7dehydrokolesterolista

7dehydrocholesterol, also known as provitamin D3, is a sterol found in the skin of humans and other animals. It plays a crucial role in the synthesis of vitamin D3. When skin is exposed to ultraviolet B (UVB) radiation from sunlight, 7dehydrocholesterol undergoes a photochemical reaction. This reaction converts it into previtamin D3, which then thermally isomerizes to vitamin D3. Vitamin D3 is essential for calcium and phosphate absorption in the intestines, which is vital for bone health and other physiological processes. The concentration of 7dehydrocholesterol in the skin can vary depending on factors such as age, skin pigmentation, and season. Individuals with darker skin have higher concentrations of melanin, which can absorb UVB radiation and reduce the amount of 7dehydrocholesterol converted to previtamin D3, potentially leading to lower vitamin D production. Deficiency in vitamin D can result in rickets in children and osteomalacia and osteoporosis in adults. Therefore, adequate sunlight exposure is important for maintaining sufficient levels of 7dehydrocholesterol and subsequent vitamin D synthesis. In some cases, dietary supplements are used to ensure adequate vitamin D intake.