| Effects of Deficiency | Vitamin | Toxicity of Overdose |
| scurvy; weak capillaries and venules causing diffuse ecchymoses and hemorrhaging; loosened teeth, glossitis, poor wound healing | |
| sideroblastic anemia, convulsions, peripheral neuropathy | |
| corneal neovascularization, glossitis, cheilosis, angular stomatitis | |
| megaloblastic anemia, neurologic disease, glossitis | |
| hemorrhagic disease of the newborn; GI bleeding and ecchymoses in adults | |
| pathologic fractures, excess osteoid, bow legs, tetany; rickets in children, osteomalacia in adults | |
| impaired night vision, blindness; follicular hyperkeratosis, pneumonia, growth retardation, renal calculi | |
| dry beri beri (peripheral neuropathy), wet beri beri (cardiomyopathy), Wenicke/Korsakoff syndrome | |
| pellagra (diarrhea, dermatitis, dementia) | |
| megaloblastic anemia, NO neurologic disease, glossitis | |
| dermatitis, alopecia, lactic acidosis | |
| hemolytic anemia, peripheral neuropathy, degeneration of posterior column and spinocerebellar tract | |
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