Tea

Tea is the entry that covers both black tea and green tea, and its answer here is theirs. Brückner infused 21 teas — 14 black, 5 green, one Oolong, one instant — and detected no histamine in any of them; tyramine ran 16 to 431 micrograms per litre of infusion, and in three teas no amine was found at all. The authors expect no health risk even from large quantities. That settles the histamine question and not the other one: this axis also covers what slows the enzyme clearing histamine, and that has not been measured.

Tea carries measurable amines in the leaf, but an infusion transfers only part of what a plant holds into the water and the leaf is discarded. Note the contrast with the histamine axis, where tea is listed for inhibiting the DAO enzyme - tyramine is cleared by MAO instead, which tea does not touch.

Green and lighter teas are lower in salicylate than black tea, which is high. Steeping time is the lever: a short brew pulls out considerably less than a long one.

The tea plant accumulates metals from acidic soil, but the cup does not: brewing extracts only part of what the leaf holds, and the leaf is thrown away. What ends up in the water is a fraction of what was in the plant. What matters for a leaf you steep rather than eat was measured directly: the study behind this level analysed the herb AND its water infusion, and most of the nickel stays in the leaf. The cup is not the plant.

Tea carries oxalate in the leaf, but a cup is a dilute infusion and the leaf is discarded - most of what the plant held never reaches the water. Volume is the variable: several strong cups a day is a different exposure from one weak one, and adding milk brings calcium that binds part of what did dissolve. Noonan puts a number on that: English diets take in 70 to 150 mg of oxalate a day, and TEA is the largest single contributor of it — which is how a dilute infusion ends up at the top of a diet without being high in a cup.