MODULE 1 Week 2: Vitamin A & Cartenoids

Question 1

Major functions of vitamin A

Answer 1

• Cell growth & reproduction
• Cell differentiation
• Bone development (osteoblasts/clast)
• Immune function
• VISION
• gene expression

Question 2

3 main forms of Vitamin A (retinoids)

Answer 2

1. Retinol
2. Retinal
3. Retinoic acid

Question 3

What are carotenoids? (Color?)

Answer 3

Red, orange, and yellow lipid-soluble pigments mainly found in plants

Question 4

**Beta-carotene exhibit is the XXX amount of pro vitamin A activity

Answer 4

Greatest

Question 5

Where is Vitamin A found in food?

Answer 5

LIVER, fatty fish (herring), dairy products, eggs

Question 6

** Most common dietary carotenoids/carotenoids most commonly found in the body? (6)

Answer 6

1. B-carotene
2. Alpha-carotene
3. B- crytoxanthin
4. Lycopene
5. Lutein
6. Zeaxanthin/Cryptoxanthin

Question 7

Are meat and fish major sources of carotenoids?

Answer 7

No

Question 8

What macronutrient improves vitamin A absorption? What percent is absorbed when this is present?

Answer 8

Need AT LEAST 10g of fat in a meal to absorb 70-90% of dietary vitamin A

Question 9

Does fiber (pectin) and vitamin E consumption improve or decrease Vitamin A absorption?

Answer 9

DECREASE (interferes with micelle formation)

Question 10

** Vitamin A/carotenoids are typically bound to what macronutrient in our diets?

Answer 10

PROTEINS

Question 11

** Vitamin A is typically esterfied to what ???

Answer 11

Fatty acids

Question 12

** What % of carotenoids are absorbed? Depends on what?

Answer 12

5-60%

Lower for UNCOOKED/JUICES and higher in FATTY MEAL/OIL BASED SUPPLEMENTS

Question 13

** Primary location where carotenoids (Alpha and beta-carotene & crytoxanthen) are converted to vitamin A

Answer 13

Intestinal mucosal cells

Question 14

** Retinoic acid v other forms of Vitamin A: how are they transported from intestines?

Answer 14

Retinoic acid = bound to ALBUMIN

Retinol/retinal/others = Added to CHYLOMICRON

Question 15

Primary location that chylomicrons deliver Vitamin A and carotenoids to?

Answer 15

Liver

Question 16

**Stellate cells

Answer 16

Specialized cells in liver where vitamin A is stored

Question 17

** Blood transport of Vitamin A depends on what 2 transport proteins (made by the liver)?

Answer 17

1. RBP (retinol-binding protein)

2. Transthyretin

Question 18

** 3 things required for optimal synthesis on RBP (retinol-binding protein)?

Answer 18

1. Adequate protein
2. Vitamin A
3. ZINC

Question 19

** Carotenoids are mainly delivered to what 2 locations?

Answer 19

1. Adipose tissues

2. Liver

Question 20

** The retina of the eye is especially high in what two carotenoids?

Answer 20

• Leutin

- Xeanthin

Question 21

**Vitamin A and osteoporosis

Answer 21

Up regulates osteoclasts (the cells that BREAK DOWN bone/calcium)

Question 22

*** Osteoporosis and up-regulated immune system

Answer 22

More WBC action (with unregulated immune system) means more osteoCLAST activity which means more bones are going to break down

Question 23

** Osteoporosis, inflammation, estrogen

Answer 23

Inflammation/up regulated immune system in addition to DECREASED estrogen could play a role in osteoporosis development

Question 24

** Vitamin A(retinol) palmitate is found in what foods?

Answer 24

• LIVER
• egg YOLKS
• Fish
• Dairy

Question 25

** Night-blindness due to deficiency in what vitamin?

Answer 25

A

Question 26

** Rhodopsin facilitates the conversion of light to X??

Answer 26

A neuroelectrical signal

Question 27

** Vitamin A and gene expression

Answer 27

* 2 forms of Retinoic acid interact with DNA response elements? Retinoic acid bins to certain receptors on DNA and influence transcription of certain proteins???????

