From APOE4-Dependent Glial Lipid Droplets to Genotype-Sensitive Intervention: Reappraising Palm-Derived Bioactives in Alzheimer’s Disease Through a Review

Alzheimer’s disease encompasses disturbances in lipid transport, membrane composition, lysosomal processing, and glial immunometabolism that are incompletely captured by amyloid-centred or generic antioxidant explanations. APOE ε4, a major genetic risk allele for late-onset Alzheimer’s disease, provides a mechanistic entry point because APOE4-associated glial lipid droplets may accompany inflammatory dysfunction and neuronal injury. This qualitative literature review critically integrates research published during 2020–2026 on APOE-dependent brain lipid homeostasis with studies of palm-derived tocotrienols, phytosterols, squalene, and fatty-acid fractions. Rather than equating lipid-droplet abundance with toxicity, the review differentiates adaptive lipid sequestration from persistent lipid-storage states linked to defective lipid trafficking, lipophagy, and cellular stress. Evidence is strongest for the pathological relevance of APOE4-sensitive glial lipid handling, more indirect for individual bioactive mechanisms, and presently inadequate for claims of APOE4-stratified cognitive benefit from palm-derived ingredients. Tocotrienols merit focused investigation for lipid-peroxidation and signalling effects; phytosterols require sterol-species and compartment-specific evaluation; squalene evidence remains preliminary; and saturated fatty-acid fractions warrant particular caution. An evidence-calibrated framework specifies genotype-isogenic human glial models, lipidomic and spatial readouts, pharmacokinetic exposure verification, glia–neuron functional endpoints, and staged translational decision rules. The review argues that the therapeutically meaningful target is restoration of lipid-processing competence rather than indiscriminate depletion of intracellular lipid droplets