Vitamin D is a fat-soluble vitamin that is essential for maintaining the balance of calcium and phosphorus in your body, which helps support strong bones and teeth¹. Here are some key points about Vitamin D:

Sources of Vitamin D

1. Sunlight: The body naturally produces Vitamin D when the skin is exposed to ultraviolet B (UVB) rays from the sun².
2. Food: Few foods naturally contain significant amounts of Vitamin D. Some dietary sources include:
   • Fatty fish (e.g., salmon, mackerel, sardines)
   • Egg yolks
   • Beef liver
   • Fortified foods (e.g., milk, cereals, orange juice)³⁴
3. Supplements: Vitamin D supplements are available in two forms: D2 (ergocalciferol) and D3 (cholecalciferol). Both forms can raise Vitamin D levels in the blood, but D3 may be more effective in maintaining those levels over time⁵.

Benefits of Vitamin D

• Bone Health: Vitamin D helps the body absorb calcium, which is crucial for bone formation and maintenance. Lack of Vitamin D can lead to conditions such as osteoporosis in adults and rickets in children⁶.
• Immune System: It supports the immune system, enhancing the body’s ability to fight off infections⁷.
• Muscle Function: Adequate levels of Vitamin D are necessary for muscle function⁸.
• Chronic Diseases: There is ongoing research into Vitamin D's role in preventing or managing conditions such as cardiovascular diseases, diabetes, and multiple sclerosis⁹.

Recommended Intake

• The Recommended Dietary Allowance (RDA) for most adults is 600 IU (International Units) per day, increasing to 800 IU for those over 70 years of age¹⁰.

Risk of Deficiency

• Vitamin D deficiency can occur due to limited sun exposure, inadequate dietary intake, certain medical conditions, and more¹¹. Symptoms of deficiency include bone pain, muscle weakness, and an increased risk of fractures¹².

Safety and Overdose

• While Vitamin D is generally safe when taken in recommended amounts, excessive intake can lead to Vitamin D toxicity, resulting in hypercalcemia (high levels of calcium in the blood), which can cause nausea, weakness, and kidney problems¹³.

For more detailed information, you can refer to authoritative sources like the Mayo Clinic and MedlinePlus.

Footnotes

1. Mayo Clinic ↩

2. Better Health Channel ↩

3. NHS ↩

4. MedlinePlus ↩

5. Harvard Nutrition Source ↩

6. MedlinePlus on Vitamin D Deficiency ↩

7. Office of Dietary Supplements ↩

8. Harvard Nutrition Source ↩

9. Passeri et al., Nutrients ↩

10. Harvard Nutrition Source ↩

11. MedlinePlus on Vitamin D Deficiency ↩

12. Mayo Clinic ↩

13. NIH - Office of Dietary Supplements ↩