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This Alzheimer's Risk Gene Rewires Your Brain Long Before Symptoms – and One Surprising Habit Could Blunt Its Impact

Scientists have identified that the APOE4 allele, which raises Alzheimer’s risk three‑ to four‑fold per copy, rewires hippocampal memory circuits in mice decades before any cognitive symptoms appear. Young APOE4 mice exhibit smaller, hyper‑excitable neurons, a pattern not seen in low‑risk APOE3 mice until old age. Blocking the overexpressed protein Nell2 restored normal neuron size and firing, suggesting the damage is not irreversible. Parallel human data from a Swedish cohort of 2,100 seniors showed that high meat consumption blunted the elevated dementia risk associated with APOE4, hinting at a modifiable lifestyle factor.