Seven out of 1751 samples exceeded the limits.
mercury poisoning
Mercury poisoning occurs when mercury accumulates in the organism. This is exactly what happens with fish that are at the top of the food chain and with people who consume these fish abundantly.
Such excess of mercury can cause malformations of fetuses, reduce nerve growth, and disrupt brain function. The consequences are disorders in learning and "dementia".
Too much mercury diminishes the oxygen in the red blood cells, disturbs the heart rhythm and raises the blood pressure. The risk of having a heart attack increases, in addition to disorders of the immune system, which in turn promote allergies, asthma and the chronic fatigue syndrome.
In addition, the risk of autoimmune diseases increases and those affected are more susceptible to viruses, bacteria and fungi.
Respiratory problems also favor mercury poisoning. Intestinal problems and energy loss are among the leading symptoms. Too much mercury also damages the stomach and intestinal mucosa. In particular, mercury changes the bacteria in the intestinal fauna.
Mercury is considered to be the third most harmful substance according to the three criteria frequency, contact with humans and toxicity - after arsenic and lead.
How poisoning manifests itself depends on how much mercury we get into, what state it is in, whether we take it in with food or breathe it in. When it accumulates in the body, outbreaks of poisoning can alternate with symptom-free times.
Mercury breaks the blood-brain barrier, causing toxins to reach the brain. Free oxygen radicals are formed, nerve cells die off, the dopamine balance breaks down, and the brain no longer produces messenger substances to the necessary extent.
In addition, mercury damages the entire endocrine system, poisoning the kidneys and damaging the areas of the brain that organize the movements.
Mercury damages the pituitary gland, the thyroid gland and the thymus gland, it accumulates in the ovaries, testicles and prostate, leading to impotence and infertility. It lowers the number of sperm and triggers menstrual pain.
It harms the embryo in the womb and quickly spreads across the placenta to the fetus.
Mercury directly damages the DNA, blocking the RNA and thus preventing the genetic information from transferring to proteins.
Toxic mercury with far-reaching health consequences. Image: jarun011 - fotolia The damage that mercury causes in the blood affects the fetus. The blood no longer supplies it adequately with oxygen, amino acids, glucose, magnesium, zinc and vitamin 12.
How does mercury get into the sea??
In the industrial age, the mercury content in the sea surface increased by 300%, and this is also reflected in the fish that live in this polluted water.
University of Michigan scientists compared mercury levels of yellowfin tuna from Hawaiian waters in 1971, 1998, and 2008. It is canned, sushi-style, and steaks in the freezer.
Accordingly, the mercury levels of tuna fish have been increasing steadily since 1998, at around 3.8 per cent per annum. The study thus proved, in particular, that also fish of the open sea increased mercury concentrate.
Mercury is released into the atmosphere, inter alia, by burning coal. Even natural waters absorb the substance through the air.
As early as 1976, the Canadian Medical Association published a report that Canadian Inuit people often suffered from mercury poisoning, people who ate more than a pound of fish every day.
Mercury contaminated fish
Most studies agree on which fish species have the highest mercury levels - but only as a rough guideline, because there are large differences between species from population to population.
The highest levels of mercury include: Grouper, Marlin, Atlantic Saber, Torpedo, King Macaque, Great Sharks, Big Tuna, Swordfish and Marlin.
High values include: leopardfish, halibut, sea trout, bluefish and bluefin tuna.
Low values include carp, mahi mahi, herring, monkfish, perch, most skate, cod and pacific tuna.
The lowest are anchovy, redfish, saithe, catfish, flounder, sole, haddock, salmon, sturgeon (including caviar), sardines and lake trout.
Diseases
Fish suffer from many diseases that are dangerous to humans. Most pathogens die by heating, so that cooked, roasted or grilled fish pose a low risk. The situation is different with sushi, which is getting more and more into the stomach outside of Japan.
