Vitamin D and calcium: How does vitamin D help calcium absorption

January 15, 2020

Calcium helps support healthy and strong bones, but it is not alone. Phosphorus helps repair our bones, and vitamin D acts as the glue for your body to absorb calcium and phosphorus. Vitamin D plays a key role in helping our body absorb phosphorus and maintaining a healthy balance of calcium and phosphorus in the blood. That makes vitamin D a critical component to maintaining healthy and strong bones.

Vitamin D and calcium absorption

Both calcium and phosphorus absorption takes place in the intestinal tract, particularly in the lower segment of the small intestine, which is called the ileum. In fact, 70 to 80 per cent of calcium absorption occurs in this specific area of the intestines. [1] The entry of calcium and phosphorus into the digestive tract is positively enhanced by the presence of Vitamin D. [1] The presence of Vitamin D is key to getting calcium and phosphorus to enter the bloodstream via the gut.

When our body is low on vitamin D it can result in insufficient levels of both calcium and phosphorus, contributing to soft, brittle, or deformed bones. Maintaining proper levels of vitamin D has been associated with the prevention of softening and weakening of bones in children, a condition known as rickets, and a related bone modifying condition known as osteomalacia in adults. Vitamin D and calcium are often recommended for older adults who are at risk of osteoporosis. The challenge with osteoporosis is that there is a slow reduction in bone mass over time, sometimes with very few symptoms until the pain is experienced with a bone break. These painful fractures may occur in any bones, including stress fractures of the feet, the small bones of the back, or in the hip as a result of a fall. [2,3]

Consider vitamin D as a doorman in the gut. As a doorman, it is responsible for opening the door and allowing the minerals calcium and phosphorus to enter. Once in the gut, calcium and phosphorus are free to move throughout the body to do what they do best; strengthen, repair, and build bone and teeth. But without vitamin D, it would have been very difficult for either calcium or phosphorus to enter.

Whether you are getting your vitamin D from sunlight, food, or a supplement, like Ddrops®, know that calcium and phosphorus are also on the way to help maintain healthy and strong bones.


This article was reviewed and updated in August 2019

  1. R.H. Wasserman. Vitamin D and the Dual Processes of Intestinal Calcium Absorption. J. Nutr. November 1, 2004 vol. 134 no. 11 3137-3139
  2. The National Academy of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press, 2010.
  3. William Shiel Jr. & Catherine Burt Driver, Osteoporosus.
Tags: bone, calcium, sun, teeth, vitamin D