Nutrition Flashcards
What are the fat soluble vitamins?
- A, D, E, K
- Absorption dependent on gut (ileum) and pancreas
- Toxicity more common than for water-soluble vits
- Steatorrhea can cause fat-soluble vitamin deficiencies
What are the water soluble vitamins?
- B1 (thiamine: TPP)
- B2 (riboflavin: DAF, FMN)
- B3 (niacin: NAD+)
- B5: (pantothenic acid: CoA)
- B6: (pyridoxine: PLP)
- B7: (biotin)
- B9: (folate)
- B12 (cobalamin), stored in liver
- C: (ascorbic acid)
- B-complex deficiencies tend to result in dermatitis, glositis, & diarrhea
What are the functions of Vitamin A?
- Antioxidant, in visual pigments, in differentiation of epithelial cells, prevents squamous metplasia
- Used to treat measles and AML subtype
- Deficiency: night blindness, dry skin
- Excess: arthalgias (joint pain), headaches, skin changes, sore throat, alopecia, cleft palate,
What are the functions of Vitamin B1 (thiamine)?
-Cofactor for decarboxylation enzymes as TPP (PYRUVATE DEHYDROGENASE, a-ketoglutarate dehydrogenase, transketolase, branched-aa-dehydrogenase)
- Deficiency: polyneuropathy, impaired glucose breakdown, motor dysfunction, ATP depletion, brain and heart affected
- Wernicke-Korshakoff’s & Beriberi seen in alcoholics.
What is the function of Vitamin B2 (ribofavin)?
- Cofactor in oxidation and reduction (FADH2)
- FAD and FMN are derived from riboflavin
- FAD/FMN: part of pyruvate dehydrogenase
-Deficiency: Cheilosis (inflammation of lips), and Corneal vascularization , photophobia, stomatosis
What is the function of Vitamin B3 (niacin)?
- Constituent of NAD+ and NADP+
- Acts as electron acceptor
- Deficiency: glossitis (tongue inflammation), pellegra (dermatisitis, dementia, diarrhea)
- Excess: facial flushing
What is the function of Vitamin B5 (pantothenate)?
- Essential component of CoA & FA synthase
- Deficiency: dermatitis, enteritis, alopecia, adrenal insufficiency
What is the function of Vitamin B6 (pyridoxine)?
- Coverted to pyridoxal phosphate
- Cofactor in transaminations, decarboxylations, glycogen phosphorylase, & synthesis of heme/niacin/histamine/serotonin/NE/Epi/GABA
-Deficiency: convulsions, hyperirritability, neuropathy, anemias, insomnia, diarrhea, skin irrritation
What is the function of Vitamin B7 (biotin)?
- Cofactor for carboxylation enzymes (PYRUVATE CARBOXYLASE, Acetyl-CoA carboxylase, propionyl-CoA carboxylase)
- AcetylCoA —> MalonylCoA
- Deficiency (rare, by antibiotics or raw eggs): dermatitis, alopecia, enteritis
What is the function of Vitamin B9 (folic acid)?
- Converted to THF, ac oenzyme for 1-C transfer/methylation reactions
- Important for the synthesis of nitrogenous bases
-Deficiency (most common): Macrocytic, megaloblastic anemia, no neurological symptoms, but can cause neural tube defects in fetus
What is the function of Vitamin B12 (cobalamin)?
- Cofactor for homocysteine methyltransferase
- Regeneration of methionine and SAM
- Large reserve pool in the liver, so malabsorption is the most common cause for a deficiency
-Deficiency: macrocytic, megalobalstic anemia, hypersegmented neutrophils, neurological symptoms due to abnormal myelin.
What is the function of Vitamin C?
-Antioxidant, facilitates iron absorption, in collegen synthesis for hydroxylation of proline and lysine, cofactor of dopamine-B-hydroxylase to make NE
- Deficiency: scurvy (swollen gums, bruising, hemarthrosis, anemia, poor wound healing)
- Excess: nausea, vomiting, diarrhea, fatigue, risk of iron toxicity, sleep problems
What is the function of Vitamin E?
- Antioxidant, protects RBCs and membranes
- Deficiency: hemolytic anemia, muscle weakness, & demyelination in spinocerebellar tract
What is the function of Vitamin K?
- Catalyzes carboxylation of glutamic acid on various clotting proteins (factors II, VII, IX, X)
- Synthesized by intestinal flora, and deficiency may arise after prolonged use of antibiotics
-Deficiency: Neonatal hemorrhage. In adults, due to coumadin therapy to prevent thrombosis.
What is the function of Zinc?
- Essential for 100+ enzymes
- Deficiency: delayed wound healing, hypogonadism, anosmia & dysgeusia (distorted ability to smell and taste), decreased adult hair
How is ethanol metabolized?
- Ethanol is converted to acetaldehyde by alcohol dehydrogenase (in cytosol, w/NAD+)
- Acetaldehyde is converted to acetate by acetaldehyde dehydrogenase (in mitochondria w/NAD+)
- Zero order kinetics, NAD+ is the limiting reagent
What is ethanol hypoglycemia?
- Ethanol metabolism increased the NADH/NAD+ ratio in liver
- This causes diversion of pyruvate to lactate and OAA to malate, which inhibits gluconeogeneis and TCA cycle
- -> leads to hypoglycemia, hepatic fatty change, acidosis, and ketone production
Which metabolic pathways take place in both the mitochondria and the cytoplasm?
Heme synthesis
Urea cycle
Gluconeogenesis
What are kinases and phosphorylases?
- Kinase: uses ATP to add high-E P group
- Phosphorylase: adds Pi w/o using ATP
What are the four results of Kwashiarkor?
Malnutrition, Edema, Anemia, fatty Liver
What is Vitamin D’s function?
- Increased intestinal absorption of calcium and phosphate, increase bone mineralization
- Deficiency: Rickets, osteomalacia, hypocalcemic tetany
- Excess: hypercalcemia, hypercalciuria, loss of appetite, stupor, occurs in sarcoidosis (abnormal collections of chronic inflammatory cells in multiple organs)
Where do we find vitamin C?
Only in fresh fruits and vegetables
Where do we obtain niacin (vitamin B3) from?
- Synthesized from tryptophan, with VitB6 andB2
- Through diet: liver, poultry, and eggs
What foods do we get folic acid (vitamin B9) from?
-milk, uncooked fruits, vegetables
