Volume 90, Issue 4, October (2003), pp. 787-794 © The Author 2003
doi:10.1079/BJN2003965

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Absorption of dietary alkylresorcinols in ileal-cannulated pigs and rats

Alastair B. Ross¹, Martin J. Shepherd², Knud Erik Bach Knudsen³, L. Vibe Glitsø³, Elizabeth Bowey⁴, John Phillips⁴, Ian Rowland⁴, Zhao-Xia Guo⁵, D. J. R. Massy⁶, Per Åman¹, Afaf Kamal-Eldin^1
1Department of Food Science, Swedish University of Agricultural Sciences (SLU), Box 7051, SE-750 07 Uppsala, Sweden
²CSL Food Science Laboratory, Norwich Research Park, Norwich NR4 7UQ and Institute of Food Research, Norwich, NR4 7UA, , UK
³Department of Animal Nutrition and Physiology, Danish Institute of Agricultural Sciences, PO Box 50, Research Centre Foulum, 8830 Tjele, Denmark
⁴BIBRA International, Carshalton, Surrey, UK
⁵School of Chemical Sciences, University of East Anglia, Norwich, NR4 7TJ, , UK
⁶Morello Close, Norwich, NR4 7NF, , UK

 (Received 5 March 2003–Revised 19 May 2003–Accepted 23 June 2003)

Alkylresorcinols (AR) are amphiphilic 1,3-dihydroxy-5-alkyl phenolic lipids. AR in food are only found in the outer layers of wheat and rye grains, and in whole grains are present at concentrations of 500–1000 μg/g. In wheat and rye, there are five main homologues, differing in the length of the odd-numbered alkyl chain (from seventeen to twenty-five C atoms long). Because AR may be bioactive, and might serve as biomarkers for these cereals, their absorption was investigated in model experiments with pigs and rats. Pigs with a cannula in the terminal ileum were fed four diets containing rye fractions with different levels of AR and the ileal effluents were analysed. The ileal recovery of AR was found to vary between 21 and 40 %, with no major difference between different chain-length homologues. The absorption of AR by rats was investigated by feeding ¹⁴C-labelled heneicosylresorcinol (C_21 : 0). Of the total activity, about 34 % was recovered in the urine, showing that the labelled AR was absorbed and metabolised by rats. AR were mostly cleared from rats by 60 h. It is concluded that AR are absorbed in the small intestine of single-stomached animals and excreted in metabolised form in the urine, and might contribute to the nutritional qualities of wholegrain wheat and rye diets.

Keywords:
Alkylresorcinols, Ileal absorption, Wholegrain rye

Abbreviations:
AR, alkylresorcinols