Vitamin D Flashcards
T or F
You can get a vitamin D toxicity from sunlight and supplements
False, not from sunlight
For most of the US essentially no vitamin D can be produced in the skin from ____ through ____
November through February
Ergocalciferol is also known as ___
Cholecalciferol is also known as __
D2
D3
Mushrooms and yeast are examples of which type of vitamin D?
D2/ ergocalciferol
T or F
Sundried or UV exposed mushrooms would have much more Vitamin D compared to fresh mushrooms
True
Fatty fish is an example of vitamin D3 or D2?
D3/ cholocalciferol
T or F
When looking at supplements, the ones with vitamin D3 are better than D2
True
Cholesterol is converted to ______ by the skins ____ glands. The glands secret it onto the skins surface where it becomes incorporated into the ____ layer of the skin
7-dehydrocholesterol
Sebaceous glands
Epidermis
Ultraviolet B from sunlight converts 7-dehydrocholesterol into _____ which will become cholecalciferol via _____. The photo products of this process are lumisterol and ____
Previtamin D3
Thermal isomerization
Tachysterol
Factors affecting vitamin D synthesis are time of year, clothes, ____, ____, ____, weight, time of day, ____, ____, ____, and sunblock
Age
Cloud cover
Pollution
Solar moon best
UVA/ UVB ratio
Skin color
Vitamin D production does not occur before ___ and ceases after ____ even in summer
9 am
4 pm
African Americans often need __-__ times longer sun exposure compared to caucasians to make the same amount of vitamin D
5-10
MED stands for what? What does it measure
Minimal erythema dose
Measures how much vitamin D we make
___ can be defined as the amount of time needed to cause skin to turn pink
MED
What is the RDA for vitamin D?
15 ug
1 ug= __ IU
40
T or F
Vitamin D is high in breast milk so no supplementation is needed
False, 400 IU supplement needed
What are natural sources of vitamin D?
Cod liver oil
Shiitake mushrooms
Egg yolk
Fatty fish/their oil (tuna, salmon, sardines
What makes fish have different amounts of Vit D?
Amount of zooplankton available in diet
What are fortified sources of Vitamin D? Which is not a very good source?
Cows milk
Cheese (not good source)
Yogurt
Orange juice
T or F
Vitamin D in foods is fairly stable and not prone to cooking, storage, or processing losses
True
What is the best source of vitamin D?
The sun
T or F
Dietary Vitamin D2 and D3 requires no digestion
True
Where is most vitamin D absorbed?
Small intestine
How is the majority of vitamin D transported?
85% to Vit D binding protein (VDBP)
15% to albumin
T or F
Vitamin D2 and D3 are activated upon coming into the body
False, need to be activated no matter the source they come from
What are the main organs responsible for vitamin D activation?
Liver
Kidneys
What hormones regulate the metabolism of vitamin D activation?
Parathyroid hormone
Fibroblast growth factor 23 (FGD23)
Where does vitamin D2/3 go after being ingested or from the sun? What is it converted to?
Liver
Calcidiol
____ is the major circulating form of vitamin D
25(OH)D (calcidiol)
Do you measure vitamin D status using the diol or triol form?
Diol
____ is transported to the kidneys where it is converted to its active form ____
Calcidiol
Calcitriol
Where can activation of cacitriol occur?
Skin
Monocytes/macrophages
Adipose tissue
Skeletal muscle
Heart
Brain
Pancreas
T or F
The activation of calciotriol primarily takes place in the kidneys
True
T or F
Vitamin D can help lower blood pressure
True
What are vitamin D’s nongenomic functions?
Signal transduction pathways/
Intercellular signaling
What are the genomic functions of vitamin D?
