MIND Pattern Nutritional Intervention Modulates Mediterranean Diet Adherence and Gut Microbiota in Alzheimer’s Disease: An Observational Case–Control Study

<b>Background:</b> Evidence on non-restrictive MIND pattern interventions in Alzheimer's (ALZ) disease remains limited. <b>Methods:</b> In an observational case-control study, 60 participants (ALZ, n = 30; cognitively healthy controls, n = 30) completed baseline (T0) and follow-up (T1) after structured MIND counseling. Adherence was assessed via the MEDAS questionnaire. Stool samples (16S rRNA profiling) were taken and anthropometry and cognitive/functional measures were recorded at T0/T1. <b>Results:</b> In the ALZ group, MEDAS improved as adherence to the Mediterranean diet increased (increasing the use of vegetables ≥ 2/day, <i>p</i> < 0.01; and lowering butter adoption ≤ 1/day, <i>p</i> = 0.02), with a shift from low to moderate/high adherence; in controls, baseline Mediterranean diet adherence was already high, and changes in MEDAS categories were modest (low adherence from 13.8% to 3.6%, high adherence from 37.9% to 50.0%), with no statistically significant overall change (<i>p</i> = 0.39). Regarding gut microbiota (GM), in the ALZ group, alpha diversity increased significantly and Bray-Curtis PCoA separated T0 from T1. Species-level analysis showed increases in SCFA-linked taxa (e.g., <i>Anaerobutyricum hallii</i>, <i>Blautia luti</i>, <i>Eubacterium coprostanoligenes</i>) and reductions in dysbiosis/mucin-degrading taxa (e.g., <i>Mediterraneibacter torques</i>, <i>M. gnavus</i>, <i>Agathobacter rectalis</i>). Between-group Δ(T1 - T0) comparisons at the genus level indicated larger positive shifts in ALZ for <i>Anaerobutyricum</i>, <i>Oscillibacter</i>, <i>Faecalicatena</i>, <i>Romboutsia</i>, <i>Mediterraneibacter</i>, and <i>Blautia</i>, and more negative Δ for <i>Gemmiger</i>, <i>Subdoligranulum</i>, <i>Bifidobacterium</i>, <i>Clostridium</i>, and <i>Collinsella</i>. sPLS-DA showed partial separation (first two components ≈ 9% variance). <b>Conclusions:</b> A structured, non-restrictive MIND intervention was feasible, improved dietary adherence, and accompanied higher diversity and compositional remodeling of the GM in ALZ's disease. Larger randomized mechanistic studies are warranted.