Fat-soluble vitamins: ADEK — can accumulate and become toxic
Fat-Soluble Vitamins
Four vitamins stored in body fat — excess can reach toxic levels
A (retinol): vision and immune function. D (calciferol): calcium absorption, bone. E (tocopherol): antioxidant. K (phylloquinone): blood clotting. Stored in liver and adipose tissue.
A
Vision, immune function
D
Calcium absorption, bone health
E
Antioxidant
K
Blood clotting
Water-Soluble Vitamins
Water-soluble: B vitamins + C — excess is urinated out safely
Water-Soluble Vitamins
Eight B vitamins plus vitamin C — not stored, need regular intake
Without vitamin C, proline and lysine residues can't be hydroxylated → unstable collagen → bleeding gums, poor wound healing, bruising, joint pain. Killed sailors on long voyages before citrus was understood.
Vitamin D Deficiency
Vitamin D deficiency: rickets (children — bowed bones), osteomalacia (adults)
Vitamin D Deficiency
Vitamin D is needed for calcium absorption — deficiency weakens bones
Made in skin from UV-B sunlight. Deficiency: rickets in children (soft, bowing bones), osteomalacia in adults (soft bones, pain). Also linked to immune dysfunction and depression. Common in northern latitudes.
Folate and B12
Folate (B9): DNA synthesis and repair — deficiency causes neural tube defects and megaloblastic anemia
Folate and B12
Two B vitamins that work together — deficiency in either causes anemia
Folate: required for nucleotide synthesis (DNA building blocks). Deficiency in early pregnancy → neural tube defects. B12: required for myelin synthesis and folate metabolism. Deficiency: megaloblastic anemia, neurological damage.
Thiamine — Vitamin B1
B1 thiamine: energy metabolism cofactor. Deficiency = beriberi (peripheral neuropathy) or Wernicke's (alcoholics)
B2 riboflavin: component of FAD and FMN — electron carriers in ETC. Deficiency = ariboflavinosis (cracks at corners of mouth)
Riboflavin — Vitamin B2
The vitamin whose deficiency causes characteristic mouth sores
Riboflavin forms FAD (flavin adenine dinucleotide) and FMN (flavin mononucleotide) — electron carriers in the electron transport chain. Deficiency (ariboflavinosis): angular cheilitis (cracks at corners of mouth), glossitis (inflamed tongue), seborrheic dermatitis. Rare in isolation — usually with other B vitamin deficiencies.
Niacin — Vitamin B3
B3 niacin: component of NAD⁺ and NADP⁺. Deficiency = pellagra — 4 Ds: Diarrhea, Dermatitis, Dementia, Death
Niacin — Vitamin B3
The vitamin whose deficiency causes pellagra
Niacin forms NAD⁺ and NADP⁺ — critical electron carriers in metabolism. Pellagra: the 4 Ds — Diarrhea, Dermatitis (sun-sensitive rash on exposed skin), Dementia, Death. Historically common where corn was the dietary staple (niacin in corn is bound form). High-dose niacin: raises HDL, lowers triglycerides.
The vitamin that requires a specialized carrier for absorption
B12 requires intrinsic factor (from gastric parietal cells) for absorption in ileum. Pernicious anemia: autoimmune destruction of parietal cells → no intrinsic factor → B12 deficiency. Subacute combined degeneration of spinal cord: B12 deficiency damages posterior and lateral spinal columns. Vegans at risk — B12 only in animal products.
Vitamin A
Vitamin A (retinol): vision (rhodopsin), immune function, epithelial integrity. Deficiency = night blindness.
Vitamin A
Fat-soluble vitamin essential for vision and epithelial health
Retinal (from retinol): component of rhodopsin — visual pigment in rod cells. Retinoic acid: regulates gene expression, epithelial differentiation. Deficiency: night blindness (earliest sign), xerophthalmia (dry eyes), increased infection susceptibility. Toxicity: teratogenic in pregnancy (liver, isotretinoin).
Vitamin K
Vitamin K: essential for blood clotting factors II VII IX X. Warfarin works by blocking vitamin K recycling.
Vitamin K
The clotting vitamin — and the target of anticoagulant drugs
Vitamin K: cofactor for gamma-carboxylation of clotting factors II (prothrombin), VII, IX, X, and anticoagulant proteins C and S. K1 (phylloquinone): green leafy vegetables. K2 (menaquinone): bacteria, fermented foods. Warfarin: inhibits vitamin K epoxide reductase → can't recycle vitamin K → reduced clotting factor activity.
Essential Mineral Cofactors
Mineral cofactors: zinc (wound healing, immune, taste), iron (hemoglobin, ETC), iodine (thyroid hormones), calcium (bones, signaling)
Essential Mineral Cofactors
Four essential minerals and their key biochemical roles