Britannica
Sources used in this answer
Why does vitamin D deficiency soften bones in adults?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
vitamin
Vitamin E in gel-cap form.
Vitamin D deficiency leads to the softening of bones in adults—a condition known as osteomalacia—primarily because it impairs the body's ability to maintain proper bone mineralization.123
The process functions as follows:
- Reduced Absorption: Vitamin D is essential for the efficient absorption of calcium and phosphate in the small intestine. A deficiency reduces this efficiency, leading to lower concentrations of these minerals in the blood.243
- Hormonal Imbalance: Low blood calcium levels trigger an increase in parathyroid hormone (PTH). While PTH attempts to restore blood calcium, it also causes the kidneys to excrete more phosphorus into the urine.243
- Poor Mineralization: Because the mechanical strength of bone is proportional to its mineral content, the resulting lack of available calcium and phosphorus prevents the skeleton from properly mineralizing. This leaves the bone matrix inadequately hardened, causing it to become soft and susceptible to fractures.124