Leptin and phospholipid-esterified docosahexaenoic acid concentrations in plasma of women: observations during pregnancy and lactation

Background: The n-3 fatty acid status changes during pregnancy and lactatio n. Plasma leptin concentrations and gene expression have been related to n- 3 fatty acids. Objective: To investigate the relation between plasma leptin concentration and the docosahexaenoic acid (22:6n-3) content of plasma phospholipids duri ng early pregnancy and the postpartum period. Design: Leptin (radioimmunoassay) and the phospholipid fatty acid profile ( capillary gas-liquid chromatography) were measured in plasma of women durin g two independent longitudinal observational studies. Dietary intake of n-3 fatty acids was also determined. Results: Within the first 10 weeks after the last menstrual period, an almo st parallel increase in leptin concentration and the 22:6n-3 content (mg/l and % wt/wt) of plasma phospholipids was seen (study 1, n =21). During the postpartum period (study 2, n = 57), leptin levels decreased quickly, prece ding the changes in 22:6n-3 concentrations. During both studies, leptin con centrations did not consistently relate to dietary intake of n-3 fatty acid s or to 22:6n-3 concentrations in plasma phospholipids. Before and during e arly pregnancy (study 1), significant positive associations between leptin revels and the total amount of phospholipid-associated fatty acids were fou nd. No such association was seen during late pregnancy or the postpartum pe riod (study 2). The postpartum decrease hi leptin levels did not differ bet ween lactating and non-lactating women. Conclusions: Not the 22:6n-3 content, but the total amount of phospholipid- associated fatty acids was related to plasma leptin concentration, before a nd during early pregnancy but not during late pregnancy and the postpartum period. Sponsorship: Dutch Organization for Scientific Research (NWO, grant no. 904 62 186).