☀️ Vitamin D: The Sunshine Vitamin and Its Deficiency
Why almost everyone is deficient in D and how to fix it
Vitamin D is a fat-soluble vitamin synthesized in the skin under sunlight. Due to lack of sun and office lifestyle, deficiency is common. Let's look at it in detail.
What is vitamin D
Vitamin D is actually a hormone. It regulates calcium absorption, immunity, bones, mood and muscles. The main form is cholecalciferol (D3), synthesized in the skin under UV-B.
- Fat-soluble vitamin/hormone.
- Synthesized in skin from sun.
- Regulates calcium and bones.
- Supports immunity.
Hidden deficiency
Vitamin D deficiency often runs hidden. Symptoms include chronic fatigue, frequent colds, hair loss, muscle and bone pain, low mood.
- Chronic fatigue.
- Frequent colds.
- Hair loss.
- Muscle and bone pain.
25(OH)D test
The most accurate marker is 25(OH)D (calcidiol). This test shows vitamin D stores. Result interpretation:
| 25(OH)D level | Interpretation |
|---|---|
| Below 20 ng/ml | Deficiency |
| 20–29 ng/ml | Insufficiency |
| 30–60 ng/ml | Optimal |
| Above 100 ng/ml | Possible excess |
Dosages
It is important to distinguish preventive and therapeutic doses (in IU):
| Goal | Dosage |
|---|---|
| Prevention | 800–2000 IU/day |
| Deficiency correction | 2000–5000 IU/day |
| Severe deficiency treatment | As prescribed |
Forms
Vitamin D comes in oil and water solutions. Difference in absorption:
- Oil solution — classic, absorbs well with fatty food.
- Water solution — suitable for fat absorption disorders.
- Both forms are effective when taken correctly.
- D3 (cholecalciferol) is preferred over D2.
Food sources
| Food | D content | Comment |
|---|---|---|
| Salmon | ~500 IU/100 g | Fish |
| Sardines | ~270 IU/100 g | Fish |
| Eggs (yolk) | ~40 IU/yolk | Eggs |
| Cod liver | ~10000 IU/100 g | Fish |
| Mushrooms | ~200 IU/100 g | Mushrooms |
Practice
- Take the 25(OH)D test.
- Prevention: 1000–2000 IU/day.
- For deficiency: 2000–5000 IU/day.
- Take with fatty food.
- Combine with vitamin K2 and magnesium.
- Retest after 3 months.
Why is everyone deficient in D?
Due to lack of sun, office lifestyle and sunscreen.
What are the deficiency symptoms?
Fatigue, frequent colds, hair loss, muscle and bone pain.
How to test vitamin D?
The 25(OH)D (calcidiol) test shows vitamin D stores.
How much vitamin D to take?
Prevention 800–2000 IU/day; for deficiency 2000–5000 IU/day.
Oil or water form?
Oil is usually sufficient; water for fat absorption disorders.
What 25(OH)D level is needed?
Optimal 30–60 ng/ml; below 20 is deficiency.
D3 or D2?
D3 (cholecalciferol) is preferred over D2.
Can D be obtained from food?
Partially, from fish and eggs; supplements or sun are needed for the norm.
What to combine D with?
With vitamin K2 and magnesium for better calcium absorption.
Is D overdose dangerous?
Yes, D accumulates; high doses without a test are dangerous.