Erythrocyte membrane phospholipid composition as a biomarker of dietary fat

Background/Aims: In a cross-sectional study, we investigated the relationship between erythrocyte membrane phospholipid fatty acid composition and dietary fat; we also investigated roles of menopausal status, age, body mass index (BMI) and waist-to-hip ratio (WHR) in interindividual variation of the biomarker. Methods: Study participants were 204 women, aged 39-65 years, drawn from the ORDET cohort and selected as controls in a study of breast cancer. Membrane composition was assessed using capillary gas chromatography. Dietary fat composition was evaluated using a food frequency questionnaire. Results: In pre- and postmenopausal women, erythrocyte membrane phospholipid levels of linoleic acid, oleic acid, and mono-unsaturated fatty acids were significantly associated with corresponding dietary measures (partial correlation coefficients: 0.23 and 0.39; 0.45 and 0.47; 0.40 and 0.48; respectively, in pre- and postmenopausal women). Among postmenopausal women, membrane poly-unsaturated fatty acids were correlated with the corresponding dietary measure (r = 0.39, p < 0.001). Membrane eicosapentanoic and docosahexanoic acid levels were significantly correlated with intake of fish/shell fish:r = 0.21 and r = 0.43 (premenopausal), and r = 0.41 and r = 0.44 (postmenopausal). Age, BMI and WHR had independent effects on membrane lipid composition. Age was associated with delta-6 desaturase activity in postmenopausal women (r = 0.25, p < 0.05). BMI was negatively associated with delta-9 desaturase activity in both pre- and postmenopausal women (r = -0.29, p = 0.01 and r = -0.22, p < 0.01, respectively). WHR was negatively associated with delta-5 desaturase activity in pre-menopausal women (r = -024, p < 0.05). Conclusions: Erythrocyte membrane levels of some specific fatty acids can be used as biomarkers of these fatty acids as proportions of dietary fat.