Eupatilin and 8OHdG correlated with pTau217 and the pTau217/Aβ42 ratio, linking flavonoid signaling and oxidative DNA damage to tau phosphorylation.58 In parallel, 4-aminobenzoic acid positively correlated with both Aβ40 and pTau217, implicating folate-dependent one-carbon metabolism and MTHFR polymorphisms in disease risk.59-61 Nicotinamide correlated positively with the Aβ42/40 ratio, extending experimental evidence that NAD+ replenishment reduces amyloid burden and improves cognition.62-65 Diet- and microbiome-derived metabolites further shaped biomarker associations. This evidence concerns the gene MTHFR and amyloidosis.