Vitamin D and the Role it plays in Calcium Absorption

Vitamin D is a fat-soluble vitamin that is naturally present in very few foods, but also produced endogenously when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis. Vitamin D obtained from sun exposure, food, and supplements is absorbed as Cholecalciferol (Vitamin D3), its inactive form. Our bodies need the active form (Vitamin D2) so Cholecalciferol has to go through a process in order to become active. 

Cholecalciferol
is absorbed and travels to the liver where it is converted into Calcifediol. Calcifediol then goes to the kidneys to be processed before becoming the active form Calcitriol. As you can see in order to convert Vitamin D3 into Vitamin D2 you will need healthy functioning kidneys and liver. 

Calcium requires Calcitriol ( Vitamin D) for adequate absorption and utilisation.  Thats because the active form of Vitamin D increases the amount of calcium transporters into the cell, meaning that more calcium can be absorbed. Not only that but it also increases the activity of the calcium dependent pump, so more calcium can be pumped into the blood stream. This means that without adequate vitamin D in the body, you might not able to absorb and utilise as much calcium from the diet. 

Vitamin D is needed for bone growth and bone remodelling and without sufficient amounts, bones can become thin, brittle, or miss shaped. Vitamin D has other roles in the body, including modulation of cell growth, neuromuscular and immune function, and reduction of inflammation. 
Foods such as mushrooms, eggs & fish contain some Vitamin D and fortified foods such as plant based milks, cereals and bread. The recommended Daily Allowance (RDA) for Vitamin D for adults = 600-800IU/15mcg
The department of Health recommend that everyone should be taking a daily supplement containing at least 10mcg of Vitamin D per day. As with anything quality is important. Supermarket brands are likely to have more fillers, and be less bioavailable. Check out @cytoplan, @biocareltd or @viviolife which are all companies I love and trust.  

It is worth noting that taking excessive amounts of Vitamin D over a long period of time can lead to a build up of calcium in your blood (Hypercalcemia). However toxicity is quite rare. 

Calcium is needed for healthy bones and teeth, regulating muscle contractions, preventing blood clots and balancing blood pressure. Our bones are our bodies storage units for calcium. The Parathyroid hormone (PTH) tightly regulates the calcium levels in the blood stream by signalling for bones to break down and release calcium if blood levels are low.
Foods high in calcium include: Sesame seeds, Sardines, Yogurt, Spinach, Cheese, Milk, Cabbage, Broccoli, Salmon and Almonds. 
The recommended Daily Allowance (RDA) for Calcium for adults is1000-1200mg. That would look like 1 cup of yogurt, 1 cup of Spinach, 1tbsp tahini, 1 tin of sardines and 1 cup of broccoli in a day = around 1200mg of calcium. But remember you would need adequate Vitamin D to best utilise the calcium from this food. 


Love H x