Apple

Apple fails twice over: it holds more fructose than glucose, and it carries sorbitol as well. Two of the five FODMAP families in one fruit, which is why no serving size rescues it and why apple is usually the first thing removed. Cooking concentrates rather than helps. The sugars behind this were measured on this fruit, in a study of four - peach, apple, watermelon and cherry - by HPLC. What it settles for this axis is presence and absence rather than a level: sorbitol was found in peach, apple and cherry and not in watermelon, and sucrose in peach, apple and watermelon and not in cherry. It publishes ranges across the four, never a value for one, so it cannot set a FODMAP level by itself. The same measurement answers here: Muir puts the apple among five fruits of 41 with more fructose than glucose, and that excess is the F of FODMAP rather than a separate finding.

Apple is the reference case for excess fructose: it carries roughly twice as much fructose as glucose, and it is the ratio that decides, not the total. Glucose ferries fructose across the gut wall, so a fruit that runs short of glucose leaves fructose behind to ferment. Muir names it in the measurement rather than by reputation: apple, pear, mango, clingstone peach and watermelon were the five that came out with fructose in excess of glucose across 41 fruits analysed by HPLC-ELSD. Being on that list of five is what this level means. The sugars here were separated and measured rather than looked up: across the four fruits in that study - peach, apple, watermelon and cherry - fructose ran 5.79 to 104.01 mg per gram, glucose 9.25 to 99.62 and sucrose 15.82 to 106.39. Those are RANGES across four fruits, not a value for this one, which is the honest limit of what an abstract gives.

Apple is the textbook case: it carries sorbitol AND more fructose than glucose, so two FODMAP mechanisms land at once. Cooking concentrates it rather than removing it - polyols are heat-stable. Ma measured that sorbitol rather than inferring it: the apple is one of four fruits separated by HPLC-ELSD, and across the three of them that carry sorbitol at all the values ran 8.70 to 19.13 mg per gram — a range over the three, not a figure for the apple.

Apple does carry sucrose, and it was measured rather than assumed: it is one of the three fruits in which sucrose was found in the study behind this axis, on a range of 15.82 to 106.39 mg per gram across four fruits. That is a RANGE over four fruits and the abstract publishes no value for any one of them - the measurement establishes presence, not amount.

The flesh is low, the skin is not — peeled apple is a very different food for salicylate from an apple eaten whole. Ripe fruit is also lower than underripe. Malakar measured exactly that difference: 2.93 mg/kg in the peeled apple against 9.03 unpeeled — three times as much in a fruit most people eat with the skin on. The authors' own conclusion from 112 foods is that serve size decides more than concentration does, which is the reason an apple stays low and a handful of dried herbs does not.

An apple is eaten out of hand, weeks after picking, and keeps without fermenting.

Apple carries no nickel worth counting here, and it is one of the five fruits Nie sampled to establish that. The study measured lead, cadmium, chromium and nickel in fruit from China's main growing areas; nickel led the four metals, but 97.5 per cent of samples stayed inside the permissible limits. It names the jujube and the peach as its highest and the grape as its lowest, and puts the apple in neither group, publishing no figure for it on its own.