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  • Writer's pictureShruti GOCHHWAL

Why Your Body Needs Vitamin D to Absorb Calcium Supplements?

We know that the human body requires macronutrients like vitamins and minerals in order to perform optimally. Not only are they responsible for letting your body thrive but sometimes the availability or presence of one can directly affect the other.

This is why the presence of vitamin D³ in your body will affect the calcium levels in your body.


This mineral is one of the most essential minerals that the body requires. Calcium ions play an important role in the nervous system, heart, and muscle functions.

Most importantly, calcium ions form the building blocks of bones and thus bones act as a calcium factory that releases calcium ions whenever the body requires.

Thus, it creates a very give and take relationship as every time the body is lacking in ions, bones break down and release calcium ions into the blood. However, at the same time when a breakdown occurs, it also affects the structural function and importance of bones.

As humans age, we tend to consume a low calcium diet and this is why older adults suffer from bone problems like osteoporosis.

To prevent these complications, calcium supplements are prescribed by dietitians or orthopedics.

The Role of Vitamin D in Calcium Absorption

If you were to pick up a calcium supplement and read the nutritional information or the supplement facts, you will find a fair amount of vitamin D dosage that has been listed.

This is because calcium is practically non-effective if vitamin D is not present as the vitamin helps the body absorb these ions in your stomach.

Vitamin D can be absorbed from food, dietary shipments, or can even be produced in the skin. However, the form in which the body absorbs it is known as vitamin D3 or cholecalciferol.

This form of the vitamin is not active or capable of absorbing calcium ions. There are a couple of steps required for the vitamin to become active.

When cholecalciferol enters the blood street after absorption, it travels to the liver. The liver then converts it into calcifediol which is then transferred to the kidneys.

The kidneys eventually convert the vitamin to its active form and are known as calcitriol which is responsible for absorbing calcium ions.

This is why the body also requires healthy functioning of organs like the liver and kidneys in order to actively absorb calcium.

If you give supplements to a dialysis patient with renal failure, they will most likely be unable to increase their calcium levels as the kidneys are incapable of converting vitamin D3 into its active form.

In addition, to requiring calcitriol for absorption, the body also requires it to regulate the number of calcium ions to be utilized in various functions of the nervous systems, heart and muscle functions, or even regulating bone formation.

Recommended Dietary Intake (RDA)

They are the following:

1.   For Vitamin D (per day)

  1. 0-12 months: 400 IU

  2. 1-70 years: 600 IU

  3. ≥70 years : 800 IU

Credit: Wikimedia commons

Alt tag : calcium-rich foods

Caption: Calcium-rich foods

2.   For Calcium (per day)

  1. 0-6 months: 200mg

  2. 7-12 months: 260mg

  3. 1-3 years: 700mg

  4. 4-8years: 1000mg

  5. 9-18 years: 1300mg

  6. 19-50 years: 1000mg

  7. 51-70 years: 1000mg (males) and 1200 (females)

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