Define vitamin D and its role in the body.

Vitamin D: vital for bones, immune system; synthesized from sunlight, found in foods/supplements. Deficiency causes health issues.

1. Requierment :

2. Functions :

Vitamin D aids calcium absorption, bone health, muscle function, nerve transmission, and may prevent diabetes. 

3. Deficiency :

Vitamin D deficiency: childhood rickets, adult osteoporosis, diabetes, cancer risks at higher latitudes.

4. Food sources :

->Mushrooms: 1.0mcg ->Tofu: 2mcg ->Crimini Mushroom: 1mcg ->Yogurt: 13 mcg ->Eggs: 2.12 mcg ->CHEESE: 0.5 mcg ->Cod live oil: 11 mcg ->Fish: 2.4 mcg ->Milk: 6.3mcg

5. Over Dosage :

Vitamin D toxicity at >374 nmol/L; hypercalcemia at >600 nmol/L.

6. Supplements :

7. Conclusion :

So, the best choice is to eat a well-balanced diet and get these nutrients from food sources.