Nutrition

Question 1

Which are the water soluble vitamins?

Answer 1

All the B vitamins (1,2,3,4,5,6,7,9,12) and C

Before Christ there was only water, no wine

Question 2

What are the fat soluble vitamins?

Answer 2

A,D,E,K

Question 3

Vitamin A
Function
Deficiency
Excess
Where is it found

Answer 3

**Function: **Antioxidant, constituent of visual pigments (retinal), essential for normal differentiation of epithelial cells, prevent squamous metaplasia, treat measles and AML (subtype M3), Acne treatment

**Deficiency: **Night blindness (nyctalopia); dry, scaly skin (xerosis cutis); alopecia; corneal degenetration (keratomalacia); immune suppression

**Excess: **Arthralgia, skin changes (e.g. scaliness), alopecia, cerebral edema, pseudotumor cerebri, osteoporosis, hepatic abnormalitie
Teratogenic (negative pregnancy test required before prescription of isoretinoin for acne)

Question 4

Vitamin B1 - Thiamine
Function
Deficiency
Associated Dzs
Diagnostic criteria for def. dx

Answer 4

Function: TPP, cofactor for several DH reactions:
Pyruvate DH, Alpha-KG DH, Transketolase, Branched-chain ketoacid D

Deficiency: Impaired glucose breakdown resulting in ATP depletion, worsened by glucose infusion, highly aerobic tissues first affected

• *Diseases: Wernicke-Korsakoff** - Confusion, ophthalmoplegia, ataxia (classic triad); confabulation, personality change, memory loss (permanent) Damage to medial dorsal nucleus of thalamus, mamillary bodies
• *Dry Beriberi **- Polyneuritis, symmetrical muscle wasting
• *Wet Beriberi **- High-output cardiac failure (DCM), edema

**Diagnostics **- Increased in RBC transketolase activity post B1 administration

Question 5

Vitamin B2 - Riboflavin
Function
Deficiency

Answer 5

**Function: **Component of FAD and FMN, cofactors in redox reactions

Deficency: **Cheilosis (inflammation of lips, scaling and fissures at the corners of the mouth), Corneal vascularization (2 C’s of B2)

Question 6

Vitamin B3 - Niacin

Function
Deficiency
Excess

Answer 6

**Function: **Constituent of NAD,NADP; Derived from tryptophan. Synthesis requires vitamins B2 and B6. Used t otreat dysplipidemia (lowers VLDL, increases HDL)

Deficiency: **Glossitis leads to pellagra due to Hartnup disease (decreased tryptophan absorption), malignant carcinoid syndrome (increased tryptophan metabolism), isoniazid (decreased vitamin B6)
Pellagra symptoms: Diarrhea, Dementia, Dermatitis (3 D’s of B3)

**Excess: **Facial flushing (induced by prostaglandin, not histamine), hyperglycemia, hyperuricemia

Question 7

Vitamin B5 - Pantothenate
Function
Deficiency

Answer 7

**Function **- Essential component of coenzyme A (CoA, cofactor for acyl transfers), fatty acid synthase

**Deficiency **- Dermatitis, enteritis, alopecia, adrenal insufficiency

Question 8

Vitamin B6 Pyridoxine
Function
Deficiency

Answer 8

**Function **- Converted to pyridoxal phosphate, a cofactor used in transamination (ALT/AST), decarboxylation reactions, glycogen phosphorylase,. Synthesis of cystathionine, heme, niacin, histamine, NTs such as serotonin, epi, norepi, dopamine, GABA

**Deficiency **- Convulsions, hyperirritability, peripheral neuropathy, sideroblastic anemias due to impaired Hgb synthesis and iron excess

Question 9

Vitamin B7 Biotin
Function
Deficiency

Answer 9

**Function: **Cofactor for carboxylation reactions (addition of a 1C group)
Pyruvate carboxylase, Acetyl-CoA carboxylase, Propionyl-CoA carboxylase

**Deficiency: **Relatively rare. Dermatitis, alopecia, enteritis. Caused by antibiotic use or excessive ingestion of raw eggwhites

Question 10

Vitamin B9 - Folic Acid

Function
Deficiency and Labs During
Source

Answer 10

**Function: **Converted to THF for 1-carbon transfer/methylation reactions, important for synthesis of nitrogenous bases in DNA and RN

