🧬 BDNF Extraction Viewer

Type 2 diabetes mellitus (T2DM) represents a systemic disease that extends beyond metabolic dysfunction to include accelerated neurocognitive decline driven by oxidative stress, inflammation, and insulin resistance. Emerging evidence suggests that essential micronutrients may interact synergistically or antagonistically with biguanides, particularly metformin, to influence neurocognitive function. This systematic review synthesized preclinical and clinical evidence on the interactions between essential micronutrients and biguanides (notably metformin) in modulating neurocognitive outcomes in T2DM. Following PRISMA 2020 guidelines, we systematically searched PubMed, Web of Science, and Scopus for studies published between 2010 and 2025. After screening 226 records in Rayyan, 40 studies met the inclusion criteria. Both preclinical and clinical studies were analyzed descriptively to identify patterns of mechanistic and functional outcomes. Extracted data covered intervention types, doses, duration, biomarkers, and cognitive outcomes. Of the 40 studies, 27 (67.5%) were preclinical and 13 (32.5%) were clinical, spanning 14 countries. Most interventions involved vitamin D, zinc, magnesium, vitamin E, or polyphenols, either alone or combined with metformin. Synergistic effects were observed in 77.5% of studies, with significant improvements in fasting plasma glucose, HbA1c, insulin sensitivity, and oxidative balance. Key molecular pathways involved AMPK, PI3K/Akt, GSK3β, and Nrf2-CREB, which mediated enhanced glucose utilization, mitochondrial function, and synaptic plasticity. Antagonistic effects (10%) were mainly linked to metformin-induced vitamin B12 depletion, which impaired neurotrophic signaling and elevated homocysteine levels. Across studies, neuroprotective benefits correlated with increased BDNF, PSD-95, and SIRT1 expression, and reduced IL-6, TNF-α, and MDA levels. Most (75%) of the studies showed a synergistic interaction between biguanides (metformin) and micronutrients save a few that showed antagonistic interaction. Integrating micronutrient supplementation particularly vitamin D, zinc, and antioxidant compounds into T2DM management enhances both metabolic control and cognitive function. These findings support a paradigm shift toward combined nutraceutical-pharmacologic therapy within clinical and public health frameworks. Future research should focus on dose optimization, mechanistic validation, and long-term clinical evaluation to develop evidence-based, nutrition-sensitive diabetes care models.