TAIPEI, Taiwan - Long-term overeating of deep-sea fish, such as shark, sailfish and tuna, may lead to mercury poisoning, memory decline, infertility and other diseases. People can eat such fish once a month at most to avoid being harmed, according to a study released yesterday by Taipei Veterans General Hospital (TVGH).
The report, issued at an international seminar on poisoning diagnosis and treatment held yesterday morning by the Poison Control Center of TVGH, called for people not to eat the skin and viscera of such deep-sea fish and urged pregnant women and children to avoid eating such fishes.
In presenting her report at the seminar, Dr. Wu Ming-ling of the TVGH said that there were six children among a total of 31 related cases collected during the study period of 2007-2011 who were all plagued by language retardation and attention deficit hyperactivity disorder (ADHD). Of the 25 remaining adult patients, six suffered mercury poisoning, recording excessive mercury content in their blood and hair.
Wu cited a special case, showing that all five members of a family studied recorded extremely high mercury levels in blood and hair.
Of the five, the mother, aged 41, had thyroid gland disease and other chronic diseases. Her son, aged 5, saw a blood mercury level of 98.5ppb and a hair mercury content of 37.35ppm, all far higher than the optimum level of 5-10ppb and 1ppm, respectively, set by the World Health Organisation. The son was also confirmed to have ADHD.
Even worse was the daughter, aged 3, who recorded an even higher blood mercury level of 205.77 ppb, 40 times the optimum level and a likely cause of her language retardation.
Dr. Wu urged locals to eat deep-sea fish only once per month, at the most, lest they should suffer the aforementioned diseases.
But in the eyes of Tsai Jih-yao, deputy director-general of the Fisheries Agency under the Council of Agriculture, eating deep-sea fish every day is OK with normal adults if the amount is not excessive.
Tsai said that large-sized deep-sea fish have naturally accumulated higher mercury than other fishes which is not accumulated from exterior sources. Accordingly, it's safe for normal adults to have a reasonable amount of deep-sea fish every day, Tsai noted, adding that he eats deep-sea fish at lunch and dinner every day.