Pineapple

Pineapple is high in salicylates, and canned or juiced forms are no lower — processing does not break salicylate down the way it breaks down some vitamins.

Pineapple is a liberator, and it carries bromelain, a protein-digesting enzyme strong enough to sting the mouth and to be sold as a meat tenderiser. Whether the enzyme adds to the effect is not settled, but it is the reason pineapple feels different from the citrus fruits it is grouped with. It is one of the five fruits the current review names as reported to trigger the release of endogenous histamine, and the review says plainly that the mechanism responsible has not yet been elucidated.

Pineapple is one of the few fruits where sucrose leads rather than glucose or fructose. That makes it mild on the fructose axis and not here: that axis counts fructose in excess of glucose, and this one counts sucrose.

Pineapple is one of the few fresh fruits with a measurable nickel load - the plant grows in acidic tropical soil, which mobilises metals that neutral soil holds onto. Canned pineapple adds a second source, because the tin itself leaches nickel into what it holds. No published assay covers the fruit; what is known is the soil the plant grows in.

Pineapple carries little tyramine. Fresh or canned, nothing in the way it is prepared ferments it - a pineapple left to go soft is spoiling, which is a different process from curing.

Pineapple is low with a qualification worth knowing: sucrose-led rather than fructose-led. Fruit is where this axis is least intuitive, because sweetness and FODMAP load are not the same measurement - what counts is the balance between the sugars, not how much sugar there is.

Pineapple is low on this axis because of sucrose-dominant rather than fructose-dominant. Fructose only causes trouble when it outruns glucose - glucose is what carries it across the gut wall, so a balanced fruit is absorbed even when it tastes sweet.