Lesson on the role and importance of Vitamin D (calcitriol) in calcium absorption and why we actually need vitamin D for proper absorption and utilization of calcium.
Hey guys and this is i’m going to talk to you guys about calcium absorption and the role in importance of vitamin d and calcium absorption and why we actually need vitamin d to absorb calcium properly so to begin vitamin d is commonly absorbed from food or produced in the skin in the form of cholecalciferol or vitamin d3 now this form of vitamin d is not the active
Form that we require to adequately absorb calcium so what does it need to do well when you first absorb cholecalciferol it needs to undergo a couple of steps to be processed into the active form so what it does is cholecalciferol actually travels to the liver and will become called calcify do calcify do will then travel to the kidney where it is processed into
Calcitriol or the active form that we’re actually interested in the form that aids in calcium absorption so this brings up an important point guys that in order for a person to produce calcitriol in adequate amounts they actually need a healthy and functioning liver and a healthy and functioning kidney so this is important when we think about patients with renal
Failure in for calcium calcium actually requires calcitriol for adequate absorption and utilization so why is that well when we look at an entry site in the small intestine on the left we can see the intestinal lumen so say you have absorbed or ingested some calcium in your diet well the the process the basic process of calcium absorption goes like this calcium
Is brought into the intro site through a calcium transporter it binds to a protein in the in the cytosol known as cal bind indy this allows the calcium to be transported through the entry site and to the opposite side of the entry site so that it’ll can be pumped out of the entry site into the blood stream via an atp dependent calcium pump so why is calcitriol
So important in this process well when you have calcitriol it enters the entry site and it’ll actually bind to a protein known as vitamin d receptor or calcitriol receptor now this receptor is actually a transcription factor and it’ll actually bind to something else that is retinoid x receptor but that’s not important in this scheme so when it binds to vitamin d
Receptor the calcitriol will enter the nucleus where it’ll activate a genetic program so what is this genetic program do well the genetic program will actually increase the expression the translation transcription translation and expression of calcium transporters so that allows the inter site to uptake more calcium it’ll also actually increase the expression of
Cal bind and d so it will increase the amount of calvin dandy within the cytosol and last but not least it’ll also increase the activity of the atp dependent calcium pumps to allow the entry site to pump out even more calcium into the bloodstream so all of these processes will increase the uptake of calcium into the enter site and allow more calcium to be up taken
Or absorbed into the bloodstream so what is the recommended dietary intake of vitamin d in calcium well according to the national institute of health the recommended dietary allowance for vitamin d in early life zero to 12 months of age is 409 units per day from one to seven years of age it is recommended that a person should intake 600 international units per
Day and greater than seven years of age 800 international units so now what is the recommended dietary allowance for calcium well the recommended dietary allowance for calcium for infants from the ages of 0 to 6 months is 200 milligrams per day from 7 to 12 months of age 260 milligrams per day from 1 to 3 years of age 700 milligrams per day 4 to 8 years of age
1000 milligrams per day 9 to 18 years of age 1300 milligrams day 19 to 50 years of age 1000 milligrams per day 51 to 7 years of age 1000 milligrams for males and 1200 milligrams for females per day and over the age of 71 it is recommended that a person intake about 1200 milligrams of calcium per day so anyways guys that was a quick lesson on the role of vitamin d
In calcium absorption i hope you found it helpful if you did please like and subscribe for more lessons like this one anyways guys thank you so much for watching and have a great day
Transcribed from video
Vitamin D and Calcium Absorption – Biochemistry Lesson By JJ Medicine
