Vitamin D is essential for the bones and teeth, the immune system, brain health, and for regulating inflammation. The body produces vitamin D as a response to sun exposure.
Certain foods and supplements can also boost vitamin D intake. Despite its name, vitamin D is not a vitamin but a hormone or prohormone.
In this article, we look at the benefits of vitamin D, what happens to the body when people do not get enough, and how to boost vitamin D intake.
Roles of vitamin D in the body
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Vitamin D plays a critical role in many bodily functions.
Healthy bones
Vitamin D promotesTrusted Source calcium absorption and helps maintain adequate levels of calcium and phosphorus in the blood, which is necessary for healthy bones and teeth.
Vitamin D deficiency in children can cause rickets, leading to a bowlegged appearance due to the softening of the bones, and dental problems, such as teeth not forming as they should.
Similarly, in adults, vitamin D deficiency can manifestTrusted Source as osteomalacia, or softening of the bones. Long-term vitamin D deficiency can also lead to osteoporosis, or low bone density, which increases the risk of fractures.
Immune function
An adequate intake of vitamin D may support good immune function and reduce the risk of autoimmune diseases.
ResearchersTrusted Source believe there may be a link between long-term vitamin D deficiency and the development of autoimmune conditions, such as type 1 diabetes and rheumatoid arthritis, but more research is necessary to confirm the link.
Vitamin D deficiency
Although the body can create vitamin D from sunlight, some people develop deficiencies. Factors that can influence this include:
Lack of sun exposure: People who live in northern climates or areas of high pollutionTrusted Source may not get as much vitamin D as others. Those who work night shifts or do not go outside can also develop a deficiency.
Skin color: Pigmentation in the skin reduces the body’s ability to absorb ultraviolet B (UVB) rays. Those with darker skin tones synthesize less vitamin D from sunlight than people with lighter skin.
Age: The skin’s ability to synthesize vitamin D decreases with age. Older adults may also spend more time indoors.
Breastfeeding: Babies cannot get enough vitamin D from breast milk on its own. The American Academy of Pediatrics recommends that exclusively and partially breastfed infants receive 400 international units (IU)Trusted Source per day of oral vitamin D until they are weaned. After weaning, they should get at least 1,000 mL/day vitamin D-fortified formula or whole milk. Children getting less than this, or who caregivers did not breastfeed, should take 400 IU vitamin D supplements.
Body weight: High levels of fat in the body can limit its ability to absorb vitamin D from the skin.
Certain medical conditions: Vitamin D is fat soluble, meaning intake is dependent on the gut absorbing dietary fats. Conditions that limit fat absorption can decrease vitamin D intake from the diet.
Gastric bypass surgery: This surgery bypasses a part of the upper intestine that absorbs large amounts of vitamin D. This bypass can cause a deficiency.
