The WHO has recently issued a new list of carcinogenic food which categorizes Chinese-style salted fish as a Group 1 carcinogen, alongside tobacco, alcohol and betel nuts.
According to the head of Linkou Chang Gung Memorial Hospital’s Department of Toxicology Yen Tzung-hai, salted fish is preserved through salting and smoking, just like sausages, ham, bacon and other processed meats, all of which are carcinogens. This is mainly because nitrite, a constituent common to them all, will form nitrosamine when in contact with high temperatures and when absorbed by the stomach and intestines.
However, Yen notes that the WHO report is only referring to salted fish to which nitrite has been added, that not all salted fish is carcinogenic, and that adding nitrite to food is legal. The cancer risks cited in the report are relative rather than absolute, and the risks can easily be reduced by eating less salted fish, so there is no need to be overly worried, Yen says.
Yen says that salted fish usually contains high levels of sodium, since large amounts of salt are often added, potentially increasing the risk of cardiovascular diseases. People should avoid eating too much salted fish and when they do, it is advisable this is accompanied with fresh fruit and vegetables, especially those rich in vitamin C and other antioxidants, to prevent the formation of nitrosamine.
Source article: http://www.taipeitimes.com/News/lang/archives/2017/11/26/2003682906