High sn-2 DHA in Dietary Triglyceride Enhances Cognitive Performance of Mice

Docosahexaenoic acid (DHA), one of the most critical polyunsaturated fatty acids, is vital for the neurological growth and cognitive function of infants and children. Approximately 98% of DHA in breast milk exists as triglycerides, with 60% esterified at the sn-2 position. To demonstrate the necessity of mimicking the form of DHA present in breast milk in nutritional food for young children, this study administered diets with varying sn-2 DHA contents (10%, 30%, and 50%) to four groups of mice and analyzed their behavioral performance, brain DHA concentration, expression of brain fatty acid transport proteins, histopathology, and expression of synaptic-related proteins in the hippocampus after 4 weeks. The results showed that compared with the control group, mice in the 50% sn-2 DHA group exhibited superior learning and memory capabilities in behavioral tests, with the most pronounced behavioral improvements in mice, which correlated with higher brain DHA accumulation (from 0.870 ± 0.055 mg/g brain to 1.809 ± 0.132 mg/g brain, p < 0.05), increased levels of MFSD2A (1.40-fold, p > 0.05), FABP5 (2.36-fold, p < 0.05), FATP1 (1.47-fold, p < 0.05), and ACSL6 (1.48-fold, p < 0.05), improved hippocampal neuron morphology, and enhanced the level of BDNF (1.55-fold, p < 0.05), SYN (1.45-fold, p < 0.05), and PSD-95 (1.57-fold, p < 0.05). These findings establish a foundation for developing DHA nutritional supplements.