Vitamin D

Question 1

What forms are there of vitamin D?

Answer 1

There are two forms:
- Vitamin D2 found in vegetables
- Vitamin D3 found in animals for example oily fish

Question 2

What is the best source of vitamin D?

Answer 2

Sunlight

Question 3

What happens to vitamin D after absorption?

Answer 3

After absorption, vitamin D undergoes hydroxylation in the liver, kidneys and immune cells to become the active form which maintains calcium balance in the body and regulates immune functions

Question 4

How does vitamin D promote immune regulation?

Answer 4

1. Binds to vitamin D receptor (VDR/RXR)
2. VDR/RXR travels to the nucleus and binds to VDRE and drives its transcription
3. This leads to reduced T cell proliferation, decreased th1 and th17 differentiation, increased Treg differentiation, inhibition of plasma cell differentiation and reduced antibody production

Question 5

What is the importance of vitamin D in acute inflammation>

Answer 5

• Reduces endothelial-neutrophil interactions
• Blocks pro-fibrotic effects of TGF-B on lung fibroblasts
• Can promote lung epithelial wound repair
• Inhibits NF-kB signalling
• Suppresses macrophage TLR expression

Question 6

Vitamin D deficiency

Answer 6

In the UK majority of population has vitamin D deficiency. Vitamin D deficiency is connected to many autoimmune diseases like MS or RA.