**Vitamin D is prepared in our body with the help of sunlight.**

Sunlight is a natural source of ultraviolet B (UVB) radiation, which plays a crucial role in the production of vitamin D in our bodies. When sunlight penetrates our skin, it triggers a chemical reaction that converts a compound called 7-dehydrocholesterol into vitamin D3 (also known as cholecalciferol).

Here is a detailed explanation of how sunlight helps in the production of vitamin D:

**1. Ultraviolet B (UVB) radiation:** Sunlight contains UVB radiation, which has a shorter wavelength compared to UVA radiation. UVB radiation is responsible for stimulating the production of vitamin D in our bodies.

**2. Skin exposure:** When our skin is exposed to sunlight, the UVB radiation penetrates the outer layers of the skin and reaches the deeper layers where 7-dehydrocholesterol is present.

**3. Conversion of 7-dehydrocholesterol:** 7-dehydrocholesterol is a compound that is naturally present in our skin. When UVB radiation interacts with this compound, it undergoes a chemical reaction and is converted into pre-vitamin D3.

**4. Thermal conversion:** Pre-vitamin D3 is not yet biologically active. It needs to undergo a thermal conversion process in order to become fully active vitamin D3. This process occurs naturally in our body when the skin temperature increases due to sunlight exposure.

**5. Transport to the liver and kidneys:** Once the thermal conversion takes place, vitamin D3 is transported to the liver and kidneys, where it undergoes further modifications to become the active form of vitamin D called calcitriol. Calcitriol plays a crucial role in regulating calcium and phosphorus levels in our bodies, which are essential for bone health.

It's important to note that while sunlight is a natural source of vitamin D, excessive exposure to sunlight without protection can lead to sunburn and increase the risk of skin cancer. It is recommended to balance sun exposure with the use of sunscreen, protective clothing, and seeking shade during peak hours to maintain healthy levels of vitamin D while protecting the skin.

Vitamin D