Britannica Sources used in this answer

How can a lack of vitamin D lead to rickets in children?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

A labeled diagram of the periodic table entry for calcium, showing its atomic number 20, symbol Ca, atomic weight 40.078, electron configuration, and classification as an alkaline-earth metal. Icons indicate calcium is a solid with a face-centered cubic crystal structure and strongly basic oxides at room temperature. — calcium The chemical element calcium is the most abundant metallic element in the human body.

Vitamin D is essential for maintaining healthy calcium levels, which are necessary for bone rigidity. In the body, vitamin D is converted into its active form, calcitriol, which stimulates the small intestine to absorb calcium and phosphate from the diet.12

When a child lacks sufficient vitamin D, the body cannot efficiently absorb these minerals, leading to low serum calcium concentrations. In response, the parathyroid glands secrete parathormone, which pulls calcium from the bones to maintain blood levels. Although the body continues to produce the protein matrix (osteoid) for bone growth, the lack of calcium means this matrix remains poorly calcified. This results in the softening of the bones characteristic of rickets, causing skeletal deformities and stunted growth.132