Lecture 13 March 2013
Making Vitamin D: You can make all the VIT D that your body needs.
UV light from the SUN converts (7 dehydrochoestrol(precursor in the skin) it helps
convert it into Previtamin D3.
Its carried into the blood. Foods from the foods (plant origin you can get ergocalcierfol or
animal you get cholecalciferol) ▯ALL is converted into Vitamain D3 (Calciol) [this
conversion however is not very good]
VIT D3 before it can be used by the body it has to be hydroxylated
(i) hydro laxation first one occurs in the liver ▯not functional yet needs to be further
(ii)another hydroxylation occurs in the kidney 1,25 didhyroxvitamin D3 > this one does
what VIT D does in our body…
This is why individual with kidney cannot metabolise Vit D3
When you check your VITAMIN STATUS they measure 25 hydroxyvitmain D3
The optimal serum concentration regarding to bone health, is 80 to 120 nmol/L or
3060ng/mL since VIT D is very important know these numbers**
Toxicity: > 375nmol ▯know this
ROLES OF VIT D
VIT D in BONE GROWTH
Regulation of bone growth, (very important)
It also manages blood calcium levels. Which tissue acts on for controlling blood calcium
levels?? (i) Intestines (ii) The kidney (iii) Bones
Intestine ▯Absorption of calcium from diets
Kidney ▯ reabsorption of calcium by body, so its not excreted in urine
Bone ▯ if there is no calcium coming from diet, and from kidney is not enough then VIT D
will activate OSTEOCLAST so calcium can be released.
VIT A, C, K(needed for making specific proteins that helps to retain minerals in the
bones) VIT D in OTHER ROLES
Brain & Nervous System
VIT D Factors that Lead to Deficiency
Breastfeeding without supplementation
Implication for Ca absorption: Calbindin ( transporter that is needed for taking from the
diet , if its not there you wont be able to absorb it)
THE WORLD SLIDE
People living in North of 40 or South of 40 don’t get as much exposure
Where you live and VIT D?
The more NORTH YOU go you wont be able to make VIT D
VIT D Deficiency: RICKETS (condition that is common among children)
People that live in northern climates will experience RICKETS more
Rickets (due to reduction in VIT D, and Red in Calcium level in the blood)
Rickets is a disorder caused by a lack of vitamin D, calcium, or phosphate. It
leads to softening and weakening of the bones.
Beaded ribs (beads around ribs)
Recommendation : 10microgram/day daily(child)
OSTEOMALACIA (common in ADULTS)
VIT D ▯ There is poor production and activation of VIT D in elderly Fatsoluble vit as a group can lead to toxicity
VIT D stands out the one, which will develop toxicity more quickly.
Hypercalcemia ▯High levels of calcium in blood & then the calcium is deposited in
abnormal places in kidney which can lead to kidney stones etc.
Blood vessels that supply the heart co