Vitamin D is a fat-soluble vitamin essential for overall health, particularly for bones, muscles, and the immune system¹. Your body needs vitamin D to absorb calcium, which is crucial for the formation and maintenance of healthy bones¹.

How Your Body Gets Vitamin D

You can obtain vitamin D through three primary sources:

1. Sunlight: When your skin is exposed to ultraviolet B (UVB) rays from the sun, it synthesizes vitamin D. This is why it's often called the "sunshine vitamin"¹.
2. Diet: While very few foods naturally contain vitamin D, it can be found in fatty fish (like salmon, mackerel, and tuna), beef liver, cheese, and egg yolks. Moreover, many foods are fortified with vitamin D, such as milk, cereals, and orange juice².
3. Supplements: Vitamin D is available in supplement form, particularly as vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol)³. Both forms effectively raise vitamin D levels in your blood³.

Benefits

Vitamin D supports various bodily functions:

• Bone Health: It helps your body absorb calcium and phosphate, essential for bone formation and maintenance¹.
• Muscle Function: Needed for muscle movement⁴.
• Immune System: Plays a role in fighting off infections and diseases⁵.

Deficiency and Risks

A deficiency in vitamin D can lead to bone disorders such as rickets in children and osteomalacia or osteoporosis in adults¹. On the flip side, too much vitamin D can cause toxicity, leading to high blood calcium levels, resulting in nausea, vomiting, and kidney issues⁶.

Recommendations

The Recommended Dietary Allowance (RDA) for vitamin D varies by age and circumstance, typically ranging from 600 IU to 800 IU per day for adults⁷. However, supplementation may be necessary for individuals with limited sun exposure or dietary intake⁷.

Footnotes

1. MedlinePlus Medical Encyclopedia ↩ ↩² ↩³ ↩⁴ ↩⁵

2. Mayo Clinic ↩

3. Harvard T.H. Chan School of Public Health ↩ ↩²

4. NHS ↩

5. Office of Dietary Supplements - NIH ↩

6. Mayo Clinic News Network ↩

7. NCBI Bookshelf ↩ ↩²