Nutrition Flashcards
Water Soluble Vitamins that wash out easily?
All but B12 and folate which are stored in liver
B complex deficiencies result in
Dermatitis, Glossitis, Diarrhea
VitA General function Physiological role Developmental role Role in cancer Use as a medication Where is it found?
Antioxidant
Constituent of visual pigments (retinal)
Essential for normal differentiation of epithelial cells into specialized tissue (pancreatic cells, mucus-secreting cells)
Prevents squamous metaplasia
Used to treat measles, AML (subtype M3), wrinkles and acne
Found in liver and leafy vegetables
VitA
Deficiency
Excess
Night blindness and dry skin
Arthritis, Fatigue, Headache, Skin changes, Sore Throat, Alopecia, Teratogenic (cleft palate, cardiac abnormalities)
VitB1
Name
Enzymatic role
Thiamine
Part of Thiamine PyroPhosphate (TPP), a cofactor for decarboxylation reactions: “ATP Branch”
Pyruvate dehydrogenase (Glycolysis, TCA cycle), α-ketoglutarate dehydrogenase (TCA cycle), Transketolase (HMP shunt), Branched-chain AA dehydrogenase
VitB1 Deficiency PathoPhys What worsens it? Which tissues affected? Context Names
Impaired glucose breakdown –> ATP Depletion worsened by glucose infusion
Highly aerobic tissue (brain and heart) affected first
Malnutrition or Alcoholism
Wernicke-Korsakoff, Beriberi
Wernicke-Korsakoff
Deficiency
Region damaged
Presentation
VitB1
Confusion, Ophthalmoplegia, Ataxia + Confabulation, Personality changes, Memory loss
Damage to medial dorsal nucleus of Thalamus, Mammillary bodies
Dry Beriberi
Deficiency
Presentation
VitB1
Polyneuritis, Symmetrical muscle wasting
Wet Beriberi
Deficiency
Presentation
VitB1
High output cardiac failure (Dilated Cardiacmyopathy), Edema
VitB2
Name
Function
Deficiency
Riboflavin
Cofactor in oxidation and reduction (FADH2). FAD and FMN are derived from B2 and yield 2 ATPs
“2 Cs of B2”
Cheilosis and Corneal vascularization
VitB3 Name Function Derived from... Synthesis requires... Deficiency Excess Used as treatment for...
Niacin
Constituent of NAD+ and NADP+ used in RedOx reactions to produce 3 ATP (B3 –> 3 ATP)
Derived from Tryptophan
Synthesis requires VitB6 and VitB2
Glossitis, Pellagra
Facial flushing due to pharmacologic doses for treatment of hyperlipidemia
Pellagra
Causes
Presentation
Hartnup Disease (↓ Tryptophan absorption), Malignant Carcinoid Syndrome (↑ Tryptophan metabolism), INH (↓ VitB6), VitB3 deficiency Diarrhea, Dermatitis, Dementia
VitB5
Name
Function
Deficiency
Pantothenate “PENTOthenate”
Essential component for CoA and Fatty Acid Synthase
Dermatitis, Enteritis, Alopecia, Adrenal insufficiency
VitB6 Name What is it converted into? Kind of reactions it is involved with? What molecules does it help synthesized? Deficiency What can cause it?
Pyridoxine
Converted into Pyridoxal Phosphate
Cofactor for Transamination, Decarboxylation, Glycogen phosphorylase
Synthesizes Crystathionine, Heme, Niacin, Histamine, Neurotransmitters (5HT, Epi, NE, GABA)
Convulsions, Hyperirritability, Peripheral neuropathy, Sideroblastic Anemia (impaired hemoglobin synthesis and iron excess)
INH or oral contraceptives can lead to it?
VitB7 Name What kind of reactions Enzymes Deficiency What causes it?
Biotin
Cofactor for Carboxylation enzymes that add 1 carbon group
Pyruvate carboxylase, Acetyl-CoA carboxylase, Propionyl-CoA carboxylase
Rare, Dermatitis, alopecia, enteritis
Caused by antibiotics or ingestion of raw eggs
BitB9 Name What is it converted into? What kind of reactions? What does it synthesize Where is it found? Where is it stored in the body?
Folic Acid THF Coenzyme for 1 carbon transfer/methylation Nitrogenous bases in DNA and RNA Leafy vegetables Small reserve pool stored in liver
VitB9 deficiency What happens? Frequency What can cause it? When and why is it given as a treatment
Macrocytic, Megaloblastic anemia, No neurological symptoms (as opposed to B12)
Most common deficiency in US
Alcoholism, Pregnancy, Phenytoin, Sulfonamides, MTX
Given to prevent neural tube defects in early pregnancy
VitB12 Name Function Where is it found? What synthesizes it? Storage?
