Lec. 19 - Vitamins Flashcards by David Vauthier

What are the 2 subcategories of vitamins?

What’s a distinguishing factor of the 2 groups?

Fat-soluble and water-soluble

Fat-soluble can be stored in body fat, whereas a continuous intake of water-soluble is necessary (due to their excretion)

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Name some consequences of vitamin deficiencies (7)

A -> night blindness
B1 -> Beriberi
B3 -> Pellagra
B12 & B9 (folic acid) -> Megaloblastic anemia 
C -> Scurvy
D -> Rickets and osteomalacia
K -> hemorrhage

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What are 2 sources of Vitamin A?

Animal sources

- Beta-carotene (orange pigment; precursor to vitamin A)

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Name functions of vitamin A (3)?

Retina/vision maintenance
Teeth, skeletal, soft tissue development
Growth and health of skin

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Describe process of light transduction in rod (4)

Rods contain disks which contain rhodopsin (retinal + opsin)
Light hits rhodopsin, retinal changes from cis -> trans
Trans retinal is straighter, detaches from opsin, activating Galpha activation
Galpha closes sodium channels, cell hyperpolarizes -> no more tonic inhibition of bipolar cell

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Describe some aspects of vitamin A deficiency (5)

Night blindness
Dry and scaly skin (hyperkeratinisation)
Abnormal epithelial cell function
Infertility (inadequate secretion from mucosal surfaces)
Impaired immune response

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What happens in children with vitamin A deficiencies?

Severe vit. A deficiency can lead to blindness (hyperkeratinization in the eye)

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What is 1 solution to global vitamin A deficiency?

Golden rice (GMO rice with carotene added)

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What is vitamin D

A prohormone

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Name sources of vitamin D (3)

Food sources
Fortified cereals
Sun

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What is vitamin D vital for

Absorption of calcium, so healthy development of bones and teeth

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How does light produce vitamin D?

UV reacts with enzyme in skin, making vitamin D precursor

Liver (hydroxyVitD) and kidney (dihydroxyVitD) convert precursor to vitamin D

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Name the 2 biologically active metabolites of vitamin D

25-hydroxyvitamin D,

1,25-dihydroxy vitamin D

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What CYP family is important for vitamin D synthesis

P450s

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Describe how vitamin D affects gene transcription

vitamin D binds vitamin D receptor
Vit D + receptor translocate to nucleus
Receptor heterodimerizes with RxR (retinoid X receptor)

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What occurs in vitamin D deficiency (2)?

In children causes rickets, causing permanently bowed legs, and disrupted bones and joints

Higher susceptibility to osteoporosis

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How were rickets cases dramatically reduced in Quebec?

Dr. Scriver proposed fortifying milk with Vitamin D, Steinberg (owner of Metro grocery store) mandated this to come in effect

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Name the classical vitamin D functions (3)

Calcium uptake
PTH downregulation
Osteoblast/osteoclast differentiation and function

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Name non-classical vitamin D functions (4)

Anti-hypertensive (blood pressure)
Anti-bacterial
Anti-cancer properties
Anti-inflammatory

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Name sources for vitamin E

nuts/greens/oil

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Vitamin E is a family of what sort of compounds?

What functions does it have?

Tocopherols, which are anti-oxidants/free radical scavengers

Anti-oxidant
Cardio health
CNS function

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Name 3 Vitamin E deficiency risks

-Hemolytic anemia:
red blood cells lysing, so not enough red blood cells present

Cardiovascular damage
CNS damage

What is a risk of Vitamin E overdose

Prostate cancer

Link between vitamin E and vaping?

Heating flavourants in vaping causes many compounds to be broken down, Vitamin E acetate one such metabolite contributing to lung disease

Name sources for vitamin K

plants/greens Intestinal bacteria can synthesize some as well

What is vitamin K necessary for

Synthesis of thrombins (coagulation of blood)

What drug can interfere with vitamin K synthesis? What are 2 of its uses

Warfarin. Anticoagulant Also a rat poison

What are the fat-soluble vitamins? And water-soluble vitamins (with names)?

Fat-soluble: D, E, A, K Water-soluble: C, B1, B2, B3, B5, B6, B7, B9, B12 ``` B1 -> thiamine B2 -> riboflavin B3 -> niacin B5 -> pantothenic acide B6 B7 -> biotin B9 -> folic acid/folate B12 ```

Where can vitamin C be found?

Fruits and vegetables (ex. citrus, broccoli, etc.)

Name some functions of vitamin C (4)

- Promotes healthy immune system - Enzyme activity (Electron donor in enzymatic reactions) - Synthesis of collagen (connective tissue) - Anti-oxidant

Describe vitamin C deficiency

Causes scurvy (easy bruising, anemia, gum bleeding, loss of teeth) Jacques Cartier shown pine needle tea treatment British physician 1700s discovered citrus could prevent scurvy

What is vit. B1 called?

Thiamine

What are sources for thiamine (B1) (4)

- Animal sources | - Fortified breads & cereals

Name 3 thiamine (B1) functions

- Metabolism (convert food to energy) - Cardiovascular system - Nervous systems

Describe thiamine (B1) deficiency

Beriberi -> Problems with cardiovascular, nervous system (encephalopathy) and metabolism 1880, Japanese physician solved beriberi in Japanese navy by adding milk and wheat to diet

What is vit. B2 called?

Riboflavin

What are sources for riboflavin (B2) (3)

- Cereals - Animal sources - veggies

Name 2 riboflavin (B2) functions

- Promote healthy growth | - Promote tissue repair

What is vit. B3 called?

Niacin

What are sources for niacin (B3)

-Animal products

Name a niacin (B3) functions

``` -Energy from metabolism ex. -Oxidative phosphorylation -Electron transfer -P450 cofactor ```

Describe niacin (B3) deficiency

``` Pellagra -> Sores all over Swollen tongue CNS deficiencies 3Ds -> diarrhea, dementia, Dermatitis ``` 1900s Southern American physician started adding niacin to flour to prevent pellagra in schoolchildren

What is vit. B5?

Pantothenic acid. Found in plenty of foods, deficiency is very rare

What are 3 sources for vit. B6?

- fish - meats - weats

Name 3 B6 functions

- Support cardiovascular system - Support CNS - Support immune system

What is vit. B9 called?

Folate/folic acid

What are the sources for folate/folic acid (vit. B9)?

- Leafy (foliage -> folate) | - Fortified grains/flour

Name 2 folate/folic acid (B9) functions

- DNA synthesis (several stages) | - Red blood cell production

Describe folate/folic acid (B9) deficiency

Megaloblastic anemia: Large, immature and non-functional red blood cells Spinal abnormalities in fetus

What are the sources for vitamin B12?

only animal products

Name 2 vitamin B12 functions

- CNS functioning (myelin formation) | - Red blood cell formation

How does vitamin B12 enter circulation? (4)

1. Enters stomach (protein bound) 2. HCL in stomach causes dissociation 3. B12 binds intrinsic factor 4. Absorbed in ileum 5. In epithelial cells of the intestine, dissociates from IF

Describe vitamin B12 deficiency

Can be caused by insufficient B12 intake OR insufficient intrinsic factor production Can cause: -Megaloblastic anemia: Large, immature and non-functional red blood cells -neuropathy