Search

Background: Interindividual differences in the bioavailability of potentially carcinogenic estrogen and estrogen metabolites (EMs) may play a role in the risk of breast cancer., Objective: We examined whether dietary intakes of fiber and fat influence premenopausal EM profiles through effects on estrogen synthesis, metabolism, or excretion., Methods: We conducted a cross-sectional analysis of 598 premenopausal women who participated in a reproducibility study (n = 109) or served as controls in a nested case-control study of breast cancer (n = 489) within the Nurses' Health Study II. Dietary intakes of fiber and fat were assessed via semiquantitative food frequency questionnaires in 1995 and 1999. Midluteal urine samples were collected between 1996 and 1999 and EMs were quantified with the use of HPLC-tandem mass spectrometry. Linear mixed models were used to estimate creatinine-adjusted geometric means for individual EMs and their pathway groups across categories of dietary intake while controlling for total energy intake and potential confounders., Results: Higher total dietary fiber intake (>25 g/d vs. ≤15 g/d) was associated with significantly higher concentrations of 4-methoxyestradiol (50% difference, P-difference = 0.01, P-trend = 0.004) and lower concentrations of 17-epiestriol (-27% difference, P-difference = 0.03, P-trend = 0.03), but was not associated with any other EMs. The associations did not vary by fiber intake from different sources. Total fat intake (>35% energy vs. ≤25% energy) was suggestively positively associated with 17-epiestriol (22.6% difference, P-difference = 0.14, P-trend = 0.06); the association was significant for polyunsaturated fatty acid (37% difference, P-difference = 0.01, P-trend = 0.01) and trans fat (36.1% difference, P-difference = 0.01, P-trend = 0.01) intakes., Conclusion: Fiber and fat intakes were not strongly associated with patterns of estrogen metabolism in premenopausal women. Our data suggest estrogen metabolism is not a major mechanism through which dietary fiber and fat may affect breast or other hormone-related cancer risks., (© 2015 American Society for Nutrition.)

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., (Copyright (c) 2006 S. Karger AG, Basel.)