Cranberry

Cranberry is eaten almost entirely in concentrated forms — juice and dried — which carry more per mouthful than the fresh berry. The sweetened versions hide the sourness, not the salicylate.

Cranberry carries its sugars in balance - glucose keeping pace with fructose - so there is no excess left unabsorbed. Berries are the fruit group a low-FODMAP diet keeps, with blackberry the exception, which is high in sorbitol rather than fructose.

Cranberry is low on this axis because of more glucose than fructose, unusually for a berry. 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.

Cranberry is low in oxalate as a fruit, but almost nobody eats it as a fruit: it arrives as juice, as sauce, or dried and sweetened, and each form is a different serving. The dried berries keep company with raisins, the juice with drinks - the question follows the form.

Cranberries grow in acidic bogs, which mobilises metals - yet they still measure low, because the fruit itself takes up very little. Dried sweetened cranberries concentrate what there is. No measurement of cranberry nickel is published: the berry study behind this axis covers lingonberry, blueberry and rose hip, and the lingonberry is a different Vaccinium from the cranberry.

Cranberries are too sharp to eat raw in quantity; the dried and juiced kinds are other entries.