| Feature | Vitamin B12 (Cobalamin) Deficiency | Folate (Vitamin B9) Deficiency |
|---|
| Primary Unique Role | Neurological function (myelin sheath) | Neural tube development (in fetus) |
| Primary Sources | Animal products | Leafy greens, legumes, fortified foods |
| Body Stores | Large (Years) | Small (Months) |
| Absorption | Terminal Ileum (Requires Intrinsic Factor) | Duodenum/Jejunum (No Intrinsic Factor) |
| Key Unique Causes | Pernicious anemia, vegan diet, gastric surgery | Poor diet, alcoholism, pregnancy needs |
| Neurologic Symptoms | PRESENT (Paresthesias, gait issues, cognitive changes) | ABSENT |
| Key Lab Marker | Elevated Methylmalonic Acid (MMA) | Normal Methylmalonic Acid (MMA) |
| Treatment Danger | Folate alone masks anemia, allows neuro damage to progress | Less critical interaction (though diagnosis is key) |