Can it be eaten? Research reveals that mercury content remains high in 50 years! 4 kinds of fish should be eaten less

Fresh fish is not only the favorite fish of many gourmets, but also one of the most popular seafood in the world. Although fish and other seafood are rich in nutrients that are important for human health, such as omega-3, iron and iodine, they also contain mercury, a naturally occurring toxic heavy metal element.

In particular, fish will accumulate high levels of methylmercury by preying on stained gems, such as smaller fish or shell animals. A recent study published in the Environmental Science & Technology Letters pointed out that the mercury content in fish has not seemed to have changed since 1971.

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Methylmercury is the most common form of mercury in seafood and is also the most potentially harmful and can affect people of any age or health. Mercury enters the ocean mainly through industrial sources, surface currents and gas sediments.

Microorganisms in seawater convert mercury to methylmercury, and plankton and other marine organisms consume methylmercury. Small fish will prey on these marine creatures and then be eaten by the large fish. When mercury passes through the food chain of "big fish eat small fish, small fish eat rice", its concentration will increase even more. This is why large fish like salted fish have higher mercury content.

According to the U.S. Food and Drug Administration (FDA), methylmercury in fish can have a negative impact on everyone, regardless of age or health. However, unborn babies, babies and children are particularly at risk of adverse health effects due to exposure to mercury, including memory and awareness issues, reduced IQ and delayed exercise skills.

What is the reason why the mercury content in fish remains unchanged?

New research shows that the mercury content in fish is the same as more than 50 years ago, which is contrary to the researchers' expectations that reducing the amount of mercury in marine vegetables such as mines can reduce.

The study collected historical and current data on total mercury content of nearly 3,000 ferric fish caught in the Pacific, Atlantic and Indian Oceans between 1971 and 2022. Through analysis, researchers found that mercury concentration in global fish remains stable from 1971 to 2022.

The research team has estimated that mercury concentration in fish may be caused by past mercury emissions from seawater depths upward to lighter levels, which may have been emitted several years or even decades ago, but has not yet reflected the impact of reduced emissions in the air.

Researchers pointed out that in order to achieve a decrease in mercury concentration in the middle and upper-level fish in the future, emissions are reduced and long-term continuous mercury monitoring of marine biomes is needed.

What harm does methylmercury in fish species have to humans?

Toxics doctor Yang Zonghai once visited and pointed out that if methylmercury is taken from the diet, it can be absorbed through the gastric tract of the kidneys and the absorption rate can be as high as more than 95%. Methylmercury has been proven to affect the development of the fetus' brain and cause problems such as mental decline. Currently, there are no antidotes that can be used.

In addition to pregnant women and young people avoiding eating large deep-sea fish, clinical poisons and professional medical doctor Yang Zhenchang has also been interviewed and generally adults should avoid eating large fish as much as possible. Based on the maximum value of 1ppm of methylmercury in fish meat, a 50-kilogram adult will avoid eating more than 65 grams in a week, otherwise there may be risks of methylmercury accumulation in the body.

In addition, pork fish and flag fish are also common ingredients for raw fish slices, but nutritionist Huang Cuihua once received an interview reminder that if adults eat 2 raw fish slices, they may exceed the recommended value of 65 grams per week, and the risk of methylmercury is derived. "The safest way is not to eat it, and instead eat other fish species."

Which fish should be eaten less?

Although the mercury content in fish has remained unchanged for more than 50 years, high levels are still present in some species. The FDA said that since fish provides important nutrients, it should be part of a healthy diet plan for all ages, including pregnant women.

The Food and Drug Administration of the Ministry of Health and Welfare has ordered a guide to fish collection for designated fish in 2017. It is recommended that women with aged, pregnant women and children under the age of 6 should avoid eating the following four fish as much as possible:

. Shark

. Flagfish

. Sausage

. If you want to eat oil fish, it is recommended that pregnant and nurturing women should eat no more than 2 servings per week, and 1 serving of rosy fish. It is recommended to avoid children under the age of 6, or not to eat more than 1 serving per month.

How much is a portion of fish meat?

A portion of fish meat is equal to 35 grams, which is the size and thickness of the adult 3 fingers.

If you want to avoid eating the above four large fish types, you can choose small fish, such as squid fish, squid fish, saury fish, squid fish, squid fish, etc., which have relatively low metal retention.

How to distinguish the size of fish species? As long as the stitching section of the fish is larger than that of the adult's palm, it is a large fish. For example, the common vegetation body is quite large. Even if the vegetation section is half cut, it is still much larger than the palm. However, the vegetation section of the vegetation is about the size of the adult palm, which belongs to the medium-sized fish.

In addition, the heavy metal accumulated by the fish inner organ is usually relatively high. It is recommended to remove the inner organ and then recycle it.

It is worth noting that although the heavy metal content in small fish is less than that in large fish, it is not completely gone, and people are unlikely to eat it because of choking. Therefore, the best way is to reduce the consumption rate of large fish or avoid it.. Small and medium-sized fish species also need to change fish species frequently, such as eating saury fish today, eating fish tomorrow, and eating sea breeze the day after tomorrow, so as to avoid long-term and high-frequency consumption of the same fish species, which will cause health burden.