Regulate gene expression/ transcription factor
Regulate cell growth, differentiation
Inhibition of unregulated proliferation
Immune system
Helps regulate BP
T or F
Vitamin D may help with cancer cells not spreading
True
Some more genomic functions of vitamin D are ___, decreasing ___, anti inflammatory, ____/strong bones, __ and __ regulation
Pancreatic B cells (help regulate insulin secretion)
Apoptosis
Skeletal growth
Ca and P regulation
If vitamin D is low, __-__% of dietary calcium is absorbed
10-15%
If vitamin D is adequate, __-__% of dietary calcium is absorbed
30-40%
T or F
If someone has a vitamin D deficiency, Ca absorption cannot be increased enough to satisfy bodies Ca needs
True
Vitamin D regulates calcium and ____ homeostasis. It (increases/decreases)____ Ca absorption in small intestine, (increases/decreases)___ res absorption to kidneys, and (increases/decreases) ____ mobilization of Ca from bone
Phosphorus
Increase
Increase
Increase
The synthesis of vitamin D requires:
A. UVA rays
B. Calcium up regulate cholesterol synthesis in skin
C. Tachysterol availability
D. Two correct
E. None correct
E
What is required to metabolize vitamin D in the body?
A. The liver
B. The kidneys
C. Circulating VDR2
D. Two correct
E. All correct
D
Which of the following is not a function of vitamin D that was mentioned in lecture?
A. Ca and P regulation
B. Insulin secretion
C. Immune system
D. Muscle synthesis
E. All were mentioned
D
Which of the following can lead to a low serum level of vitamin D?
A. IBD
B. High parathyroid hormone levels
C. Using sunblock with an SPF of 45
D. Two correct
E. All correct
D
Which of the following are directly involved in the absorption of vitamin D?
A. Micelles
B. Iodine
C. Zinc
D. Two correct
E. All correct
A
Parathyroid hormone is activated by:
A. Low serum calcium
B. Low or high bind mineral density
C. High vitamin D2 levels
D. Two correct
E. All correct
A
T or F
25-OH cholecalciferol and calcitriol are the same thing
False
The upper limit of vitamin D for someone who is pregnant is
A. 3000 IU
B. 75 mcg
C. 2500 IU
D. There is no upper limit established
E. None are correct
E
Which of the following are functions of vitamin D?
A. Increase calcium absorption in the large intestine
B. Increase calcium reabsorption in the kidney
C. Mobilize storage from small intestine and bone
D. Two correct
E. All correct
B
Which of the following are deficiencies of vitamin D that affects children?
A. Rickets
B. Osteoporosis
C. Cystic fibrosis
D. Two correct
E. All correct
A
600 IU of vitamin D equals ___ mcg
15
The mechanism of action for the active form of vitamin D is that it interacts with the nucleus of intestinal cells. Which of the following steps are correct?
A. Calcidiol bonds with VDR and enters the nucleus
B. The active form of vitamin D snd VDR binds to DNA along with RXR to form a complex which aids in DNA transcription
C. The ER produces a protein called Calbindin, calbindin will then aid in the absorption of Ca into the intestinal mucosal cell
D. Two correct
E. All correct
D
T or F
Vitamin D RDAs are based on obtaining a majority of vitamin form the sunlight
True
You need ___ for vitamin D to get absorbed into the intestinal cell it needs
Bile
What organ is typically responsible for the final activation of vitamin D in the body?
Kidneys
T or F
Some medications may interfere with vitamin D status
True
T or F
Many studies suggest that vitamin D2 increases serum 25[OH]D more efficiently than vitamin D3
False
Vitamin D can be broken down into ___ from sunlight exposure
A. Lumisterol
B. Dihydroxy vitamin D2
C. Campesterol
D. Two correct
E. All correct
A
T or F
Cholecalciferol can be synthesized from 7-dehydrocholesterol in the skin
True
Who would be more at risk for a vitamin D deficiency?
A. Someone with kidney failure
B. Someone with Chron’s disease
C. Someone with CVD
D. Two correct
E. All correct
D
T or F
Lumisterol is a form of vitamin D3
False
Which of the following affect the synthesis of vitamin D?
A. Weight
B. Age
C. Skin color
D. Two correct
E. All correct
E
