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Hello, everyone.

I am Yoko Maeda, a certified aesthetic medicine specialist at BIANCA.

 

 

By the way, do you like tuna or sea bream?

It's very delicious and I like it too, but for your health, you might want to be careful not to eat too much.

 

The reason lies in the methylmercury found in seafood. Eating large amounts of tuna or sea bream could lead to significant methylmercury accumulation in your body without you even realizing it! This time, I'd like to discuss the amount of mercury contained in seafood.

 

 

 

Fish is a food rich in high-quality protein and fatty acids, but it also contains harmful substances like methylmercury, which cannot be removed by cooking.

 

Methylmercury absorbed into the body is gradually excreted over time, so not all ingested amounts accumulate. However, caution is advised against excessive intake during pregnancy. This is because the baby in the womb is sensitive to chemicals, and ingesting a certain amount of methylmercury may affect fetal development.

 

Source:Ministry of Health, Labour and Welfare

 

This diagram from the Ministry of Health, Labour and Welfare shows fish that pregnant women should avoid eating in excess. It reveals that fish high in mercury content—such as tuna, swordfish, and sea bream—are those at the top of the food chain.

 

This is because methylmercury readily dissolves in fat and tends to accumulate, leading to increased concentrations through the food chain. As smaller fish are eaten by larger fish in repeated cycles of the food chain, mercury concentrations gradually rise, making it highly likely that methylmercury accumulates in fatty tissues.

 

Methylmercury consumed through food comes mostly from seafood. Because Japanese people habitually eat fish, it's said that methylmercury accumulates in their bodies at about ten times the level found in Americans.

 

What are the symptoms caused by methylmercury?

 

 

"What happens if you consume a lot of methylmercury?" Many people probably wonder about this. Consuming high levels of methylmercury can potentially cause the following symptoms:

 

 

Among the adverse effects of high methylmercury intake, diabetes is likely the most relevant to Japanese people. While it's said that Japanese people have a predisposition to diabetes, methylmercury consumption may also be a contributing factor. It's not uncommon for diabetes metrics to improve after detoxifying methylmercury.

Other symptoms reported by individuals include muscle pain, headaches, and hair loss. If you're concerned about how much mercury has accumulated in your body, there are methods available to test your methylmercury levels, so getting tested is one option.

 

 

What kind of fish should I eat?

 

 

Fish at the top of the food chain are certainly safe to eat, but caution is needed regarding excessive consumption. The Ministry of Health, Labour and Welfare recommends eating them no more than twice a week, limiting intake to approximately 100–200 grams per week.

 

However, fish containing animal protein are one of the foods we should actively consume from an anti-aging perspective. So, what kinds of fish should we actively eat? Fish lower down the food chain with low methylmercury levels. Fish that are more likely to be eaten than to eat others, in other words. Examples include salmon, yellowfin tuna, mackerel, Pacific saury, sardines, horse mackerel, and bonito—the so-called bluefish.

 

Bluefish contain low levels of methylmercury and are rich in omega-3 fatty acids, a high-quality type of fat found in fish oil. Eating bluefish regularly is better for your health.

 

In addition to external care, paying attention to your daily diet is also an essential element of anti-aging care. If you wish to approach anti-aging care from an internal medicine perspective, please feel free to consult with us.