Alkylresorcinol

Alkylresorcinols are phenolic lipids present in high amounts in the bran layer (e.g. pericarp, testa and aleurone layers) of wheat and rye (0.1-0.3 % of dry weight). They are not present in the endosperm (the part of cereal grain that is used to make white flour), which means that alkylresorcinols can be used as 'biomarkers' for people who eat foods containing wholegrain wheat and rye, rather than cereal products based on white flour.[1] Increasing evidence from human intervention trials suggests that they are the most promising biomarker of whole grain wheat and rye intake.[2][3] Alkylresorcinol metabolites, 3,5-dihydroxybenzoic acid (DHBA) and 3,5-dihydroxyphenylpropionoic acid (DHPPA) were first identified in urine[4] and can be quantified in urine[5] and plasma[6], and may be an alternative, equivalent biomarker of whole grain wheat intake.[7]

Alkylresorcinols were thought to have anti-nutrative properties (e.g. decreasing growth of pigs and chickens fed rye), but this theory has been discredited, and a number of animal studies have demonstrated that they have no obvious negative effect on animals or humans.[1] In vitro studies have shown that alkylresorcinols may prevent cells turning cancerous, but that they do not have any effect on cells that are already cancerous.[1] Alkylresorcinols also increase gamma-tocopherol levels in rats when fed in high amounts (0.2 % of total diet and above.[8]

The average intake of alkylresorcinols in the UK is around 11 mg/person/day, and in Sweden is around 20 mg/person/day.[9] This varies widely depending on whether people normally consume wholegrain/wholemeal/brown bread, which is high in alkylresorcinols (300-1000 µg/g), or white wheat bread, which has very low concentrations of alkylresorcinols (<50 µg/g).

Sources

  1. ^ a b c Ross AB, Kamal-Eldin A, Åman P. (2004) Dietary alkylresorcinols: absorption, bioactivities, and possible use as biomarkers of whole-grain wheat- and rye-rich foods. Nutr Rev. 62(3):81-95. PubMed
  2. ^ Landberg R, Kamal-Eldin A, Andersson A, Vessby B, Åman P. (2008) Alkylresorcinols as biomarkers of whole-grain wheat and rye intake: plasma concentration and intake estimated from dietary records. Am J Clin Nutr. 87(4):832-8. PubMed
  3. ^ Landberg R, Kamal-Eldin A, Andersson SO, Johansson JE, Zhang JX, Hallmans G, Aman P. (2009) Reproducibility of plasma alkylresorcinols during a 6-week rye intervention study in men with prostate cancer. J Nutr. 139(5):975-80. PubMed
  4. ^ Ross AB, Åman P, Kamal-Eldin A. Identification of cereal alkylresorcinol metabolites in human urine-potential biomarkers of wholegrain wheat and rye intake. J Chromatogr B Analyt Technol Biomed Life Sci. 2004 Sep 25;809(1):125-30. PubMed
  5. ^ Koskela A, Linko-Parvinen AM, Hiisivuori P, Samaletdin A, Kamal-Eldin A, Tikkanen MJ, Adlercreutz H. (2007) Quantification of alkylresorcinol metabolites in urine by HPLC with coulometric electrode array detection. Clin Chem. 53(7):1380-3. PubMed
  6. ^ Koskela A, Samaletdin A, Aubertin-Leheudre M, Adlercreutz H. (2008) Quantification of alkylresorcinol metabolites in plasma by high-performance liquid chromatography with coulometric electrode array detection. J Agric Food Chem. 56(17):7678-81. PubMed
  7. ^ Aubertin-Leheudre M, Koskela A, Marjamaa A, Adlercreutz H. (2008) Plasma alkylresorcinols and urinary alkylresorcinol metabolites as biomarkers of cereal fiber intake in Finnish women. Cancer Epidemiol Biomarkers Prev. 17(9):2244-8. PubMed
  8. ^ Ross AB, Chen Y, Frank J, Swanson JE, Parker RS, Kozubek A, Lundh T, Vessby B, Aman P, Kamal-Eldin A. (2004) Cereal alkylresorcinols elevate gamma-tocopherol levels in rats and inhibit gamma-tocopherol metabolism in vitro. J Nutr.134(3):506-10. PubMed
  9. ^ Ross AB, Becker W, Chen Y, Kamal-Eldin A, Åman P. (2005) Intake of alkylresorcinols from wheat and rye in the United Kingdom and Sweden. Br J Nutr. 94(4):496-9. PubMed