Buckwheat

Buckwheat is notable for nickel, oxalates, histamine and salicylate. Clear on tyramine, sucrose, FODMAPs, lactose, oligosaccharides, sorbitol, fructose and gluten.

Yes — buckwheat is high in nickel. Buckwheat is not a wheat but a seed, and it carries a nickel load closer to the legumes than to the cereals. Its use as a gluten-free substitute means people often increase it sharply without knowing.

Buckwheat contains moderate levels of oxalates. Buckwheat is not a wheat and not a grass - it is a seed related to rhubarb and sorrel, which is the family this axis is named after. That relation is not a coincidence: the plants that store oxalate tend to be related, and buckwheat sits with them.

Buckwheat contains only low levels of histamine. Buckwheat is a seed rather than a cereal, eaten as groats or as flour, and neither form has a fermentation step — which is where histamine comes from. Where it becomes a question is what the flour turns into: a long-fermented dough is a different food from the flour it started as.

Buckwheat contains only low levels of salicylate. Buckwheat: low in salicylate, and one of the useful gluten-free grains that stays low here too — a combination that is not always available. Amounts vary by brand and recipe, so always check the label of the exact product.