Vitamin D, commonly known as the “sunshine vitamin,” is primarily synthesized in the skin upon exposure to ultraviolet B (UVB) rays from sunlight. This process involves the conversion of 7-dehydrocholesterol, a cholesterol derivative in the skin, into previtamin D3, which subsequently becomes vitamin D3 (cholecalciferol). [1]
Dietary sources such as fatty fish, mushrooms, and egg yolks contribute to vitamin D intake, but they generally provide lower amounts compared to what the body produces through sun exposure. [2]
Once synthesized or ingested, vitamin D undergoes hydroxylation in the liver to form 25-hydroxyvitamin D (calcidiol). It is then further hydroxylated in the kidneys to produce 1,25-dihydroxyvitamin D (calcitriol), the active form of the vitamin. Calcitriol functions as a hormone, regulating calcium and phosphate metabolism to maintain healthy bones and has roles in immune system modulation and other physiological processes. [1]
Vitamin D is essential for calcium absorption, promoting strong bones and teeth, and reducing the risk of conditions like rickets, osteomalacia, osteoporosis, and fractures. [1] Beyond bone health, it supports muscle function, cardiovascular health, and the immune system by reducing inflammation and aiding in infection defense. [3] Research also suggests that adequate vitamin D levels may help regulate mood and alleviate symptoms of depression. [4]
While sunlight is a natural and effective source of vitamin D, factors such as skin pigmentation, geographic location, and sunscreen use can influence its synthesis. For instance, individuals with darker skin tones have higher melanin levels, which can reduce the skin’s ability to produce vitamin D compared to those with lighter skin tones. [5] Additionally, sunscreen with a sun protection factor (SPF) of 8 can reduce vitamin D production in the skin by more than 95%. [6]
To ensure you get enough Vitamin D while avoiding the risks of overexposure to sunlight, check out Sola in the App Store. The Sun UV & Vitamin D tracking companion helps you monitor your Vitamin D levels and manage safe sun exposure, so you can stay healthy while protecting your skin.
References:
1. Vitamin D Synthesis
2. Healthy Foods That Are High in Vitamin D
3. Vitamin D and Its Impact on Immunity and Mood
4. Can Vitamin D Deficiency Lead to Depression?
5. How is Vitamin D Synthesized in the Skin?
6. Vitamin D and Skin Health
