Reading a recent news article about a Dutch fish processing firm using Sodium Nitrite for white fish processing I learned that the additive is associated with a higher risk of cancer when used in processing white fish. An English source states:
Sodium nitrite is cleared for use in meat products but is considered to be potentially cancer-causing when used with fish.
Reading into why sodium nitrite would be harmful in combination with fish, but not with other foods, I couldn't find much except broader warnings against eating foods with e250, especially for pregnant women. E.g.:
Health effects are acute methemoglobinemia (haemoglobin loses its ability to carry oxygen). Early symptoms include irritability, lack of energy, headache, dizziness, vomiting, diaorrhea, laboured breathing and a blue-gray or pale purple colouration to areas around the eyes, mouth, lips, hands and feet (blue baby syndrome).
Side effects/ Connected to; Irritability, lack of energy, headaches, dizziness. Pregnancy complications, Infant health problems; Linked with Leukaemia, many cancers such as colon, bladder, stomach, thyroid etc.
Wakingtimes (emphasis mine)
Are these warnings against eating anything with e250 scientifically justified, or is it all baloney (nudge nudge)? If so, why is it that it is banned for use in processing fish, but not meats?