Whole-grain rye and wheat alkylresorcinols are incorporated into human erythrocyte membranes

Alkylresorcinols (AR), a group of phenolic lipids, exist in the human diet in whole-grain rye and wheat. They are absorbed by humans and have been quantified in plasma. In this 2-week study we assessed AR incorporation into human erythrocyte membranes. Nine subjects attended the study; four avoided whole-grain products for 1 week and then included whole-grain rye and wheat bread in the diet for the second week, four included whole-grain rye and wheat products in the diet during the whole follow-up and one followed a gluten-free diet. Plasma and erythrocyte membrane AR were analysed after weeks 1 and 2. Erythrocyte membrane AR concentrations increased an average of 231 nmol/l of packed erythrocytes (P=0·036) after consumption of whole-grain rye and wheat products. Plasma AR levels increased an average of 175 nmol/l (P=0·058) When intake of whole-grain products was constant, erythrocyte membrane and plasma AR levels remained stable. Long-chain AR were incorporated into erythrocyte membranes in a higher proportion compared to shorter-chain AR. This preliminary study shows that AR are incorporated into human erythrocyte membranes in vivo.