WHERE DOES VITAMIN D COME FROM?

Vitamin D comes from three main sources:

1. Sunlight (Natural Production in the Skin)

• When your skin is exposed to ultraviolet B (UVB) rays from the sun, it produces vitamin D.
• The skin converts 7-dehydrocholesterol (a cholesterol compound) into vitamin D3 (cholecalciferol).
• Factors that affect production: time of day, season, latitude, skin pigmentation, age, and sunscreen use.

2. Food Sources

Only a few foods naturally contain vitamin D, but some are fortified:

• Fatty fish (salmon, mackerel, sardines, tuna) – richest natural source.
• Cod liver oil – very high in vitamin D.
• Egg yolks.
• Beef liver.
• Fortified foods (milk, plant-based milk, orange juice, breakfast cereals).
• Mushrooms exposed to UV light (provide vitamin D2, ergocalciferol).

3. Supplements

• Vitamin D2 (ergocalciferol) – from plants and yeast.
• Vitamin D3 (cholecalciferol) – from animal sources (or lichen in vegan supplements).
• D3 is more effective than D2 in raising and maintaining vitamin D levels in the blood.

🌞 So, in simple terms:

• Sunlight → main natural producer.
• Food → secondary source.
• Supplements → reliable backup when sun and diet aren’t enough.