Vitamin D (Calciferol, Calcitriol)

00:00 Then we move on to our final fat soluble vitamin.

00:05 Vitamin D, calciferol or calcitriol.

00:10 Vitamin D has a number of different forms.

00:13 The vitamin that we take as a supplement will generally be in the D3 form.

00:19 And it is involved in metabolic pathways that involve increase in calcium absorption and stimulating osteoblasts.

00:29 So that they deposit calcium into the bones.

00:33 So here we can see the pathway that the biggest key here I can say is, it relies on the sun to take a cholesterol and turn it into vitamin D3.

00:45 So the sun is ultimately our best source of vitamin D3.

00:50 You can see that's along the way there are various conversions to make D3 into it's active form that we can use which is the calcitriol.

01:00 And that is use in all the different processes that we have discussed.

01:05 Also I want to bring to light and as it's with the sun, the same cholesterol molecule in D3 pathway leads to the manufacture of many of our steroid hormones.

01:17 So stay in the sun.

01:20 So what's sorts of things can lead to a vitamin D deficiency.

01:25 Well, the first one that we may not jump to the conclusion of is breast milk and no sunshine.

01:32 Because unlike cows milk which we fortify, breast milk does not actually contain adequate vitamin D on it's own.

01:41 And so sun exposure is critical.

01:44 So make sure that your patient's children get plenty of sun along with the breast milk.

01:51 And the next thing that we can see from a deficiency is either in children or in adults.

01:58 Rickets is a symptom we don't see it much in the United States.

02:02 But results from a vitamin D deficiency.

02:05 Because we see less calcification of the bones.

02:08 On occasion we'll see that demineralization or loss of minerals from the bones in adults.

02:16 In which case we call it osteomalacia.

02:18 In the case of osteomalacia, it can result from vitamin D deficiency obviously.

02:26 But I've read some articles recently, about how a drug addiction and alcoholism can actually impact the absorption of vitamin D unless mineralization of the bones.

02:39 And literally the bones will become quite bendy.

02:41 And we can also see this deficiency evident in older adults.

02:48 Because if there's less vitamin D then there is less minerlization.

02:54 And thus we have much more likelihood of damage to the bones and fractures and such.

03:00 So on that note, here's a quick summary of all of our fat soluble vitamins.

03:08 Recall that visual and take a moment before you move on to another lecture to write down everything that you remember about the naked fat soluble vitamins.

03:21 And I look forward to seeing you in the next lecture.