Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

HUNT241 > Nutrition Lecture 6: Vitamin D > Flashcards

Nutrition Lecture 6: Vitamin D Flashcards

1
Q

What is the main source of Vitamin D?

A

The sun!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some food sources of Vitamin D?

A

Cod liver oil, Sardines, Smoked salmon, Eel/tuna, some dairy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is essential to make vitamin D?

A

Cholesterol is essential to make vitamin D, but we still need to be careful about having too much

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What type of reaction is the action of creating Vitamin D from sunlight on the skin?

A

Non-enzymatic reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the precursor for Vitamin D?

A

7-dehydrocholesterol forms vitamin D3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the three different types of sunlight radiation?

A

UVC, UVB, UVA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is UVC?

A

The shortest wavelength, absorbed by the atmospheric ozone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is UVB?

A

Has the largest effect on the top layer of skin, causes redness/burning, SKIN CANCER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is UVA?

A

The longest wavelength, reaches deep into the layers of skin, causes aging/wrinkling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Most sunlight that gets through is….

A

UVA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What radiation is of most use and most concern?

A

UVB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What behavioural factors affect Vit D status?

A

Clothing, sunscreen, time of day, time spent outdoors, supplements, diet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does global dietary Vitamin D uptake?

A

The mandatory food fortification countries have good vitamin D intake levels (Canada, USA) - Most other countries are not over AI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are host-related factors that affect Vit D status?

A

Skin colour, age, sex, BMI, genetic differences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is melanin?

A

Melanin is a natural pigment responsible for the coloration of skin, hair, eyes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where is global skin colours the darkest?

A

In countries closest to the equator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Melanin is a natural protection of what?

A

The harmful effects of UV light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is one of the negative effects of melanin?

A

Have to spend more time in the sun to get sufficient Vit D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are environmental factors that affect Vit D status?

A

Season, latitude, altitude, clouds, pollution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does latitude affect vitamin D?

A

As latitude increases (moving towards the poles), the angle of the sun’s rays becomes more oblique, and the intensity of UVB radiation decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the two major forms of Vitamin D?

A

D2 and D3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where do we get D2 from?

A

Plant foods and fungi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where do we get D3 from?

A

Animal foods

24
Q

What does D2 start out as?

A

Ergosterol

25
How does ergosterol become D2?
- Starts out as ergosterol - Beta ring is broken down by UVB light - This forms Pre D2, with a broken ring - Then with the addition of heat it dorms vitamin D2
26
What does D3 start out as?
7-dehydrocholesterol
27
How does 7-dehydrocholesterol become D3?
- Beta ring is broken by UVB light - This forms Pre D3, with a broken ring - Then with the addition of heat it forms Vitamin D3
28
What is the main differences in structure between D2 and D3?
Extra double bond and methyl group on D2
29
Why is D3 more effective than D2?
D2 has lower affinity for the Vitamin D binding protein, therefore is cleared faster from circulation
30
Both D2 and D3 are transported in the blood via what?
Vitamin D Binding Protein (DBP)
31
What type of vitamin is Vitamin D?
Fat-soluble
32
What does vitamin D require to be absorbed?
Fat
33
Where is vitamin D absorbed?
In the upper small intestine
34
How is vitamin D absorbed in the small intestine?
By non-saturable passive diffusion
35
How is Vitamin D transported from the intestine to the liver?
by vitamin D binding globulin
36
What facilitates the absorption of vitamin D?
Mixed micelles
37
How do mixed micelles facilitate the absorption of vitamin D?
by solubilizing it in the watery environment of the small intestine, allowing for efficient uptake by intestinal cells.
38
Where is vitamin D soluble?
In the hydrophobic core of mixed micelles
39
Is vitamin D from food or skin biologically active?
NO - requires metabolic activation in the body
40
How is vitamin D made biologically active?
Either forms (D3, D2) Needs to be transported to the liver and then the kidney
41
What happens when Vitamin D3/D2 is transported to the liver?
D3/D2 is converted into 25(OH)D = calcidiol
42
What is the name for 25(OH)D?
Calcidiol
43
What is the biomarker of vitamin D status?
Calcidiol
44
Is calcidiol the active form?
No, needs to be transported from the liver to the kidneys to be activated
45
What happens when Calcidiol is transported to the kidneys?
Calcidiol is converted into 1,25(OH)2D = Calcitriol
46
What is the name for 1,25(OH)2D?
Calcitriol
47
Is calcitriol the active form?
Yes!
48
What is the vitamin D status of NZ adults?
68% = Sufficient 27% = Insufficient 5% = Deficient
49
What is vitamin D status by season?
- Great levels in summer - Decreases as winter comes closer - Parts of spring still low but starting to improve
50
What is vitamin D status by ethnicity?
Maori and pacific: - Less likely to get sunburnt - Less likely to be forming Vitamin D
51
What is vitamin D status by age and sex?
Women are lower than men Males tend to stay the same or get higher with age Women tend to get lower with age
52
What is vitamin D status by region? (North vs South)
Northern region has the lowest prevalence of vitamin D deficiency
53
What are rickets?
inadequate mineralization of growing bones in children, resulting in soft, weak bones and skeletal deformities
54
What is osteomalacia?
softening of the bones due to impaired mineralization of the bone matrix in adults
55
What is osteoid?
The bone protein matrix (primarily collagen)
56
Does excessive sun exposure cause vitamin D toxicity?
No, sustained heat on skin degrades pre-vitmain D3 and D2

HUNT241 (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions