Biomarkers of Whole Grain Wheat and Rye Intake

Alkylresorcinols (AR) are a group of lipids found in the bran fraction of wheat and rye grains. AR are absorbed into the bloodstream and their metabolites are excreted in urine in measurable amounts following ingestion of wholegrain (WG) wheat or rye cereal. As AR are absent in refined cereals, plasma AR and urinary AR metabolites are proposed as suitable biomarkers of dietary intake of WG wheat and rye cereal, with a number of studies supporting this proposal. Different AR species are present in characteristic quantities in WG wheat in comparison to WG rye cereals, which can allow identification of the main source of WG (wheat or rye) in individuals by analysing the AR concentrations in blood. However the patterns of urinary AR metabolite excretion following wheat or rye intake have not yet been investigated to determine if there are differences according to WG source.

The present study aims to:

(i) investigate the differences in AR metabolite excretion pattern in spot and 24 hour urine samples after following a predominantly WG rye-based diet in comparison to a predominantly WG wheat-based diet and in comparison to control (refined cereal diet) (ii) compare the validity and reproducibility of AR metabolites in spot urine samples in comparison to 24 hour urine samples.