ALKYLRESORCINOLS

Alkylresorcinols are phenolic lipids present in the outer parts of rye and wheat kernels (Ross et al. 2001). They are considered to be inhibitory components responsible for lowering feed intake, feed conversion efficacy and growth rate in animals fed rye diets. As a result of this belief, selection programmes for rye cultivars with low levels of alkylresorcinols were started in an effort to increase the proportion of rye in animal feed. Interest in alkylresorcinols, however, continued and a wide range of activities, including antimicrobial, antiparasitic, antitumour and antioxidant effects, were attributed to them. (Ross et al. 2001, Kamal-Eldin et al. 2000, Kozubek and Tyman 1999).

Alkylresorcinols have been found to be absorbed ry rats (Ross et al. 2003), pigs (Ross et al. 2001) and humans (Linko et al. 2002; Ross et al. 2003; Linko et al. 2005), but little is known about their metabolism or the resulting metabolites. Deconjugated human urine after the wheat-bran based meal was shown to contain two alkylresorcinol metabolites, 3,5-dihydroxybenzoic acid and 3-(3,5-dihydroxyphenyl)-1-propanoic acid, as well as smaller amounts of unchanged alkylresorcinols, confirming the hypothesis that alkylresorcinols are metabolised in humans via b-oxidation of their alkyl chains (Ross et al. 2004).

Because alkylresorcinols are present in high amounts in whole grain wheat and rye but not in appreciable amounts in other foods, Ross and co-workers (Chen et al. 2004; Ross et al. 2005) have proposed that alkylresorcinols could be candidates as biomarkers of wholegrain intake from wheat and rye. According to their estimation of the intake of alkylresorcinols in Scandinavian and the UK using food supply data, the UK had the lowest (11.9 mg/day), Sweden (17.5 mg/day) and Norway (18.5 mg/day) had moderate, while Finland (39.8 mg/day) and Denmark (37.1 mg/day) had the highest intake of alkylresorcinols (Ross et al. 2005). According to this study 95 % of all Swedes consumed some alkylresorcinols, as compared with 50 % of British people surveyed.


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