Oat fiber

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

Oat fiber contains only low levels of FODMAPs. Oat fibre is the hull, not the groat: cellulose rather than fructan, which is why it reads lower than the oats it comes from. The survey behind this axis's grain figures measured oats at 0.11 g per portion and did not measure the hull at all, so that 0.11 is the ceiling for this product rather than its value.

Oat fiber contains only low levels of gluten. Oat fibre is the hull rather than the groat - the outer husk, milled for its insoluble fibre - and the hull is the part most exposed to whatever else was in the field and the store. It is added in small percentages to bread and bars, including gluten-free ones. Certification answers contamination and not everything else: both associations say uncontaminated oats suit MOST coeliacs rather than all, because a minority react to the avenin itself.

Oat fiber contains only low levels of oligosaccharides. Oat fibre is the hull, and the hull is cellulose and beta-glucan - long chains that ferment slowly and evenly rather than the short oligosaccharide chains. Beta-glucan is the fibre oats are sold for, and it is not a FODMAP.

Oat fiber contains only low levels of nickel. Oat fibre is the hull rather than the grain - the woody outer layer, isolated. It carries the nickel the outside of the plant collected, but it is used in small amounts as a bulking agent. Amounts vary by brand and recipe, so always check the label of the exact product.