Dietary phospholipid carriers of DHA do not increase brain DHA levels: a replication study

DHA is primarily found in fish and seafood as triacylglycerols and phospholipids (PLs). Oral administration of PL DHA forms, sn-1 lysophosphatidylcholine-DHA (sn-1 LPC-DHA) and di-DHA phosphatidylcholine (di-DHA-PC), has been suggested to increase brain DHA levels by ∼100% (relative percent) and up to ∼200% (concentration) compared with controls. In contrast, triacylglycerol-DHA and nonesterified-DHA do not produce increases in brain DHA when provided in the diet. However, a subsequent study using a higher dose of sn-1 LPC-DHA did not confirm these findings and reported no significant increase in brain DHA. To address these inconsistencies, we aimed to replicate previous investigations of PL-DHA forms (LPC and PC) and their impact on brain DHA levels. Mice were randomly divided into one of four groups and received a daily gavage for 30 days of 80 μl of either corn oil alone (control) or corn oil containing 1 mg of DHA as nonesterified DHA, sn-1 LPC-DHA, or di-DHA-PC. DHA relative percent and concentrations were determined in brain regions (cortex, cerebellum, hippocampus, amygdala, striatum, and remainder of brain) and plasma using GC-flame ionization detection. Following treatment, no significant differences in DHA relative percent or concentration were observed between control and/or treatment groups in any brain region. Relative percent of plasma DHA was significantly elevated in all DHA-treated groups compared with the control group, confirming systemic absorption of the supplemented DHA. Our results demonstrate that dietary DHA provided as sn-1 LPC-DHA or di-DHA-PC does not increase brain DHA levels compared with nonesterified-DHA or the control group, failing to reproduce prior reports.