Vitamin D is an essential vitamin that plays a role in normal bone development and maintenance, as well as in the nervous, musculoskeletal, and immune systems. A deficiency in vitamin D can cause a variety of issues, including:

• Bone and muscle problems: Vitamin D deficiency can lead to a loss of bone density, which can contribute to osteoporosis and fractures (broken bones). Severe vitamin D deficiency can also lead to other diseases, such as osteomalacia, which causes weak bones, bone pain, and muscle weakness.

• Fatigue and weakness: Symptoms of vitamin D deficiency may include fatigue, muscle weakness, and bone pain or achiness.

• Mood changes: Vitamin D deficiency has been linked to depression or feelings of sadness.

• Hair loss: In some cases, vitamin D deficiency can cause hair loss.

• Increased risk of certain diseases: Vitamin D deficiency has been associated with an increased risk of certain diseases, such as rickets in children and falls in older adults.

The two main causes of vitamin D deficiency are not getting enough vitamin D in your diet and not getting enough exposure to sunlight. Other factors that can put you at a greater risk of developing vitamin D deficiency include older age, having darker skin, and certain medical conditions that affect your ability to absorb or convert vitamin D. If you are at risk for vitamin D deficiency, talk to your healthcare provider about getting a blood test to measure your vitamin D levels.