1) Salomon Ellen
Fish near the coast, which are also weakened by sewage, often show high concentrations of bacteria that cause salmonellosis.
2) parasites
Various parasites, especially roundworms, thrive in fish. In the human body they lead to cramps in the stomach and vomiting. These nematodes spread through living larvae in the fish body, which also nest in the intestine of humans.
When the fish is heated, the worms die.
Endangered enjoyment
The global populations of many food fish are collapsing. On the one hand, this is due to the fact that the PH value in seawater shifts due to emitted CO2 - the oceans acidify.
Plastic garbage contaminates the oceans. Turtles die because they hold and eat plastic bags for jellyfish; even on remote islands, the beaches are covered with plastic.
Food fish eat small parts of plastic with plankton, and we pick up this plastic when we eat the fish.
Overfishing brings diverse species to the verge of extinction. Factory ships with huge trawls destroy the entire ocean floor, they tear everything with them and leave an ecological fiasco - as if one were to tear out a forest with its roots and then search out the deer.
About 23 to 73 million sharks are killed each year, according to the organization Sharklife - and that is just for shark fin soup, which Chinese people value. The fishermen usually cut off the animals' fins alive and then throw the animals back into the sea.
Add to this the 100 million sharks that land as by-catch in the fishing nets, with them sea turtles, dolphins, whales and seals.
85% of fish stocks are overfished today, 40% of catch is bycatch, and in trawl nets this is up to 90%.
Aquacultures usually do not reduce the problem, but reinforce it, because the farmed fish are fed with fishmeal and fish oil.
Aquaculture operators often destroy sea lions, dolphins and other fish eaters.
Sustainable consumption
Those who want to eat fish without promoting the destruction of marine fauna should pay attention to sustainability.
Sustainable consumption pays attention to the following:
1) How threatened is the fish species, and the corresponding population?
2) How gentle are the fishing methods? Trawls are NO-GO. Special fishing rods that only target the target species are better suited.
3) Ecologically sound aquaculture can be an alternative. If aquacultures damage ecosystems, such as mangrove forests?
Bioseal with fish
Certified organic labels help with the decision in the supermarket. The Marine Stewardship Council (MSC), Bioland and Naturland for aquaculture and followfish pay attention to sustainability.
Greenpeace and the WWF offer free shopping guides, which come to somewhat different results. The criteria of Greenpeace are in fact more stringent than those of the WWF.
Greenpeace creates eleven negative criteria. If one of them is true, it means: Stay away. These include not only the size of the stock, but also catching in sensitive ecosystems, destructive fishing methods such as trawls and high bycatch. Therefore, Greenpeace only recommends trout, herring, carp, mackerel and walleye.
Minor threats are herring from the Northeast Atlantic, cod from the eastern Baltic, salmon from the American Pacific, mackerel from the North Atlantic, anchovy from the Biscay, salmon from the northeastern Arctic, tilapia from cultures in Honduras, Indonesia, USA and Europe, Bonito from the Maldives.
Still okay, but second choice are Alaska salmon from the Pacific, trout from Northern Europe, black halibut from Norway and the northeastern Arctic, herring from the Baltic Sea, cod from Iceland, Norway and the Baltic Sea, salmon from Iceland, Norway and Scotland, Anchovies from Spain and the West Atlantic, Mediterranean and Northeast Atlantic sardines, Haddock from the Arctic, Norway and the North Sea, Bonito from the Western Pacific and European Zander.
You should refrain from European eel, spiny dogfish (especially Schillerlocken), trout and salmon from Chile, orange roughy, all other sharks and rays, halibut from the North Atlantic Ocean, cod from the Atlantic Ocean, mackerel from the eastern Central Atlantic, blue marlin , Swordfish, redfish, plaice from the Northeast Atlantic, monkfish from the North Atlantic Ocean, plaice from the Mediterranean, red snapper, red tuna, bluefin tuna, victoria and zander from Eastern Europe.
