Is octopus vegetarian-compatible?

What to know about octopus

Octopus is a cephalopod mollusc, and on food chemistry it is a fairly quiet food: moderate for histamine, moderate as a histamine liberator, moderate for tyramine, and clean on everything else we track. No gluten, no lactose, no FODMAPs, no salicylate, no oxalate, no nickel, no nightshade, no added sulfites or nitrites. Nutritionally it is one of the leanest high-protein foods on the chart, roughly 30 g of protein and about 2 g of fat per 100 g cooked. The reason octopus shows up in trigger journals is usually one of two things that have nothing to do with its grades. The first is allergy: octopus is a mollusc, and along with squid it is one of the most commonly reported cephalopod allergens, driven by tropomyosin, which cross-reacts across molluscs and often with shrimp and crab. The second is handling. Octopus muscle is dense with collagen, so it needs either a long slow braise or the freeze-and-thaw trick that ruptures the connective tissue with ice crystals. That means most octopus you buy has already been frozen, often already cooked, and has spent hours in a warm pot. Histamine forms before cooking and survives it, so a long simmer cannot undo a bad cold chain.