Understanding Vitamin D: Functions, Sources, and Recommended Intake
Learn about the essential roles of Vitamin D in bone health, immune function, and muscle activity. Discover its natural sources, including sunlight and food, and get insights into the recommended daily intake to avoid deficiency and excess.
what is vitamind d?
Vitamin D is a fat-soluble vitamin that plays a critical role in various body processes. Here's an overview:
Functions of Vitamin D
- Bone Health: Vitamin D promotes calcium absorption in the gut, which is essential for maintaining healthy bones and teeth12. Insufficient vitamin D can lead to bone diseases such as osteoporosis and rickets3.
- Immune System: It supports the immune system in combating pathogens2.
- Muscle Function: Vitamin D is vital for muscle function as it helps muscles move2.
- Nervous System: It aids in the functioning of the nervous system by helping nerves carry messages between the brain and the body2.
Sources of Vitamin D
- Sunlight: The skin synthesizes vitamin D upon exposure to sunlight4. However, excessive sun exposure can lead to skin aging and skin cancer4.
- Food: Few foods naturally contain vitamin D. These include:
- Supplements: Vitamin D supplements are available in two forms: D2 (ergocalciferol) and D3 (cholecalciferol). Both effectively increase vitamin D levels, but D3 might maintain higher levels for longer67.
Recommended Intake
The recommended daily allowance (RDA) for vitamin D is:
- 600 IU (15 mcg) for adults between 19-70 years
- 800 IU (20 mcg) for adults older than 70 years7
Deficiency and Excess
- Deficiency: Deficiency can lead to conditions like osteomalacia in adults and rickets in children12. Long-term deficiency can also lead to osteoporosis1.
- Excess: Excessive vitamin D can cause health issues, though the exact adverse effects are still being studied5.
Footnotes
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https://www.mayoclinic.org/drugs-supplements-vitamin-d/art-20363792 ↩ ↩2 ↩3 ↩4 ↩5
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https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/ ↩
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https://www.bhf.org.uk/informationsupport/heart-matters-magazine/nutrition/ask-the-expert/foods-high-in-vitamin-d ↩ ↩2
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https://ods.od.nih.gov/factsheets/VitaminD-Consumer/ ↩ ↩2 ↩3 ↩4
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https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/ ↩ ↩2