Water Soluble Vitamins

Question 1

Dry Beriberi

Answer 1

Peripheral neuropathy + impairment of sensory, motor, and reflex functions; affects distal > proximal limbs

Myalgias - esp. lower extremities
Weakness and atrophy

Question 2

Wet Beriberi

Answer 2

Edema and high output cardiac failure - tachycardia, cardiomegaly, and CHF

+ sign/symptoms of Dry Beriberi

Question 3

Wernicke-Korsakoff

Answer 3

Classic triad: Confusion + opthalmoplegia + ataxia

Neuro signs are only partially reversible

Alcoholics are particularly at risk; also seen in re-feeding syndrome

Question 4

Thiamine - Function & Sources

Answer 4

Necessary for intermediate metabolism in all cells - glycolysis, TCA cycle, amino acid metabolism, nerve conduction

Sources: Whole grain, pork, legumes

Question 5

Riboflavin - Function and Sources

Answer 5

Co-enzyme for FAD and FMN necessary for redox reactions of the TCA cycle and oxidative phosphorylation; also amino acid and fatty acid metabolism

Sources: Dairy, liver, wheat germ, meat & poultry

Question 6

Riboflavin deficiency

Answer 6

Oral-ocular-genital syndrome

Cheilosis - cracking of lips; angular stomatitis - sores at the corners of the mouth

Increased vascularization of conjunctiva; photophobia

Scrotal dermatitis

Question 7

Niacin Function and Sources

Answer 7

Component of NAD and NADPH necessary for glycolysis, TCA cycle, oxidative phosphorylation, fatty acid synthesis/oxidation

Sources: Meat, poultry, fish, peanut butter, legumes
Pre-cursors: Tryptophan (from milk, eggs)

Question 8

Niacin deficiency

Answer 8

Pellagra - 4 Ds

Dermatitis
Dementia
Diarrhea
Death

Question 9

Folic Acid - Function & Sources

Answer 9

Single carbon transfers in nucleic acid synthesis, amino acid metabolism, and DNA methylation (epigenetics)

Sources: “foliage” - deep green vegetables, orange juice, fortified grains

Question 10

Folic Acid Recommendations for Pregnant Women

Answer 10

Women of child bearing age advised to have intake of 400 ug/day to prevent NTDs (neural tube closes by 4-6 wks gestation, before most women know they’re pregnant)

Pregnant women advised to have intake of 600 ug/day

Question 11

Folic Acid Deficiency

Answer 11

Macrocytic anemia
Hypersegmented neutrophils (> 6 lobes)
Elevated plasma homocysteine
Neural tube defects

Question 12

Vitamin B12 - Functions and Sources

Answer 12

Necessary for re-formation of tetrahydrofolate from methylfolate (methionine synthesis from homocysteine)

Required for catabolism of odd chain fatty acids

Sources: ONLY animal products (meat, milk, eggs)

Question 13

Vitamin B12 Absorption & Metabolism

Answer 13

Requires intrinsic factor from stomach; absorption occurs in terminal ileum; transport through circulation occurs via transcobalamin II

Stored in liver

Excreted via bile

Question 14

Vitamin B12 Deficiency

Answer 14

Macrocytic anemia
Hypersegmented neutrophils (> 6 lobes) 

Neurologic disturbances - paresthesias, gait disturbances, depression, dizziness; may be permanent

*Hematological effects indistinguishable from folate deficiency

Question 15

Vitamin B12 Deficiency - Risk

Answer 15

Inadequate IF secretion or antibodies to IF
Gastrectomy
Ileal resection
Breastfed infant of B12 deficient mother

Question 16

Ascorbic Acid - Functions

Answer 16

Antioxidant / reducing agent; improves absorption of iron via reduction of Fe3+ to Fe2+

Co-substrate in hydroxylation of proline and lysine in collagen synthesis, and of tryptophan in serotonin synthesis

Conversion of dopamine to norepinephrine

Sources: Fruits (citrus), broccoli, green peppers, potatoes

Question 17

Vitamin C - Absorption & Storage

Answer 17

Absorption is saturable, so percent absorption through GI tract decreases as intake increases; renal excretion limits plasma levels

Pool sizes of 1,500 mg maintained with intake at levels of RDA (75-90 mg/day); prevents scurvy x 30-45 days with no intake

Question 18

Ascorbic Acid Deficiency

Answer 18

Scurvy - associated with pool sizes < 300 mg

Hemorrhagic signs due to defective collagen formation in capillary basement membranes - bleeding gums, bruising, ecchymoses, petichiae; may cause anemia

Hyperkeratosis of hair follicules

Joint/bone pain