**Deficency: **Macrocytic, megaloblastic anemia; hypersegmented PMNs; glossitis; major issue in pregnant and alcholics
Labs: Increased homocystein, normal methylmalonic acid

**Source: **Leafy green vegetables absorbed in jejunum

Question 11

**Vitamin B12 **(Cobalamin)

Function
Deficiency and Labs
Source and Storage

Answer 11

**Function **- Cofactor for homocystein methyltransferase and methylmalonyl-CoA mutase

• *Deficiency - **Macrocytic, megaloblastic anemia; hypersegmented PMNs; parestheisa, and subacute combined degeneration (dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts) due to abnormal myelin. Prolonged deficiency results in irreversible nerve damage. Can be due to pernicious anemia, veganism, malabsorption (sprue, enteritis, Diphyllobothrium latum), other lack of IF or absence of terminal ileum (Crohn’s)
• *Labs : **Elevated serum homocystine and methylmalonic acid levels; Anti-IF Ab dx for pernicious anemia
• *Source: **Animal products, synthesized only by microorganisms
• *Storage: **Large reserve pools (several years) in liver

Question 12

Vitamin C (ascorbic acid)
Function
Deficiency
Excess
Source

Answer 12

**Function: **Antioxidant; Facilitates iron absorption by reducing it to a ferrous state; Necessary for hydroxylation of proline and lysine in collagen synthesis; Necessary for dopamine B-hydroxylase, which converts dopamine to NE

**Deficiency: **Scurvy (swollen gums, bruising, hemarthrosis, anemia, poor wound healing, perifollicular and subperiosteal hemorrhages, “corkscrew” hair); Weakened immune response

**Excess: **Nausea, vomiting, diarrhea, fatigue, calcium oxalate nephrolithiasis; Can increase risk of iron toxicity in predisposed individuals

**Source: **Fruits and vegetables

Question 13

Vitamin D
Types
Function
Deficiency
Excess

Answer 13

Types: D2 - Ergocalciferol; Ingested from plants
D3 - Cholecalciferol: Consumed in milk, formed in sun-exposed skin (stratum basale)
25-OH D3: Storage form
1,25-(OH)2 D3 (Calcitriol): Active form

**Function: **Intestinal absorption of calcium and phosphate, increases bone mineralization

**Deficiency: **Rickets in children (bone pain and deformity), osteomalacia in adults (bone pain and muscle weakness), hypocalcemic tetany. Breastfed infants should receive oral vitamin D. Exacerbated by low sun exposure, pigmented skin, prematurity

**Excess: **Hypercalcemia, hypercalciuria, loss of appetite, stupor. Seen in sarcoidosis (activation of vitamin D by epithelioid macrophages)

Question 14

Vitamin E - Tocopherol/tocotrienol
Function
Deficiency

Answer 14

**Function **- **Antioxidant (protects eryhtrocytes and membranes from free radical damage)

**Deficiency - **Hemolytic anemia, acanthyosis, muscle weakness, posterior column and spinocerebellar tract demyelination

Question 15

Vitamin K
Function
Deficiency
Source

Answer 15

**Function - **Cofactor for the gamma-carboxylation of glutamic acid residue on various proteins for blood clotting

**Deficiency **- Neonatal hemorrhage with increased PT and aPTT but normal bleeding times. Also occur after prolonged use of broad-spectrum antibiotics

**Source - **Intestinal flora, needs to be given via injection to neonates

Question 16

Zinc
Function
Deficiency

Answer 16

• *Function - **Essential for the activity of 100+ enzymes. Important in the formation of zinc fingers (transcription factor motif)
• *Deficiency **- **Delayed wound healing, hypogonadism, decreased post-puberty hair, dysgeusia, anosmia, acrodermatitis enteropathica. May predispose to alcoholic cirrhosis

Question 17

What is Kwashiokor?

Answer 17

Disease of protein malnutirtion resulting in skin lesions, edema, liver malfunction
Think MEAL: Malnutrition, Edema, Anemia, Liver (Fatty)

Question 18

What is Marasmus?

Answer 18

Total calorie malnutirition resulting in tissue and muscle wasting, loss of subcutaneous fat, and variable edema