Non‐targeted urine metabolite profiling has not been previously exploited in the field of whole grain (WG) products. WG products, particularly rye, are important elements in a healthy Nordic diet. The aim of this study was to identify novel urinary biomarkers of WG rye bread (RB) intake in a randomised crossover study with RB versus refined wheat bread (WB).

UPLC‐QTOF/MS metabolite profiling was applied to urine from a 2 × 4 wk crossover intervention with RB versus WB in 20 subjects. Sixteen metabolites were revealed as major contributing biomarkers. The most discriminative metabolite after the cereal intervention was identified as 3‐(3,5‐dihydroxyphenyl)‐1‐propanoic acid sulphate, which was excreted to a higher extent after the RB versus WB intervention. Other alkylresorcinol metabolites were identified, as well as enterolactone glucuronide, azelaic acid, 2‐aminophenol sulphate and its benzoxazinoid precursor 2,4‐dihydroxy‐1,4‐benzoxazin‐3‐one. Our study also suggests that nitrogen‐containing metabolites are other major markers. However, other methodologies will be needed to elucidate their final structure.

The present non‐targeted metabolite profiling proved to be a useful approach to identify major urine metabolites discriminating RB intake from that of white wheat bread. Once validated these markers could help evaluate compliance to healthy Nordic diets.