Which vitamin is referred to as a hormone and helps with bone growth and density?

Vitamin D is often referred to as a hormone due to its role in the regulation of calcium and phosphate in the body, which is crucial for maintaining healthy bones. When the skin is exposed to sunlight, it synthesizes vitamin D, which then undergoes further transformations in the liver and kidneys to become its active form, calcitriol. This active form functions similarly to a hormone by signaling for the absorption of calcium in the intestines and regulating calcium levels in the blood.

Additionally, vitamin D supports the activity of osteoblasts and osteoclasts, the cells responsible for bone formation and resorption, respectively. Adequate levels of vitamin D contribute to increased bone mineral density and may help prevent conditions such as osteoporosis. This is why it is essential for overall bone health, and its classification as a hormone emphasizes its vital and regulatory role in the body rather than just a dietary nutrient.