Core prompt：Vitamin D, also known as the sunshine vitamin, can be produced in the body with mild sun exposure or consumed
Vitamin D, also known as the sunshine vitamin, can be produced in the body with mild sun exposure or consumed in food or supplements.
Adequate vitamin D intake is important for the regulation of calcium and phosphorus absorption, maintenance of healthy bones and teeth, and is suggested to supply a protective effect against multiple diseases and conditions such as cancer, type 1 diabetes and multiple sclerosis.
Vitamin D has multiple roles in the body, helping to:
Maintain the health of bones and teeth
Support the health of the immune system, brain and nervous system
Regulate insulin levels and aid diabetes management
Support lung function and cardiovascular health
Influence the expression of genes involved in cancer development.
In spite of the name, vitamin D is considered a pro-hormone and not actually a vitamin. This is because the body is capable of producing its own vitamin D through the action of sunlight on the skin, while vitamins are nutrients that cannot be synthesized by the body and must be acquired through the diet or supplements.
It is estimated that sensible sun exposure on bare skin for 5-10 minutes 2-3 times per week allows the body the ability to produce sufficient vitamin D, but vitamin D has a half-life of only two weeks, meaning that stores can run low, especially in winter. Recent studies have suggested that up to 50% of adults and children worldwide are vitamin D deficient. There are several likely factors contributing to vitamin D deficiency, which will be looked at further in this article.
Vitamin D is produced when sunlight converts cholesterol on the skin into calciol (vitamin D3). Vitamin D3 is then converted into calcidiol (25-hydroxyvitamin D3) in the liver. The kidneys then convert calcidiol into the active form of vitamin D, called calcitriol (1,25-hydroxyvitamin D3). As such, statins and other medications or supplements that inhibit cholesterol synthesis, liver function or kidney function can impair the synthesis of vitamin D.
Here are some key points about vitamin D. More detail and supporting information is in the main article.
Vitamin D's primary role is to support the development and maintenance of bones and teeth.
A fair-skinned person with full body exposure to the sun can synthesize up to 20,000 IU of vitamin D3 in 20 minutes.
Vitamin D deficiency is common, especially in the elderly, infants, people with dark skin and people living at higher latitudes or who get little sun exposure.
Vitamin D deficiency has been seen in up to 80% of hip fracture patients.
800IU of vitamin D per day reduces the risk of fracture by 20% in the elderly and decreases the risk of falls.
The metabolism of vitamin D may be affected by some medications, including barbiturates, phenobarbital, dilantin, isoniazid and statin drugs.
Recommended intake of vitamin D
Vitamin D intake can be measured in two ways: in micrograms (mcg) and International Units (IU). One microgram of vitamin D is equal to 40 IU of vitamin D. The recommended intakes of vitamin D throughout life were updated by the US Institutes of Medicine (IOM) in 2010 and are currently set at:
Infants 0-12 months - 400 IU (10 mcg)
Children 1-18 years - 600 IU (15 mcg)
Adults to age 70 - 600 IU (15 mcg)
Adults over 70 - 800 IU (20 mcg)
Pregnant or lactating women - 600 IU (15 mcg).
Although the body has the ability to make vitamin D, there are many reasons deficiency occurs. Darker skin pigments and sunscreen use can significantly decrease the body's ability to absorb the ultraviolet radiation B (UVB) rays required to produce vitamin D.
vitamin d written in sand
The sunshine vitamin - vitamin D - can be produced in the body with sun exposure or consumed in food or supplements.
A sunscreen with sun protection factor (SPF) 30 can reduce the body's ability to synthesize the vitamin by 95%. The skin also has to be directly exposed to the sunlight, not covered by clothing, in order to start vitamin D production. Even the angle at which sunrays hit the earth can affect absorption.
People who live in northern latitudes or areas of high pollution, work at night and stay home during the day or are homebound should aim to consume extra vitamin D from food sources whenever possible. Infants who are exclusively breastfed are also at high risk of vitamin D deficiency, especially if they are dark-skinned or have minimal sun exposure. The American Academy of Pediatrics recommends that all breastfed infants receive 400 IU/day of an oral vitamin D supplement.
Vitamin D supplements are available, but it is best to obtain any vitamin or mineral through natural sources first. It is not the individual vitamin or mineral alone that make certain foods an important part of our diet, but the synergy of that foods nutrients working together and allowing for greater absorption. For example, vitamin D is fat soluble, meaning that its absorption requires dietary fat. In addition, magnesium is needed to convert vitamin D into its active form.
It has been proven time and again that isolating certain nutrients in supplement form will not provide the same health benefits as consuming the nutrient from a whole food. First focus on obtaining your daily vitamin D requirement from sunlight and foods then use supplements as a backup.
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