Black tea

Black tea is one of the foods a review of natural salicylates names among the major sources in the British diet, alongside tomato-based sauces, fruit and fruit juice, wine, herbs and spices, and steeping time is the lever people forget: a longer brew pulls more salicylate into the cup than a short one. Neither study publishes a value for this particular drink.

Black tea contains no histamine, and it is here for the third route on this axis: tea polyphenols inhibit DAO, the enzyme that breaks histamine down in the gut. Drinking it alongside a histamine-rich meal is worse than drinking it alone. Brückner infused 14 black teas among 21 and detected no histamine in any of them; two of the black teas carried no measurable amine at all, and tyramine across the set ran 16 to 431 micrograms per litre of infusion. The histamine half of the case is measured and empty. What keeps black tea on this axis at all is the other half — the enzyme that clears histamine — and that has not been measured.

Black 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.

Black tea is the fully oxidised leaf, and oxidation changes the polyphenols without touching the mineral content. Steeping longer pulls out a little more; a strong brew is the only version that moves the needle. 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.

Black 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.