Alkylresorcinols are lipid polyphenols which structurally possess a long aliphatic chains with a polyphenolic resorcinol head. Alkylresorcinols are found in the bran of cereal grains of wheat, rye and barley, but are generally rare in nature and so present in no other commonly eaten foods. Evidence suggests that alkylresorcinols are bioavailable as plasma levels rise with increasing intakes. This has lead to suggestions that alkylresorcinols are a good biomarker for whole grain intake (here and here). Alkylresorcinols are rapidly metabolised following absorption and metabolites can be detected in plasma. The fate and biological activity of these metabolites has not been fully characterised, but evidence from other studies suggests that polyphenol metabolites may have favourable biological effects. As well as their presence in plasma, alkylresorcinol metabolites can also been detected in urine following whole grain intakes.
Whole grains have been reported to be protective of obesity in humans. This has been explained by their high fibre to carbohydrate ratios which may reduce their glycaemic effects. In addition, their high micronutrient content may also be protective of obesity by supplying nutrients such as chromium, which are required for the correct function of the insulin receptor. Further evidence that whole grains are protective of obesity, and the cardiovascular risk factors associated with abdominal obesity and the metabolic syndrome was recently published in the Journal of Nutrition1. In the study the researchers measured the plasma alkylresorcinol plasma concentrations of healthy adults aged 60-81 years. The results showed that plasma alkylresorcinol concentrations were associated with a lower body mass index in the subjects. In addition there was a dose dependent relationship between whole grain intake and plasma alkylresorcinol concentrations.
These results confirm previous studies in that there is a correlation between plasma alkylresorcinol concentration and whole grain intake from wheat. Plasma alkylresorcinol concentrations are therefore an effective biomarker for whole grain intake. In addition, the association between plasma alkylresorcinol concentration and a lower body mass index supports previous studies that show beneficial weight loss effects with higher intakes of whole grain cereals. Previous studies have shown higher plasma alkylresorcinol concentrations in men compared to women, but this study did not support these findings. This discrepancy may be explained by the age difference of subject between studies, although this is not exactly clear. This study also supports previous findings in that the whole grain intake of the elderly subject was low, possibly because they were community dwellers and their diet was therefore not of high quality.
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