Exam #1: Vitamins II

Question 1

What are the two types of reactive species? What are reactive species?

Answer 1

Oxygen
Nitrogen

*****Highly reactive free radicals that are formed in the process of radiation, exposure to chemicals, & normal physiologic processes

Question 2

What are antioxidants?

Answer 2

Electron donors able to stabilize the free radical by “adding” an electron

Question 3

What are the three major antioxidant enzymes?

Answer 3

1) Superoxide dismutase
2) Glutathione peroxidase
3) Catalases

Question 4

What are the water soluble antioxidants?

Answer 4

• Vitamin C
• Urate
• Glutathione
• Bilirubin

Question 5

What are the lipid soluble antioxidants?

Answer 5

• Vitamin E
• B-Carotene
• A-Carotene
• Lycopene
• Lutein

Question 6

Can vitamins prevent atherosclerosis?

Answer 6

Yes, Vitamin E & C have been shown to slow the development of atherosclerosis

Question 7

Generally, which foods have higher antioxidant properties?

Answer 7

Red fruits and vegetables

Question 8

How do the antioxidant properties of foods compare to supplements?

Answer 8

Higher antioxidant defense in food (or other properties in food) vs. antioxidant supplement

Question 9

What is the relationship between AMD & antioxidants? What are the treatment implications?

Answer 9

AMD= Age Related Macular Degeneration

• Caused by oxidative stress
• Treatment with antioxidant supplementation slows progression

Question 10

Describe how fat soluble vitamins enter and are stored in the body.

Answer 10

1) Require bile salts/ emulsification for absorption
2) Carrier protein for transport
3) Stored in body fat (to some extent)

Question 11

What is the name for Vitamin A?

Answer 11

Retinol

Question 12

What is the name for Vitamin D?

Answer 12

Cholecalciferol

Question 13

What is the name for Vitamin E?

Answer 13

a-Tocopherol

Question 14

What is the function of Vitamin E?

Answer 14

Generally, Vitamin E is an antioxidant. Specifically it functions to:

• Maintain cell membrane integrity by preventing oxidation of unsaturated FAs
• Works closely with glutathione peroxidase

Question 15

What organs is Vitamin E especially important for?

Answer 15

• Lungs
• Brain
• Erythrocytes

Question 16

What are the negative interactions of Vitamin E with other fat soluble vitamins?

Answer 16

Vitamin K= antagonist (clotting factors)

Vitamin D= interfere with bone mineralization

Vitamin A= competition that may lead to deficiency

Question 17

What is the relationship between PUFAs and Vitamin E?

Answer 17

• Vitamin E stabilizes PUFAs

- Increased PUFA intake requires increased Vitamin E

Question 18

What are the causes of Vitamin E deficiency? What is Abetalipoproteinemia?

Answer 18

Abetalipoproteinemia= Rare genetic disease resulting in Vitamin E deficiency

Malabsoprtion syndromes e.g. celiac sprue and CF

Question 19

What are the manifestations of Vitamin E deficiency?

Answer 19

1) Hemolytic anemia
2) Retinal degeneration
3) Ceroid pigment accumulation
4) Neurologic deficits including damage to:
- Posterior columns
- Lateral corticospinal tracts
- Spinocerebellar tracts

Question 20

What are the signs of Vitamin E toxicity?

Answer 20

• Fatigue
• Diplopia
• GI distress
• Interference with other fat-soluble vitamins

Question 21

What are the major functions of Vitamin D?

Answer 21

1) Maintenance of adequate blood Ca++ and phosphorus
2) Cell differentiation
3) Immunity

Question 22

How is Vitamin D synthesized?

Answer 22

1) UV + 7-dehydrocholesterol forms D3
2) D3 from UV and dietary D3/D2 are transported to the liver
3) In the liver, Vitamin D is converted to 25-OH-D3, calcidiol*
4) This is transported to the kidneys, where it is further hydroxylated to 1, 25-OH D3 i.e. activated Calcitriol

*Measured in serum

Question 23

What is the active form of Vitamin D? What is the inactive form of Vitamin D? What is unique about the inactive form?

