Whole wheat flour

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

Yes — whole wheat flour is high in gluten. Wholemeal wheat flour keeps the bran and germ, which changes its fibre and its mineral content but not its gluten. Whole grain and gluten-free are unrelated claims that shelf labels often place side by side.

Whole wheat flour contains moderate levels of FODMAPs. Wholemeal flour keeps the bran and the germ, and it measures slightly higher in FODMAPs than white for the same weight. The gap is small - smaller than most people expect from how differently the two are marketed - and it is portion size, not the choice between them, that decides the outcome. Across the bread aisle the brand decides more than the type, gluten-free loaves included.

Whole wheat flour contains moderate levels of oligosaccharides. Same reason as the FODMAP level: wheat fructans, with the bran and germ kept. The gap between wholemeal and white is small here - it is the amount of flour in the food, not the type, that moves the number.

Whole wheat flour contains moderate levels of oxalates. Wholemeal flour keeps the bran and therefore the oxalate that white flour has lost, and the bran is where it concentrates: 457.4 mg per 100 g against 53.3 to 76.6 for the whole grain. The difference between a wholemeal loaf and a white one is real on this axis and small on most others, which is worth knowing before choosing the brown bread on principle. Amounts vary by brand and recipe, so always check the label of the exact product.