How does sun exposure affect vitamin D?

Sun exposure plays a crucial role in vitamin D synthesis. Ultraviolet B (UVB) radiation from the sun activates the production of vitamin D3 in the skin. This process, however, is influenced by several factors:

1. Sunscreen and Skin Pigmentation: Sunscreen and melanin (the pigmentation in the skin) block UVB radiation, which is necessary for vitamin D synthesis. This means that individuals with darker skin or those using sunscreen may require longer sun exposure to produce adequate levels of vitamin D 1.

2. Age and Body Mass: The efficiency of vitamin D production from sun exposure diminishes with age. Older individuals produce significantly less vitamin D compared to their younger selves. Additionally, higher body mass can reduce the bioavailability of vitamin D3, as it is sequestered in fat tissues 1.

3. Geographical and Seasonal Variations: UVB radiation varies with geographic location and season. People living at higher latitudes or during winter months may not receive adequate UVB radiation, impacting vitamin D synthesis 2.

4. Supplementation Need: Due to these limitations, supplementation becomes important, especially for individuals at risk of deficiency, including those with darker skin, older adults, or those living in regions with limited sun exposure during certain times of the year 1.

In summary, while sun exposure is a natural source of vitamin D, various factors such as skin pigmentation, use of sunscreen, age, body mass, and geographic location affect the efficiency of vitamin D production from sunlight.