Vitamins Flashcards
Vitamin A
Functions
Vision-black and white; night vision
Cell differentiation
Vitamin A
Deficiency
Mild: night blindness
Severe:
-xerophthalmia (damage to cornea, dry eyes, scarring, blindness)
-hyperkeratosis (increased keratin synthesis)
-infection
Vitamin D
Functions
Calcium homeostasis
Gene expression and cell differentiation
Vitamin D
Source
- Synthesized from UV light
- Some dietary intake
- 2 forms
Vitamin D
Deficiency
- deficiency in childhood can lead to rickets
- deficiency in adulthood can lead to osteopenia and osteoporosis
- can cause hyperintense signal near ventricles (may lead to Alzheimer’s and dementia?)
Vitamin K
Functions
- blood clotting (needed to convert prothrombin to thrombin)
- bone calcification to make hydroxyapatite
Vitamin K
Deficiency
- uncontrollable bleeding
- give newborns vitamin K shot (because don’t yet have colonic bacteria needed to make vitamin K
Vitamin E
Function
Antioxidant
Sits in membranes and scavenges free radicals to prevent damage
Interacts with vitamin C…vitamin E transfers free radical to vitamin C which decreases the reactivity of it
Vitamin E deficiency
Hemolytic anemia-ruptured RBCs due to oxidative damage
Vitamin C
Functions
- antioxidant…needed for gutathione peroxidase in order to convert free radicals into water
- synthesis of molecules, especially collagen
- can reduce iron, copper, and chromium so it can be better absorbed (have to convert non-heme Fe3+ to Fe2+ in oder to absorb it)
Vitamin C
Deficiency
Scurvy (bleeding gums, poor wound healing, internal hemorrhaging)
“ATP” B-Vitamins
B1 (thiamin) B2 B3 B5 B7
B1 (thiamine)
Function
Thiamine ATP production (conversion of pyruvate to acetyl CoA); coenzyme TPP RNA/DNA synthesis NADPH synthesis Nerve function
B1 (thiamine)
Deficiency
Beri Beri:
- Dry: muscle wasting, leg cramps, neuropathy
- Wet: edema, heart enlargement
- Infantile: breast milk is thiamine deficient
- Cerebral=Wernicke-Korsakoff caused by alcoholism; involuntary movement and paralysis of eye
Heart failure with B1 levels at suboptimal status
B2 (riboflavin)
Functions
Riboflavin
Energy production (needed in Krebs); part of FAD and FMN
Synthesis of vitamins
NT metabolism
Shown to maybe reduce systolic and diastolic BP
B2 (riboflavin)
Deficiency
Rarely an isolated deficiency
Causes muscle weakness, cheilosis, stomatitis, glossitis
B3 (niacin)
Functions
Niacin
ATP production (glycolysis and Krebs) part of NAD and NADP Synthesis and metabolism of fatty acids, cholesterol, steroid hormones, DNA, vitamin C, folate
Decreases LDL and increases HDL, but side effects include flushing and itching
B3 (niacin)
Deficiency
Niacin
Pellegra: the 4 D’s (dermatitis, diarrhea, dementia, death)
B5 (panthenoic acid)
Function
Pantothenic Acid
Part of CoA
ATP production (glycolysis and Kreb’s)
Synthesis of heme, cholesterol, bile salts, phospholipids, fatty acids, steroid hormones)
B7 (biotin)
Function
Biotin
Gluconeogenesis
Protein Catabolism
Fatty acid synthesis
ATP production
B7 (biotin)
Deficiency
Uncommon, but could be caused by eating a lot of raw eggs (avidin), intestinal diseases
One Carbon Metabolism B-Vitamins
B6, 9, 12
Isoniazid
- drug used for tuberculosis treatment
- can cause B6 (pyridoxine) deficiency (and thus cause niacin deficiency)
B6 (pyroxidine)
Function
Pyroxidine
Part of coenzymes used in amino acid and fatty acid metabolism (transaminases, decarboxylases)
Needed for heme synthesis!
One-carbon metabolism (synthesis of cysteine is dependent on on B6 or else there will be a buildup of homocysteine)
B9
Function
Folate
Activates B12
Helps synthesize DNA for new cell growth, protects nerve cells
B6 deficiency (pyroxidine)
Pyroxidine
Microcytic, hypochromic anemia (can’t make heme without B6)
Convulsions (can’t make NTs)
Hyperhomocysteinemia-can’t breakdown homocysteine so risk of vascular disease increases.
B9 (folate)
Function
Folate
Synthesis of RNA and DNA through production of nucelotides (T, A, G)
Conversion of homocysteine to methionine
SAM synthesis in order to methylate (universal methyl donor)
B9 (folate)
Deficiency
Folate
Macrocytic/megaloblastic anemia (inhibited DNA synthesis)-large RBCs and increased number of lobes in PMNs (polymorphonucelear leukocytes)
Hyperhomocysteinemia because can’t metabolism homocysteine…increases risk of vascular disease and dementia
Neural tube defects (spina bifida and anencephaly)
Take folic acid supplement
B9 (folate)
Toxicity
May mask B12 deficiency
May cause cancer growth
B12 (cobalamine)
Function
Cobalamin
DNA and RNA synthesis by production of thymidine, adenine and guanine
Methionine recycling-conversion of homocystine to methionine
SAM synthesis
Odd-chain fatty acid metabolism
B12(cobalamine)
Deficiency and causes
Cobalamine
Macrocytic anemia (large RBCs and multilobed PMN)
Hyperhomocrysteinemia
Neurological disease (degeneration of spinal cord and brain, neuropathy)
Can be caused by dietary deficiency, pernicious anemia (can’t make IF so can’t absorb B12), and atrophic gastritis (can’t separate B12 from food so it can’t be absorbed)
Pernicious Anemia
Autoimmune disorder causing a loss of intrinsic factor in stomach
Causes B12 deficiency
Deficiencies in what vitamins cause microcytic anemia?
B6
Iron
Deficiencies in what vitamins cause microcytic anemia?
B9-folate
B12-cobalamine
Absorption of B12
Cobalamine
- Ingested and enters stomach with haptocorrin that is in the saliva
- In stomach, B12 separated from food; IF is released
- In duodenum, B12 is released from haptocorrin and binds to IF
- B12 and IF are absorbed by enterocyte in ileum
