Vitamin D is essential for maintaining healthy bones. It plays a crucial role in regulating the body's levels of calcium and phosphate, which are vital for bone formation. Vitamin D controls these levels through three main mechanisms:
1. Absorption from our diet
2. Storage within our bones
3. Excretion from our body
We obtain vitamin D from three primary sources: diet, sun exposure, and supplements like multivitamins. Only a few foods naturally contain vitamin D, such as oily fish, certain mushrooms, and egg yolks. Most dietary vitamin D comes from fortified foods like dairy products, cereals, and bread. Sun exposure is a significant source of vitamin D, although sunscreen, which protects against sunburn and skin cancer, can reduce the skin's production of vitamin D.
What is Low Vitamin D?
Low vitamin D levels are common worldwide. In the United States, about 30% of the population has low vitamin D. Factors that increase the risk include insufficient dietary intake and limited sun exposure, particularly in colder climates and during winter.
Certain groups are more prone to low vitamin D levels, including women, older adults, and individuals with darker skin. Conditions such as obesity, kidney and liver failure, dietary malabsorption syndromes, and parathyroid issues are also linked to low vitamin D. Smoking and certain medications, such as oral steroids and some seizure drugs, can contribute to low levels, as can certain genetic disorders.
Low vitamin D is associated with several bone health issues, such as osteoporosis (low bone density) and rickets in children. People with chronic low vitamin D are more likely to have low bone density and a higher risk of fractures. Research has also connected low vitamin D levels to fractures in the foot or ankle and suggests that fractures are less likely to heal properly without adequate vitamin D.
What Can I Do If I Have Low Vitamin D?
Numerous studies have shown that taking vitamin D supplements can reduce the risk of fractures, including those of the foot, ankle, hip, and wrist. Improved fracture healing has also been observed in individuals taking vitamin D. Consequently, many doctors recommend testing vitamin D levels, particularly for those at risk of deficiency. Treatment usually involves oral vitamin D and calcium supplements.
Who Should Have Their Vitamin D Levels Checked?
Anyone who experiences a low-energy fracture (commonly known as a stress fracture), especially if it is slow to heal, should consult with a surgeon or primary care doctor about checking their vitamin D levels. Patients at high risk of low vitamin D due to medical conditions like kidney disease and parathyroid disorders should also discuss this test with their doctor.
What Level of Vitamin D is Considered Low?
Most doctors consider a vitamin D level of less than 30 ng/mL to be low. The goal of treatment is typically to raise vitamin D levels above 30 ng/mL.