Rye flour

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

Yes — rye flour is high in FODMAPs. Rye flour concentrates a grain that was already the highest of the cereals in FODMAPs, and it is used in dense breads eaten in thin slices - which is the only thing working in its favour. A single slice of pumpernickel is a smaller dose than a sandwich made of wheat bread.

Yes — rye flour is high in oligosaccharides. Same reason as the FODMAP level: rye fructans, concentrated by milling into a flour used for dense breads. The thin slice such breads are cut into is the only thing limiting the dose.

Yes — rye flour is high in gluten. Rye flour contains gluten. It is also almost never used alone - rye bread is usually a rye and wheat blend, because rye on its own gives too little structure. Either grain answers this question the same way.

Rye flour contains only low levels of nickel. Rye flour is milled from a low-nickel grain, and a dark rye flour keeps more of the bran the metal sits in than a light one does. Two national surveys put bread and cereals among the groups that deliver most of the dietary nickel — near the top because they are eaten in quantity rather than because they are concentrated, and neither publishes a figure for a single grain. Amounts vary by brand and recipe, so always check the label of the exact product.