Overview of Vitamin D

Functions and Benefits

Vitamin D is a fat-soluble vitamin crucial for the absorption of calcium and phosphorus, essential minerals for maintaining healthy bones, teeth, and muscles¹². It also plays roles in reducing inflammation, modulating cell growth, and regulating immune function².

Sources of Vitamin D

1. Sunlight: The body synthesizes vitamin D when the skin is exposed to UVB radiation from the sun.
2. Dietary Sources:
   • Natural Sources: Fatty fish (e.g., salmon, tuna), fish liver oils, egg yolks, and beef liver.
   • Fortified Foods: Milk, cereals, orange juice, soy beverages, and some margarine.
3. Supplements:
   • Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol) are the two main forms available³.

Deficiency and Risks

A deficiency in vitamin D can lead to:

• In children, rickets—a condition characterized by soft and weak bones.
• In adults, osteomalacia and increased risk of osteoporosis¹³.

Excess and Toxicity

Excessive intake of vitamin D can result in:

• Hypercalcemia, leading to nausea, vomiting, weakness, and serious complications like kidney damage⁴.

Recommendations

General recommendations suggest daily vitamin D intake through a combination of sunlight exposure, diet, and possibly supplements, especially during months with limited sunlight⁵.

Footnotes

1. MedlinePlus: Vitamin D ↩ ↩²

2. Office of Dietary Supplements - Vitamin D ↩ ↩²

3. Benedik, Sources of vitamin D ↩ ↩²

4. NHS: Vitamin D ↩

5. Office of Dietary Supplements - Vitamin D ↩