Vitamin D is essential for bone strength and may support the immune system and other functions. The human body produces vitamin D as a response to sun exposure. A person can also boost their vitamin D intake through certain foods or supplements.
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.
Vitamin D plays a critical role in many bodily functions.
Vitamin D deficiency in children can cause rickets, leading to a bowlegged appearance due to the softening of the bones. Similarly, in adults, vitamin D deficiency
Long-term vitamin D deficiency can also present as osteoporosis.
An adequate intake of vitamin D may support good immune function and reduce the risk of autoimmune diseases.
While test-tube studies have shown vitamin D to have a
Although the body can create vitamin D, some people are more likely to be at risk of a deficiency than others. Factors that can influence this include:
- Skin color: Pigmentation in the skin reduces the body’s ability to absorb ultraviolet B (UVB) rays from the sun. Absorbing sunlight is essential for the skin to produce vitamin D.
- Lack of sun exposure: People who live in northern latitudes or areas of
high pollution, work night shifts, or are homebound should aim to consume vitamin D from food sources whenever possible.
- Breastfeeding: The American Academy of Pediatrics recommends that all breastfed infants receive
400 international units(IU) per day of oral vitamin D.
- Older adults: The skin’s ability to synthesize vitamin D
decreaseswith age. Older adults may also spend more time indoors.
- Those with conditions that limit fat absorption: 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.
- People with obesity: High levels of body fat can limit the body’s ability to absorb vitamin D from the skin.
- People following a gastric bypass: This surgery bypasses a part of the upper intestine that absorbs large amounts of vitamin D. This bypass can cause a deficiency.
These conditions can lead to secondary symptoms including:
- bone fragility, especially in older adults
- bone pain
- muscle twitching
- muscle weakness
- myalgias, or muscle pain
- arthralgias, or joint stiffness
If Vitamin D deficiency continues for long periods, it may result in complications, such as:
- cardiovascular conditions
- autoimmune problems
- neurological diseases
- pregnancy complications
- certain cancers, including breast, prostate, and colon
Infancy and childhood is a period of rapid growth bone growth. Due to this, it is essential for infants to get adequate amounts of vitamin D.
Chronic vitamin D deficiency
The American Academy of Allergy Asthma and Immunology (AAAAI) suggests a connection between low vitamin D exposure and an increased risk of allergic sensitization.
For example, children who live closer to the equator have lower rates of admission to the hospital for allergies and fewer prescriptions for epinephrine auto-injectors, or EpiPens. They are also less likely to have a peanut allergy.
Researchers of a
There may be an association between adequate vitamin D intake
People can often get the majority of their vitamin D intake from sunlight exposure. However, people at risk of developing vitamin D deficiency, and many other people, cannot solely rely on sunlight exposure for vitamin D production. During the winter months, when the sun is not as strong, everyone can benefit from vitamin D supplements.
The following foods are a source of vitamin D:
- fatty fish, such as salmon, mackerel, and tuna
- egg yolks
- beef liver
- fortified milk
- fortified cereals and juices
People can measure vitamin D intake in micrograms (mcg) or international units (IU). One mcg of vitamin D is equal to 40 IU.
|Demographic||Recommended daily intake|
|Infants 0-12 months||400 IU (10 mcg)|
|Children 1-18 years||600 IU (15 mcg)|
|Adults up to 70 years||600 IU (15 mcg)|
|Adults over 70 years||800 IU (20 mcg)|
|Pregnant or lactating women||600 IU (15 mcg)|
The upper limit that healthcare professionals recommend for vitamin D is
Vitamin D toxicity is typically the result of inappropriate supplement dosing and prescription errors.
Excessive vitamin D consumption can lead to hypercalcemia, or an excessively high blood calcium level. This can lead to calcification of bones and the hardening of blood vessels, kidneys, lungs, and heart tissues.
The most common symptoms of excessive vitamin D include headaches and nausea. However, too much vitamin D can also lead to the following:
Excessive vitamin D usually occurs from accidental overconsumption and prescription errors.
If someone is taking supplements, they should choose their brand carefully, as the Food and Drug Administration (FDA) does not monitor the safety or purity of supplements the same way it does pharmaceuticals.
A complete diet and regular eating pattern are most important in disease prevention and good health. It is better to eat a diet with various nutrients than to concentrate on only a few nutrients.
The body produces vitamin D due to sun exposure. Many foods and supplements also contain vitamin D. The vitamin plays an important role in maintaining bones, teeth, and optimal immune function.
A vitamin D deficiency can cause calcium deficiency disease, and hyperparathyroidism, a hormone imbalance that raises the blood calcium levels.