This kind of high nutritional value, delicate taste, a small piece of high-end ingredients - silver cod, by many mother and baby numbers and merchants as very suitable for making baby food, I believe that when the mother is not strangers, poor money is not bad money are eager to try, want to buy to their own babies to taste, and even some people often buy back.
Each e-commerce platform search for "silver cod", the product name will have the words "baby food", but this fish is not actually cod, and it has nothing to do with cod. Silver cod is a trade name, not a scientific name for fish.
There are two types of fish with the trade name "silver cod":
Bare-lid fish, English name Sablefish, trade name: silver cod, black cod, blue cod and so on. It is mainly distributed in bering, Alaska and other seas around the Arctic, with a lifespan of nearly 100 years.
Small-scaled canine toothfish, English name Patagonian toothfish/Bass Chilean, trade name: silver cod, Antarctic cod, canine toothfish, Chilean sea bass, French silver cod and so on. It is mainly distributed in Antarctic waters and has a lifespan of about 50 years.
Note: The domestic cod market is chaotic, and the cod sold through regular channels is marked with all the above deepening font words, or directly look at the English name, which is the real silver cod.
Domestic merchants and mother and baby numbers are sparing no effort to recommend silver cod, because there are almost no fine spines, tender flesh, a faint milk fragrance, and rich in DHA and EPA necessary for brain development.
But I may be ruining everyone's three views today.
We give the baby to eat deep-sea fish, nothing more than the Ω-3 fatty acids contained in fish oil, the brain and optic nerve development necessary substances. But when we choose deep-sea fish, don't forget that the harmful heavy metal in the fish body - mercury - commonly known as mercury - is highly toxic!
The U.S. Food and Drug Administration (FDA) and the U.S. Environmental Protection Agency (EPA) stress that fish with relatively high methylmercury levels should be cautious.
This is mercury in the free state, which is mercury, which is highly toxic
Mercury is naturally widespread in all rivers, lakes and seas, where it is converted to methylmercury under microbial action, and then reaches high levels in fish by the enrichment of the food chain. In addition to aquatic products being the main source, other animal foods of cereals, vegetables and fruits may also contain methylmercury.
The absorption rate of methylmercury in the human body is as high as 95%, which mainly affects the human nervous system, especially the developing brain, and can seriously cause language and memory impairment. And methylmercury can cross the placental barrier to invade the fetus and newborn, so pregnant women should be especially careful.
Pregnant women really don't go to eat cod
If the mercury content of the hair is found to be greater than 50 μg/g, it indicates the possibility of mercury poisoning. Minamata disease in Japan in middle school biology textbooks is caused by the long-term consumption of fish with high methylmercury content by local residents.
According to an August 2019 ecological study in the British journal Nature, marine ecological changes may have an impact on the accumulation of methylmercury in fish that humans regularly consume, such as cod and tuna. Scientists at Harvard University in the United States analyzed the data of the Atlantic Ocean for 30 years, and due to the destruction of marine ecology, the methylmercury content in marine fish is rising year by year.
The US Food and Drug Administration FDA gave the average methylmercury content of silver cod naked cover fish at 0.361 ppm and the average value of canine tooth fish was 0.354 ppm. (ppm=mg/kg, 1000 micrograms (μg) = 1 milligram (mg))
Note: ND mercury concentrations were below the detected level of 0.01 ppm
The Hong Kong Food Safety Centre also published two reports in 2019, namely that the mercury content of canine tooth fish in the Falkland Islands exceeded the standard, and the mercury content of naked lid fish imported from the United States exceeded the standard.
The WHO and FAO propose that the maximum tolerable weekly intake of methylmercury in humans is 1.6 μg/(kg·bw). That is, the maximum tolerated methylmercury intake per week for a baby weighing 10 kg is 16 micrograms.