Cobalamin
Cofactor for homocysteine methyltransferase (transfers CH3 groups as methylcobalamin and methylmalonyl-CoA mutase)
Found in animal products
Synthesized by microorganisms
Very large reserve pool (several years) stored in liver
VitB12 Deficiency
Presentation
Etiology
Test
Macrocytic Megaloblastic anemia, Hypersegmented PMNs, Neurological symptoms (paresthesia) due to abnormal myelin. Prolonged deficiency leads to irreversible nervous system damage
Malabsorption (sprue, enteritis, Diphyllobothrium latum), Lack of IF (pernicious anemia, gastric bypass surgery), Absence of terminal ileum (Crohn’s disease)
Schilling test to detect etiology of the deficiency
VitB12 Reactions
Homocysteine + THF-CH3 –> [Homocysteine MethylTransferase w/ B12] –> Methionine + THF
Methionine gives CH3 for anabolic reactions
THF ->->-> dTMP pyrimidines
Odd # fatty acids –> Methylmalonyl-CoA –> [B12] –> Succinyl-CoA
VitB6 Reactions
Homocysteine ->->-> [B6] –> Cysteine
Succinyl-CoA –> [B6] –> Hb
Combined VitB12 and VitB6 Reactions
Odd # fatty acids –> Methylmalonyl-CoA –> [B12] –> Succinyl-CoA –> [B6] –> Hb
S-Adenosyl-Methionine What is it made of? What is its function Basic Reaction Regeneration requires What reaction in neurons requires it?
ATP + Methionine Transferes methyl units Methionine + ATP --> SAM --> CH3 (for anabolic pathways) + Homocysteine Regeneration requires B12 and Folate Required for conversation of NE to Epi
VitC
Name
Function
Where is it found?
Ascorbic Acid
Antioxidant, Facilitate iron absorption by keeping iron in reduced Fe2+ state
Necessary for hydroxylation of proline and lysine in collagen
Necessary for Dopamine-β-Hydroxylase to convert DA into NE
Found it fruits and Vegetables
VitC
Deficiency
Excess
Weakened immune response, Scurvy due to collagen synthesis defect (swollen gums, bruising, hemarthrosis, anemia, poor wound healing)
Nausea, Vomiting, Diarrhea, Fatigue, Sleep Problems, and Risk of Iron Toxicity in predisposed individuals (transfusions, hemochromatosis)
VitD
Names with Source
Storage form
Active form
D2 - Ergocalciferol - ingested from plants
D3 - Cholecalciferol - consumed in milk, sun exposure
25OH D3 is storage form
1,25, OH2 D3 is active form
VitD
Function
Deficiency
Excess
Intestinal absorption of Ca and PO4, Increased bone mineralization
Rickets in children, Osteomalacia in adults,
HypoCa tetany. Decreased VitD in dark skinned pts.
HyperCa, Hypercalcinuria, loss of appetite, stupor. Seen in Sarcoidosis
VitE
Function
Deficiency
“E is for Erythrocytes”
Antioxidant (protects erythrocytes and membranes from free radical damage)
Fragile erythrocytes leading to hemolytic anemia. Muscle weakness, posterior column and spinocerebellar tract demyelination
VitK Function What synthesizes it? What enzymes are VitK dependent? VitK antagonist Deficiency results in... What causes deficiency? When is it used as a medicine?
Catalyzes γ-carboxylation of glutamic acid residues on various proteins of blood clotting
Synthesized by intestinal flora
II, VII, IX, X, Proteins C and S
Warfarin –/ VitK
Neonatal hemorrhage with ↑ PT and ↑ aPTT but normal bleeding time
Infancy (because of sterile intestines) or broad spectrum antibiotics
Given to neonates because not in breast milk and prevents hemorrhage
Zinc
Function
Deficiency
Predisposes pts to…
Enzyme activity. Zn fingers in transcription factors
Delayed wound healing, Hypogonadism, ↓ adult hair, Dysgeusia, Anosmia
Predispose to Alcoholic Cirrhosis
Ethanol Hypoglycemia
- EtOH metabolism leads to ↑ NADH/NAD ratio in liver
- When NADH high, Pyruvate –> Lactate, Oxaloacetate –> malate
- This leads to inhibition of gluconeogenesis and stimulates Fatty Acid Synthesis
- Hypoglycemia and Hepatic Fatty Change
- Overproduction of lactate –> acidosis
- Depletion of oxaloacetate shuts down the TCA cycle, shunting acetyl-CoA into ketone production
- Excess malate ↑ NADPH and thus fatty acid synthesis
Names of malnutrition syndromes
Kwashiorkor and Marasmus
Kwashiorkor
Lack of what?
Presentation
Classic patient
Protein malnutrition
“MEAL” Malnutrition, Edema, Anemia, Liver
Skin lesions, edema, Liver malfunction (fatty change due to ↓ apolipoprotein synthesis)
Small child with a swollen belly
Marasums
What is it?
Presentation
Energy malnutrition
Tissue and muscle wasting, loss of subcutaneous fat, edema
EtOH Metabolism
Pathway
Limiting reagent
Kinetics
Cyto:
EtOH + NAD –> [Alcohol Dehydrogenase] –> Acetaldehyde + NADH
Mito:
Acetaldehyde NAD –> [Acetaldehyde Dehydrogenase] –> Acetate + NADH
NAD is limiting reagent
Zero-Order Kinetics
Fomepizole
MoA
Use
Inhibits Alcohol Dehydrogenase
Antidote for methanol or ethylene glycol poisoning
Disulfiram
MoA
Use
What does it produce
Inhibits Acetaldehyde Dehydrogenase
Alcoholism
Produces Hangover Symptoms
Only vitamins not in breast milk?
D and K
