Herring (in tomato sauce)

This product combines canned or pickled herring with tomato sauce, and both components independently contribute to a high histamine load.

• Preserved herring — canned or pickled herring already carries elevated histamine from the preservation process; this is the base concern before the sauce is even considered

• Tomato as a compounding factor — tomatoes are a well-established histamine liberator and are also listed as a histamine-containing food in several reference sources, though their direct histamine content is debated; either way, combining them with preserved fish means you're getting histamine pressure from multiple directions

For people managing histamine carefully, this is one of those combinations where the parts add up to more than the whole.