Wheat bran

Wheat bran is notable for gluten, oxalates, FODMAPs and oligosaccharides. Clear on histamine, tyramine, salicylate, sucrose, lactose, sorbitol, fructose and nickel.

Yes — wheat bran is high in gluten. Wheat bran is the outer layer of the grain, sold for its fibre - and the fibre is exactly why it gets added to foods that are otherwise nothing to do with wheat: breakfast cereals, biscuits, supplements. The gluten comes with it whatever the reason it is there.

Wheat bran contains moderate levels of oxalates. Wheat bran is where the grain's oxalate and its phytate both sit, and the second matters as much as the first because phytate binds calcium, and calcium bound to phytate is calcium not available to bind oxalate. Bran works against the standard remedy for this axis. Israr measured both in the same samples: across wheat, barley and oat bran, total oxalate ran 33 to 199 mg/100 g and the soluble part 14 to 79, with phytate from 227 to 4,393 mg/100 g — enough, in every food tested, to raise the soluble share by binding up the calcium. The soluble part does not follow the total, which is why the phytate matters. Two published figures for wheat bran do not agree: Siener measured it alone at 457.4 mg per 100 g, several times Israr's range for a set of three brans.

Wheat bran contains only low levels of FODMAPs. Wheat bran is concentrated fructan, and it is low here only because a spoonful is a spoonful. It was not measured in the survey behind this axis's grain figures - 55 products, bran not among them - so the level is a judgement about serving size and not a published number. Two tablespoons on cereal is a different food from bran baked into a loaf.

Wheat bran contains only low levels of oligosaccharides. Wheat bran is the outer layer, and it carries fructans along with the fibre it is sold for. It stays low only because it is used by the spoonful - a serving of bran cereal is not a spoonful, and it answers differently. Amounts vary by brand and recipe, so always check the label of the exact product.