Tofu

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

Yes — Tofu is high in nickel. Tofu was the single highest-nickel food group in the French Total Diet Study - above shellfish, above dark chocolate. Pressing soy milk into a block concentrates what the bean took up, and tofu is eaten as a main portion rather than a garnish.

Tofu contains only low levels of FODMAPs. Tofu is low although the soybean is one of the highest-GOS foods there is, because it has been pressed, and the GOS left in the whey that was squeezed out. Soy is the clearest illustration on this axis that processing decides the level rather than the plant: the same bean gives natto at the top and this at the bottom.

Tofu contains only low levels of histamine. Tofu is pressed, unfermented soy - the curd is set with a mineral salt and eaten fresh. Fermented tofu is another food entirely and sits at the top of the histamine range; the two share a name and nothing else here.

Tofu contains only low levels of oligosaccharides. Tofu is pressed, and pressing removes the whey - which is where the water-soluble GOS go. That is why firm tofu is low while the bean it came from is high, and why silken tofu, which is not pressed, is not the same food here. Amounts vary by brand and recipe, so always check the label of the exact product.