Lec. 19 - Vitamins Flashcards
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)
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
What are 2 sources of Vitamin A?
- Animal sources
- Beta-carotene (orange pigment; precursor to vitamin A)
Name functions of vitamin A (3)?
- Retina/vision maintenance
- Teeth, skeletal, soft tissue development
- Growth and health of skin
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
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
What happens in children with vitamin A deficiencies?
Severe vit. A deficiency can lead to blindness (hyperkeratinization in the eye)
What is 1 solution to global vitamin A deficiency?
Golden rice (GMO rice with carotene added)
What is vitamin D
A prohormone
Name sources of vitamin D (3)
- Food sources
- Fortified cereals
- Sun
What is vitamin D vital for
Absorption of calcium, so healthy development of bones and teeth
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
Name the 2 biologically active metabolites of vitamin D
25-hydroxyvitamin D,
1,25-dihydroxy vitamin D
What CYP family is important for vitamin D synthesis
P450s
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)
What occurs in vitamin D deficiency (2)?
In children causes rickets, causing permanently bowed legs, and disrupted bones and joints
Higher susceptibility to osteoporosis
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
Name the classical vitamin D functions (3)
Calcium uptake
PTH downregulation
Osteoblast/osteoclast differentiation and function
Name non-classical vitamin D functions (4)
- Anti-hypertensive (blood pressure)
- Anti-bacterial
- Anti-cancer properties
- Anti-inflammatory
Name sources for vitamin E
nuts/greens/oil
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
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 cofactorDescribe 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)
- Enters stomach (protein bound)
- HCL in stomach causes dissociation
- B12 binds intrinsic factor
- Absorbed in ileum
- 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
