What vitamin is from the sun
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The Role of Sunlight in Vitamin D Production
Vitamin D Synthesis from Sunlight
Sunlight and Vitamin D Production
Vitamin D, often referred to as the "sunshine vitamin," is primarily synthesized in the skin through exposure to ultraviolet B (UVB) radiation from the sun. When UVB photons are absorbed by 7-dehydrocholesterol in the skin, they are converted to previtamin D3, which is then rapidly transformed into vitamin D3 (cholecalciferol)1 2. This process is influenced by several factors, including the season, latitude, time of day, skin pigmentation, aging, and the use of sunscreen or glass barriers1 2 4.
Metabolism of Vitamin D
Once formed in the skin, vitamin D3 undergoes further metabolism in the liver to become 25-hydroxyvitamin D3 (25(OH)D), the major circulating form of vitamin D. It is then converted in the kidneys to its biologically active form, 1,25-dihydroxyvitamin D3 (calcitriol), which plays a crucial role in calcium and phosphate metabolism, essential for maintaining bone health and other metabolic functions1 2.
Health Benefits of Vitamin D
Bone Health and Disease Prevention
Vitamin D is vital for bone health, preventing conditions such as rickets in children and osteomalacia and osteoporosis in adults. It enhances calcium absorption in the intestines, which is crucial for maintaining strong bones1 2 7. Additionally, adequate vitamin D levels are associated with a reduced risk of several chronic diseases, including autoimmune diseases, cardiovascular diseases, and certain cancers1 2 3 9.
Immune System and Chronic Diseases
Vitamin D receptors are present in most cells and organs, allowing vitamin D to influence numerous biological pathways. This widespread presence helps explain the associations between vitamin D deficiency and increased risks of autoimmune diseases, infectious diseases, and various cancers2 3 9. For instance, higher vitamin D levels have been linked to a lower risk of colorectal, breast, and prostate cancers3.
Factors Affecting Vitamin D Synthesis
Influence of Environmental and Personal Factors
The efficiency of vitamin D synthesis can be significantly affected by environmental factors such as latitude, season, and time of day. For example, during winter months or in higher latitudes, the intensity of UVB radiation is insufficient for adequate vitamin D production4 6. Personal factors like skin pigmentation, age, and the use of sunscreen also play a role. Darker skin has more melanin, which reduces the skin's ability to produce vitamin D from sunlight1 2 4.
Sun Exposure Recommendations
To maintain sufficient vitamin D levels, sensible sun exposure is recommended. This typically involves exposing the arms and legs or the hands, arms, and face to sunlight for about 5-10 minutes, 2-3 times per week, depending on the individual's skin type and environmental conditions1 2. However, excessive sun exposure should be avoided due to the risk of skin cancer1 5.
Conclusion
Sunlight is a critical source of vitamin D, essential for bone health and the prevention of various chronic diseases. While factors such as season, latitude, and personal characteristics can influence vitamin D synthesis, sensible sun exposure remains a key strategy for maintaining adequate vitamin D levels. In cases where sun exposure is insufficient, dietary supplements can help achieve the necessary vitamin D status to support overall health.
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Most relevant research papers on this topic
Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease.
Sunlight and vitamin D are essential for bone health, autoimmune diseases, cancers, and cardiovascular disease prevention.
Highly CitedSunlight and Vitamin D
A three-part strategy involving food fortification, sensible sun exposure, and vitamin D supplementation can prevent global vitamin D deficiency and its negative health consequences.
Highly CitedVitamin D and sunlight: strategies for cancer prevention and other health benefits.
Increasing vitamin D intake and sun exposure can reduce the risk of developing colorectal, breast, and prostate cancer by 30 to 50%.
Highly CitedContributions of Sunlight and Diet to Vitamin D Status
Sunlight and diet contribute to vitamin D status, with factors like sun avoidance, melanin, and sunscreen reducing synthesis, and fortifying foods with vitamin D.
Rigorous JournalHighly CitedVitamin D, sun, sunbeds and health
Improved vitamin D status may be more important than the potential increased risk of cutaneous malignant melanoma from carefully increasing UV exposure.
Systematic ReviewRigorous JournalSunshine is an Important Determinant of Vitamin D Status Even Among High‐dose Supplement Users: Secondary Analysis of a Randomized Controlled Trial in Crohn's Disease Patients
Sunshine is an important determinant of vitamin D status, even in those taking high-dose supplements and living at higher mid-latitude locations.
RCTLow vitamin D status despite abundant sun exposure.
Variable responsiveness to UVB radiation causes some individuals to have low vitamin D status despite abundant sun exposure, suggesting the need for vitamin D supplementation.
Observational StudyHighly CitedThe vitamin D epidemic and its health consequences.
Vitamin D deficiency can lead to bone deformities, osteoporosis, muscle weakness, and increased risk of various diseases and cancers.
Highly CitedEffect of sun exposure versus oral vitamin D supplementation on serum 25-hydroxyvitamin D concentrations in young adults: A randomized clinical trial.
Enhanced sun exposure and 500 IU/d of oral vitamin D3 supplementation both significantly increased serum 25-hydroxyvitamin D concentrations, but oral vitamin D3 supplementation was more effective for vitamin D deficiency.
RCT
Very Rigorous JournalVitamin D deficiency: a worldwide problem with health consequences.
Vitamin D deficiency is a global issue, leading to rickets, osteopenia, osteoporosis, and fractures, and increasing the risk of common cancers, autoimmune diseases, hypertension, and infectious diseases.
Very Rigorous JournalHighly Cited