Vitamins Flashcards
Vitamin D functions
Intestine --Increases Ca++ uptake --Increases Phosphate and Mg2+ absorption Kidney --Stimulates PTH--> reabsorption of Ca++ Bone --Reabsorption of Ca++
Vitamin D deficiency
- -Rickets (children)
- -Osteomalacia (adults)
Vitamin D toxicity
- -Hypercalcemia
- -Sarcoidosis and excess supplementation are possible
Vitamin K functions
- -Post-translational modification of various clotting factors (proteins C and S, prothrombin, II, VII, IX, X
- -Synthesized by intestinal factors
Vitamin K deficiency causes
- -Warfarin
- -Anticonvulsants
- -Antibiotics
Vitamin A functions
–Used to treat acne, measles, AML (M3 subtype)
Vitamin A deficiency
- -Night blindness
- -Xerophthalmia
- -Keratomalacia
- -Bitot spots
Vitamin A toxicity
- -Headache
- -Nausea and vomiting
- -Increase in intracranial pressure
- -Dry and pruritic skin
- -Hepatomegaly
- -+/- cirrhosis
- -Bone and joint pain
- -Alopecia
- -TERATOGENIC
Vitamin E (Alpha-tocopherol) deficiency
- -Hemolytic anemia
- -Spinocerebellar degeneration (ataxia)
- -Peripheral neuropathy
- -Proximal muscle weakness
Vitamin C (ascorbic acid) function
- -Hydroxylation of proline and lysine residues of collagen
- -Required in conversion of dopamine –> NE
- -Antioxidant
- -Facilitates iron absorption in gut
Vitamin C deficiency
- -Anemia
- -Sore, spongy gums
- -Loose teeth
- -Fragile blood vessels
- -Hemarthrosis
- -Impaired wound healing
- -Swollen joints
Vitamin B1 (thiamine) functions
- -Active form: thiamine pyrophosphate
- –Cofactor with pyruvate dehydrogenase, alpha ketoglutarate dehydrogenase, transketolase
Vitamin B1 (thiamine) deficiency
- -Occurs with poor nutrition (alcoholism), malabsorption
- -Damage of medial thalamus and mamillary bodies of posterior hypothalamus
- -Wernicke-Korsakoff syndrome
- -Beriberi
Wet beriberi
- -Peripheral vasodilation
- -High output heart failure
- -Edema
- -Cardiomegaly
Dry beriberi
- -Peripheral neuropathy
- -Muscle weakness
- -Hyporeflexia or areflexia
Vitamin B2 (riboflavin) function
- -Active forms: flavin mononucleotide (FMN) or flavin adenine dinulcleotide (FAD)
- -Cofactors for redox reactions (if enzyme has dehydrogenase in name, likely requires riboflavin)
Vitamin B3 (niacin) function
- -Active forms: Nicotinamide adenine dinucleotide (NAD) and Nicotinamide adenine dinucleotide phosphate (NADP)
- -Important in redox reactions
- -Derived from tryptophan
- -Used in patients with dyslipidemia
Vitamin B3 (niacin) deficiency
- -Pellagra (dementia, diarrhea, dermatitis)
- -Can be caused by dietary deficiency, Hartnup disease, Malignant carcinoid syndrome, Isoniazid (inhibits B3 and B6)
Vitamin B5 (pantothenate) function
–Compound of coenzyme A
Vitamin B5 (pantothenate) deficiency
- -Dermatitis
- -Alopecia
- -Adrenal insufficiency
- -Enteritis
Vitamin B6 (pyridoxine) function
- -Active form: pyridoxal phosphate
- -Coenzyme for many enzymes especially involved in transaminations and deaminations
- -Conversion of amino acid precursors
Vitamin B6 (pyridoxine) deficiency
- -Angular cheilosis
- -Glossitis
- -Convulsions
- -Peripheral neuropathy
- -Hyperirritability
- -Isoniazid can cause deficiency
Vitamin B7 (Biotin) function
–Apoenzyme for carboxylation reactions (Enzymes with carboxylase in the name)
Vitamin B7 (Biotin) deficiency causes
- -Avidin in egg whites (uncooked) prevents absorption of biotin
- -Antibiotics
Vitamin B9 (folic acid) function
- -Synthesis and repair of DNA (purines and pyrimidines)
- -Rapid cell division and growth
- -Biologically active form is tetrahydrofolate
Vitamin B9 (folic acid) deficiency
- -Can be caused by medications or malnutrition
- -Can be low in pregnancy
- -Neural tube defects in utero
- -Growth failure
- -Megaloblastic anemia
- -Glossitis
- -Diarrhea
Vitamin B12 (cobalamin) function
- -Cofactor with homocysteine methyltransferase
- -Conversion of MMA to succinyl CoA
Vitamin B12 (cobalamin) deficiency
- -Megaloblastic anemia
- -Neuro symptoms: paresthesias, ataxia, memory loss, dementia, severe weakness
Vitamin B12 (cobalamin) sources
- -Only found in animal products
- -Supplements needed for strict vegans
- -Improper absorption most common cause of deficiency
