Mr. Liu (China) enjoys eating sashimi and usually eats it two to three times a week. According to him, “it has a more original flavor and is healthier.”

Last weekend, he traveled to Shunde. His friend ordered a huge bowl of sashimi just for him, which delighted him greatly. Unexpectedly, that very night, he suddenly developed a cough and a high fever. An emergency examination at the hospital revealed that his left liver was riddled with holes. Further tests led to a diagnosis of Clonorchis sinensis infection.

After reviewing his medical history, doctors concluded that the condition was related to the bowl of sashimi he had eaten. Mr. Liu was subsequently treated in the hospital. After recovering and being discharged, he vowed never to eat sashimi again.

A Man’s Liver Riddled Like a Honeycomb Due to Frequently Eating One Type of Fish: Doctors Advise Eating These 4 Types of Fish as Little as Possible Because They Contain Carcinogens – Image 1

Four Types of Fish Doctors Recommend Eating as Little as Possible Due to Carcinogenic Risks

In 2022, a large-scale study published by the Department of Public Health and Cancer Control at Brown University placed fish consumption under scrutiny for its potential link to cancer.

The study analyzed fish consumption data from more than 491,000 Americans with an average age of 62 and examined its association with the risk of developing malignant melanoma and melanoma in situ. The results showed a significant positive correlation between the two factors. Specifically, higher consumption of non-fried fish and tuna significantly increased the risk of malignant melanoma and stage 0 melanoma, while fried fish showed no significant correlation with either condition.

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However, the researchers also cautioned that this was only an observational study and could not establish a causal relationship. A preliminary hypothesis suggests that the risk may be related to contaminants such as polychlorinated biphenyls (PCBs), dioxins, and mercury found in fish meat, rather than the fish itself.

That said, certain types of fish are indeed unsuitable for long-term consumption, especially when prepared improperly. Incorrect cooking methods not only significantly reduce the nutritional value of fish but may also negatively affect health.

1. Salted Fish

Salted fish has long been classified by the World Health Organization as a Group 1 carcinogen, meaning it is known to cause cancer in humans.

The cancer risk mainly comes from nitrites produced when amines—formed during the curing and drying process—react with salt to create nitrosamines. Once ingested, these nitrosamines become highly potent carcinogens. Long-term excessive consumption of salted fish can lead to the accumulation of nitrosamines in the body, significantly increasing the risk of cancer.

When purchasing, it is recommended to choose salted fish produced by reputable manufacturers, as small workshops or homemade salted fish are often difficult to regulate in terms of safety. Nitrite levels can peak during the initial curing stage, posing higher risks. This does not mean salted fish must be completely avoided; occasional consumption in small amounts generally does not have a significant impact on health.

A Man’s Liver Riddled Like a Honeycomb Due to Frequently Eating One Type of Fish: Doctors Advise Eating These 4 Types of Fish as Little as Possible Because They Contain Carcinogens – Image 3

2. Freshwater Fish Sashimi

Raw freshwater fish is highly susceptible to infection with Clonorchis sinensis. This parasite can survive in the human body for a very long time—sometimes up to 20–30 years—causing severe damage to liver health. Over time, it may lead to cholecystitis, liver cirrhosis, and even cholangiocarcinoma (bile duct cancer).

3. Grilled Fish

Grilled fish typically requires cooking at very high temperatures. During this process, harmful substances such as benzopyrene and free radicals are produced, and carcinogens like heterocyclic amines may also form. Moreover, high-temperature cooking severely reduces the nutritional value of fish.

4. Fish Treated with Formaldehyde

Some unethical vendors add formaldehyde to fish to extend its shelf life, so careful inspection is necessary when purchasing. Fish soaked in formaldehyde tends to have unusually firm flesh, lacks elasticity, and emits a pungent odor, making it relatively easy to identify.