Vitamin D is a fat-soluble vitamin that plays an important role in energy homeostasis, regulation of the immune and endocrine systems, and bone health. It is produced from the sun by your skin or obtained through supplements and foods. It helps your body absorb calcium and phosphorus, which are important for bone health.

It is essential to get adequate amounts of this vitamin, as low levels are linked with serious health problems such as rickets (softening of bones in children) and osteomalacia (softening of bones in adults).

Many people are deficient in vitamin D because they don’t eat enough food sources of vitamin D or don’t spend enough time outdoors getting exposure to sunlight. Some other risk factors for vitamin d deficiency include age, dark skin color, obesity, and taking certain medications that affect vitamin D metabolism.

Diet: Eating a diet rich in vitamin D-rich foods, fortified foods, and/or vitamin D supplements is the best way to get enough. These include fatty fish, milk, cheese, egg yolks, and fortified cereals.

Lifestyle: Some people don’t have much opportunity to get enough sun, especially during the winter. They may work in a place where the sun is not strong or they may be ill and have less time to get outside. They may also wear clothing that covers their entire bodies to protect them from the sun or for cultural or religious reasons.

Deficiency can lead to a variety of symptoms, including muscle weakness, aches and pains, brittle bones, and symmetric low back pain that is aggravated when bending over. Other symptoms can include irritability, lethargy, confusion, or developmental delay.

The main risk factors for severe deficiency include:

Chronic kidney disease and hemodialysis patients; renal transplant recipients, people who take medicine that can interfere with vitamin D metabolism, people with celiac disease or Crohn’s disease, and people who are obese.

Severe vitamin D deficiency with a 25-hydroxyvitamin D (25(OH)D) level below 30 nmol/L or 12 ng/ml is associated with increased risk of mortality, infections, and other diseases. The treatment goal is to normalize the level and prevent these complications from developing.

Vitamin D deficiency is a common problem and often goes undiagnosed. It is often asymptomatic, but it can be treated to relieve symptoms and reduce your risk of developing osteoporosis and fractures. Talk with your doctor about how to treat your deficiency.