Aquaculture - an alternative?
Aquacultures were celebrated as a "blue revolution". Not only can it produce fish in large quantities, also conservationists saw aqua farms positively, in order to limit the depletion in the oceans.
Aquaculture as an alternative? Image: radzonimo - fotolia However, much of this aquaculture is just as much an ecological catastrophe as palm oil plantations in ruined rainforests. The mangrove belt of South Asia was relatively spared from the devastation of other ecosystems such as savannah or dry forest before the "blue revolution" because the brackish water zone could not be used industrially.
With aquacultures for shrimp farming, this changed rapidly - more and more mangrove forests were turned into shrimp farms.
Aquaculture today already comprises one third of the fish consumed. Mainly carp, catfish, trout and tilapia perch are bred here, more and more often also tuna, sea bream and sea bass. Cod, sole and sturgeon are also expected to come from farms in the future.
Except for carp and catfish, it is predatory fish. They need fish as food, so one kilo of farmed salmon devours five kilos of forage.
In non-sustainable aquaculture, faeces and farmed fish contaminate the surrounding waters in lakes, rivers and oceans.
If the fishmeal for the fish feed comes from wild catches, then a fish from aquaculture consumes several times its weight in wild fish.
For example, the breeding operations for Pangasius catfish in Vietnam are horrifying: Up to 80 fish in one cubic meter of water ensure that the animals can not move. Because they are constantly injured, they are stuffed with up to 50 antibiotics, pesticides prevent algae growth.
Salmon farms in Chile are also contaminated with medicines: Marine Harvest's annual report from 2007 showed that for every tonne of salmon in Norwegian breeds, 0.02 grams of antibiotics were used, compared to 732 grams in Chile, or 36,000 times as much. In 2008 salmon farms in Chile consumed 325 tonnes of medicines, Norway only one ton. 40% of antibiotics are also banned in the US.
Ecologically harmless are aquacultures for herbivores that feed on organic waste. Carp in Europe, grass carp in Asia and various catfish. These even live in paddy fields and provide a kind of permaculture. Their feces are used as fertilizers for aquatic plants, which in turn eat the fish.
Organic companies use only fishmeal as the remains of the fishing industry. 60 fish farms in the Naturland chain only allow for fish weighing ten kilos per cubic meter of water.
Naturland produces carp, trout, salmon and catfish, all of which bear the seal of nature but are also more expensive than conventional ones.
"Support your local dealer"
If you like fish on the menu, you should ask yourself if it must necessarily be exotic animals that are caught under questionable conditions. Carps, trout or walleye from local fishponds are harmless.
Traditional fish farming areas such as the pond landscapes of the Lusatia or the Meißendorfer ponds near Winsen / Aller are today hotspots of endangered species such as the otter, the white-tailed eagle or the red-bellied toad.
The fish are part of the ecosystem, and fish farming ensures that this ecosystem remains. (Dr. Utz Anhalt)
References:
doi: 10.1002 / etc.2883)
http://eatsmarter.de/ernaehrung/gesund-ernaehren/muss-unbedingt-fisch-essen
https://www.greenpeace.de/themen/meere/fischerei
http://www.greenpeace.de/files/publications/studie-quecksilber-kalberlahjennrich-20150526.pdf
http://www.scinexx.de/wissen-aktuell-18522-2015-02-03.html
http://www.wwf.de/aktiv-werden/tipps-fuer-den-alltag/vernuenftig-einkaufen/einkaufsratgeber-fisch/
http://www.vggoe.de/fileadmin/user_upload/news/Rote_Liste__Suesswasserfische_230909.pdf
Marine Stewardship Council (MSC)
Greenpeace
World Conservation Union IUCN
http://www.quetzal-leipzig.de/lateinamerika/chile/chile-fisch-lachsfarmen-umwelt-folgen-privatisierung-des-meeres-19093.html