Vitamin D is a fat-soluble vitamin. Fat-soluble vitamins are stored in the body's liver and fatty tissues. Vitamin D acts as both a vitamin and a hormone. Vitamin D is found in some foods, but the main sources are vitamin D-fortified milk and sunlight. The ultraviolet rays of the sun react with cholesterol present in the skin and create previtamin D3. This compound goes through a series of reactions in the kidneys and the liver, and the final product is vitamin D.
Vitamin D's functions:
- Plays a crucial role in the growth and maintenance of strong, healthy bones
- Maintains normal blood levels of calcium and phosphorus
In children with low vitamin D levels, supplementation can improve bone mineral density. While the evidence does not give a clear answer, it has also been suggested that vitamin D supplementation may reduce the risk of osteoporosis
, high blood pressure
, and some forms of cancer. Vitamin D has also been found to improve pain symptoms in patients with low vitamin D levels.
Here are the guidelines for vitamin D intake:
|Age Group ||Recommended Dietary Allowance or Adequate Intake (IU/Day) |
|0-12 months ||400 |
|1-70 years ||600 |
|71+ years ||800 |
|Pregnant or nursing women ||600 |
IU: international unitsThe American Academy of Pediatrics recommends supplementation for all children who do not receive at least 400 IU of vitamin D daily. Breastfed babies may require a supplement within the first few days of life. Bottle-fed babies who do not consume enough vitamin-D fortified formula may also need the supplement, as well as any child who does not get plenty of vitamin D in their diet.As seen above, requirements for pregnant women are the same as for healthy adults, though some believe that pregnant mothers should take more vitamin D than recommended. Furthermore, some experts believe that people at highest risk for vitamin D deficiency, such as older adults or those with limited sun exposure during the winter months, should take 1,000 IU or more daily. However, since the risk of vitamin D toxicity increases with higher doses, such recommendations ought to be discussed individually with a physician.