Assuming that the mercury-containing food he eats in a week is only silver cod, and the average 1 kg naked fish contains 361 micrograms of methyl mercury, then the intake of silver cod this week should not exceed 45 grams, but this hypothesis is basically untenable. Even for adults of 60 kilograms, the weekly intake of cod should not exceed 266 grams, provided that the same assumptions are made. Pregnant women should especially pay attention to eating less, and young children with low weight should eat less and eat less. Eat up to once or twice a month, not more than 50 grams at a time.
The following figure is the recommended amount of complementary food given by the merchant who sells silver cod, and the 1-year-old baby is recommended to eat 100g at a time and eat once every 3 days. We can calculate that a 1-year-old baby weighs about 10kg, 200g of silver cod for 1 week, then the methylmercury intake is 72.2 micrograms, and the methylmercury intake exceeds the standard by 4.5 times!
It is conceivable that the long-term eating of silver cod, the loss is not the wallet, but the nervous system of the baby. Merchants give such a recommendation to ensure that the fish sell more and faster.
Some babies have small mouths that are more picky, just love this mouth, how to do it?
Careful you have wood to have seen the FDA test the sample size, minimum and maximum values. For example, the toothfish, the minimum value < 0.01ppm, the maximum value is actually 2.18ppm. This means that if you are lucky enough to buy a very small amount of mercury in cod, it is no problem to eat it regularly; but unfortunately, if you buy a particularly high mercury content, eating a spoonful of mercury may exceed the standard, which is also too terrible.
Why is the methylmercury content of the same fish so different?
This mainly depends on the origin of the fish. The less human activity there is, the less pollution there is, and the lower the amount of heavy metals contained in the fish that live in it, and vice versa.
So if you have to buy silver cod, you can pick up the map and look at it, the farther away from the coastline where human life is, the better.
The following figure is a survey analysis of the US Seafood Watch website to give recommendations for the selection of canine toothfish:
Produced in South Africa - the waters around Prince Edward Island in Antarctica and the Southern Indian Ocean, it is a good choice.
It is produced in the waters near Chile in the southeastern Pacific Ocean and is avoided.
In fact, there is no certain food that must be eaten, except for the milk that the baby drinks, because the baby can only eat milk. In addition to silver cod, we have many other options to complement DHA and EPA.
Look at the US FDA's recommendation: fish can bring us a variety of nutrients, and the current mercury content of most fish is actually very safe.
Most fish are still relatively safe, and a few fish should not be eaten again.
Note: ND mercury concentrations below the detected level of 0.01 ppmN/A data are not available
Fish in the green part are good choices
The FDA and the Environmental Protection Agency also released a reference note:
7 species to avoid: mackerel, marlin, orange snapper, shark, sailfish, Gulf of Mexico squarehead and bigeye tuna.
Best options: salmon (salmon), shrimp, cod (not silver cod), tilapia, catfish, flounder, crab, clams, etc.
Fish at the bottom of the food chain are relatively safe: oysters, scallops, herring, squid, pomfret, etc.
Intake needs to be controlled: halibut, snapper, totoaba (yellow fish), mackerel, mackerel, grouper, silver cod, etc.
If you are still not at ease, it is recommended that when handling marine fish, you can remove the parts where methylmercury accumulates more: fish skin, back, side and abdominal fat, fish internal organs, etc.
Articles with references are reliable:
①https://www.nature.com/articles/s41586-019-1468-9
②https://www.fda.gov/food/metals/mercury-levels-commercial-fish-and-shellfish-1990-2012
③https://www.cfs.gov.hk/sc_chi/press/20190319_7382.html
④https://www.cfs.gov.hk/sc_chi/press/20191015_7651.html
⑤https://www.seafoodwatch.org/seafood-recommendations/groups/toothfish?q=toothfish&t=toothfish
⑥https://www.fda.gov/food/consumers/advice-about-eating-fish
I am a registered dietitian Xiao Muqi, focusing on nutrition for 8 years, writing popular science I am very serious. Useful health knowledge is updated daily.
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