Plasmalogens in Alzheimer's Disease: A Narrative Review of Dietary Sources, Metabolism, and Neuroprotective Mechanisms.

Plasmalogens are ether phospholipids. They have a vinyl ether bond at sn-1 and polyunsaturated fatty acids at sn-2, and are abundant in marine- and animal-derived foods. Their unique structures may help maintain membrane organization, redox balance, and signaling. Human studies show that plasmalogen levels decline with age, and the drop is even sharper in Alzheimer's disease (AD), suggesting a link between dietary lipids and neurodegeneration. This narrative review summarizes dietary sources, molecular composition, and metabolism of plasmalogens, focusing on how structural diversity affects stability, bioavailability, and function. Based on cell and animal studies, we discuss potential mechanisms linking plasmalogens to AD pathology, including amyloid-β metabolism, oxidative stress, neuroinflammation, synaptic dysfunction, and myelin integrity. Unlike previous reviews, this work integrates structure-function relationships across food composition, lipid metabolism, and disease mechanisms. Finally, we discuss emerging uses in functional foods and precision nutrition, offering a fresh framework for dietary plasmalogens as part of neuroprotective strategies.