Question 28

** Teratogenesis

Answer 28

Process by which congenital malformations are produced in a fetus

Question 29

** Vitamin A and birth defects (teratogenesis)

Answer 29

Toxic levels of vitamin A can lead to excessive growth and reproduction, leading to birth defects

Question 30

** Carotenoids as antioxidants are especially effective in lipid soluble compartments such as?

Answer 30

- Plasma membrane | - Lipoproteins

Question 31

** 2 main carotenoid antioxidant mechanisms of actions

Answer 31

1. QUENCHING (non-radical species) | 2. SCAVENGING (radical species = bad)

Question 32

** Who wouldn’t you recommend beta-carotene to? Why?

Answer 32

Wouldn’t recommend to smokers because of the associations with increased risk for lung cancer

Question 33

** Specific Vit A function with immune health

Answer 33

- Needed for T-lymphocyte function | - For antibody response to bacterial, virus, and parasitic infection

Question 34

** What parts of the eye are lutein and zeaxanthin found in?

Answer 34

Retina (specifically macula - central retina)

Question 35

** Function lutein and zeaxanthin in eye LOOK UP

Answer 35

- help QUENCH free radicals/effects of oxidation | -

Question 36

** If there is deficient/decreased vitamin A, what happens to iron incorporation into RBCs?

Answer 36

If vitamin A low, there is DECREASED iron incorporation into RBCs

Question 37

** Relationship between Vitamin A, iron, anemia

Answer 37

Low Vit A can lead to less iron incorporation into RBC. Supplementing with Vit A can help prevent/correct anemia

Question 38

** What tocopherol is Olive Oil high in?

Answer 38

Alpha

Question 39

** What is Xeropthalmia?

Answer 39

Abnormal dryness of the conjunctiva and cornea of the eye (due to Vit A deficiency)

Question 40

** What food (animal product) is high in vitamin a Palmitate?

Answer 40

Liver

Question 41

** What micro minerals affect vitamin A absorption and how?

Answer 41

ZINC deficiency - zinc deficiency reduces retinol binding protein capacity (therefore affecting vit A metabolism)

Question 42

** Main carotenoid colors

Answer 42

Red, orange, yellow

Question 43

Three carotenoids that are provitamins (can be converted to vitamin A)

Answer 43

1. Beta carotene 2. Alpha carotene 3. Beta cryptoxanthin

Question 44

** What B vitamin is needed for the formation of vitamin A (retinol) from beta carotene?

Answer 44

NIACIN

Question 45

** Which carotenoid has the strongest anti oxidant function?

Answer 45

Lycopene

Question 46

** Major components of carotenoid digestion & absorption (where does it happen?)

Answer 46

1. Freed from protein by PEPSIN in the stomach 2. Form fat globules 3. Emulsified by BILE in duodenum 4. Proteolytic enzymes hydrolyze 5. & Pancreatic lipas hydrolyze vitamin in small intestines 6. Form MICELLES 7. Travels through intestinal epithelial cells 8. Absorption occurs in duodenum and jejunum

Question 47

** Synthesis of vitamin A from Beta carotene requires what B vitamin and what mineral?

Answer 47

Niacin & IRON?

Question 48

** % / efficiency of beta carotene to retinol conversion

Answer 48

50%

Question 49

* 11-cis retinol v 9-cis Retinoic acid functions

Answer 49

11-cis = VISION 9-cis = GENE EXPRESSION

Question 50

** Where are carotenoids stored in the body? (Lutein and zeaxanthin?)

Answer 50

LIVER Less in adipose tissue Lutein and zeaxanthin = RETINA OF EYE

Question 51

** Form of vitamin A essential for vision

Answer 51

11-cis retinol

Question 52

** What is rhodopsin

Answer 52

Protein essential for vision formed from protein opsin + 11-cis retinol (Vit A)

Question 53

In visual cycle, 11-cis retiNOL is converted to what?

Answer 53

11-cis retinAL

Question 54

** Vitamin A and Accutane

Answer 54

Accutane in HIGH dose vitamin A; should not take Vit A supplements while on this medication

Question 55

** Accutane side effects

Answer 55

- dry skin - rash - nosebleeds - dry corners of mouth/eyes

Question 56

** Forms of vitamin A involved in gene expression

Answer 56

- trans retinoic acid | - 9 - cis retinoic acid

Question 57

** How does vitamin A play a role in gene expression

Answer 57

In the nucleus, Vit A interacts with nuclear receptors (bind to them) altering the activity of the cell/transcription