Alkylresorcinols (ARs) are a class of phenolic lipids present in high amounts in wheat bran and rye bran. The concentrations of ARs in whole wheat and whole rye are 320-1,430 mcg/g and 360-3,200 mcg/g, respectively, but these compounds are not present in refined flour. Because ARs are amphiphilic, they can form monolayers and be incorporated into phospholipid membranes. ARs have structural similarities to tocopherols and tocotrienols.

In the present study, rats were fed one of four different levels of ARs for 4 weeks: 0 (control), 1, 2, and 4 g/kg of diet. Compared with the control diet, each of the AR diets significantly increased the concentration of gamma-tocopherol in liver and lungs (p < 0.05). In vitro studies using HepG2 cells suggested that ARs increase the concentration of gamma-tocopherol by inhibiting its metabolism.

Comment: A growing body of evidence suggests that gamma-tocopherol (one of the naturally occurring forms of vitamin E), can help prevent heart disease and cancer. The capacity of a constituent of whole grains to increase tissue levels of gamma-tocopherol might explain in part the cardioprotective and anticancer effects of whole grains. Of course, the higher concentrations of magnesium, folic acid, vitamin B6, choline, betaine, zinc, copper, vitamin E, and fiber in whole grains than in refined flour presumably also play a role in the health benefits of whole grains. The more new biologically active components we discover in whole foods, the more it becomes apparent that we will never be able to duplicate nature with synthetic nutrient supplements.

Ross AB, et al. Cereal alkylresorcinols elevate gamma-tocopherol levels in rats and inhibit gamma-tocopherol metabolism in vitro. J Nutr 2004;134:506-510.