Answer 23

Active= Calcitriol 
Inactive= Calcitroic acid

*****Inactive= water soluble for excretion from the body

Question 24

What is the role of macrophages in Vitmain D synthesis? What is the role of Vitamin D in immunity?

Answer 24

Macrophages release Vitamin D, which then turns T/B cells on or off

Question 25

What are the major factors that influence Vitamin D synthesis?

Answer 25

- Time of day - Season - Latitude - Exposure to sunlight - Age - Skin pigmentation

Question 26

Above what latitude do individuals require Vitamin D supplementation in the winter months?

Answer 26

37 degrees i.e. us in Iowa

Question 27

What is the effect of low blood Ca++ on PTH and Vitamin D?

Answer 27

- PTH and Vitamin D3 are produced when blood Ca++ is low - PTH 1) stimulates Ca++ resorption from bone 2) enhances renal tubular reabsorption to INCREASE blood Ca++ 3) stimulates renal production of Vitamin D3 *****PTH induced increased in D3 leads to increased intestinal absorption of Ca++ and phosphorus

Question 28

What is the effect of Vitamin D supplementation on hip and nonvertebral fracture?

Answer 28

Supplementation prevented fracture

Question 29

What is the connection between autoimmune disease and Vitamin D?

Answer 29

Patients with autoimmune disease have low Vitamin D levels or receptor polymmorphisms

Question 30

What happens with Vitamin D toxicity?

Answer 30

1) Kidney stones 2) Metaststaic calcifications of the kidney/ hypercalcemia 3) Anorexia 4) Abdominal pain

Question 31

What do you need to keep in mind with Vitamin D supplementation?

Answer 31

D2 vs. D3

Question 32

What are the major functions of Vitamin A?

Answer 32

1) Constituent of visual pigments 2) Cell differentiation i.e. epithelial cell to specialized cell (transcription factor) 3) Antioxidant 4) Skin health

Question 33

What are the major symptoms of Vitamin A deficiency?

Answer 33

1) Night blindness 2) Dry skin Exacerbation of measles infection

Question 34

What is Vitamin A used as a therapy for? What form?

Answer 34

- Acne - Psoriasis - Leukemia *****Note that toxicity can happen with isotretinoin for acne*****

Question 35

What are the major manifestations of Vitamin A toxicity?

Answer 35

1) Alopecia 2) Visual changes 3) Headache 4) Skin changes 5) Hyperlipidemia 6) Hepatotoxicity 7) Arthralgia 8) Teratogen - Cleft palate - Cardiac abnormalities

Question 36

What are the three types of Vitamin K? Where do they come from?

Answer 36

1) Phylloquinone- Plants 2) Menaquinone- Animals & Bacteria 3) Menadione- Synthetic

Question 37

What are the functions of Vitamin K?

Answer 37

1) Carboxylation of glutamate, essential for production of blood clotting proteins - II, VII, IX, X and proteins S and C 2) Post-translational modification of proteins 3) Synthesis of bone, skeletal tissue and kidney Gla proteins

Question 38

What is unique about the synthesis of Vitamin K? Why is this important?

Answer 38

Vitamin K is synthesized to an active form by the gut flora 1) Antibiotics can deplete the normal gut flora leading to Vitamin K deficiency 2) Newborns are born with a lack of gut flora and are deficient in Vitamin K - Neonatal hemorrhage with increased PT and aPTT

Question 39

What are the symptoms of Vitamin K deficiency?

Answer 39

******Hemorrhage***** - Recall, neonatal hemorrhage with increased PT and aPTT

Question 40

What form of Vitamin K can be toxic?

Answer 40

- Synthetic, not natural *****Note that it combines with sulfhydryl groups cause oxidation of phospholipids

Question 41

What are the manifestations of Vitamin K toxicity?

Answer 41

1) Hemolytic anemia | 2) Hyperbilirubinemia

Question 42

What are the symptoms of Vitamin D deficiency?

Answer 42

1) Rickets in children - Bending bones - Rachitic bones 2) Osteomalacia 3) Tetany from hypocalcemia ******High risk in kids that are specifically breastfed*****