Vitamin d sources
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Main Sources of Vitamin D: Sunlight, Food, and Supplements
Vitamin D is unique because it can be made by the body when the skin is exposed to ultraviolet B (UVB) rays from sunlight, or it can be obtained from food and supplements. Sunlight is the primary natural source, but many people do not get enough sun exposure due to lifestyle, clothing, sunscreen use, or living in areas with limited sunlight, making dietary sources and supplements important for maintaining healthy vitamin D levels Benedik2021Janoušek2022Meza-Meza2020+3 MORE.
Sunlight as a Source of Vitamin D
The skin produces vitamin D when exposed to UVB rays from the sun. This process is the main way most people get their vitamin D. However, factors like spending time indoors, wearing covering clothes, using sunscreen, and living at high latitudes can reduce the amount of vitamin D the body makes from sunlight Benedik2021Janoušek2022Meza-Meza2020+3 MORE.
Dietary Sources of Vitamin D: Animal and Plant Foods
Animal-Based Foods
Animal foods are the main natural dietary sources of vitamin D, especially in the form of vitamin D3 (cholecalciferol). Fatty fish (such as salmon, mackerel, and sardines) and fish liver oils are particularly rich in vitamin D. Other animal products like beef liver, eggs (especially the yolk), and butter also contain vitamin D, but in smaller amounts. Most meats and unfortified dairy products are low in vitamin D Benedik2021Schmid2013Meza-Meza2020.
Plant-Based and Fungi Sources
Mushrooms are a notable non-animal source of vitamin D, mainly providing vitamin D2 (ergocalciferol). When exposed to sunlight or UV light, mushrooms can produce significant amounts of vitamin D2, sometimes enough to meet daily requirements in a single serving. Some lichens also contain high levels of vitamin D2 Benedik2021Cardwell2018.
Fortified Foods
Because few foods naturally contain high levels of vitamin D, many countries fortify foods such as milk, yogurt, breakfast cereals, orange juice, plant-based beverages, and fat spreads with vitamin D2 or D3. These fortified foods help people meet their daily vitamin D needs, especially where sun exposure is limited Benedik2021Dominguez2021Meza-Meza2020.
Vitamin D Supplements
Supplements are often recommended because it is difficult to get enough vitamin D from food alone, especially for people with limited sun exposure. Both vitamin D2 and D3 supplements are available, with D3 being the preferred form for most people due to its higher effectiveness in raising blood vitamin D levels Benedik2021Dominguez2021Janoušek2022+1 MORE.
Conclusion
The main sources of vitamin D for humans are sunlight exposure, animal-based foods (especially fatty fish and fish liver oils), UV-exposed mushrooms, fortified foods, and dietary supplements. Because many people do not get enough sun exposure or vitamin D-rich foods, supplements and fortified foods are important strategies to prevent vitamin D deficiency and support overall health Benedik2021Dominguez2021Schmid2013+6 MORE.
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Sources of vitamin D for humans.
Vitamin D can be obtained through sun exposure, dietary sources, and supplements, with fortified foods and certain fish, mushrooms, and lichen being rich sources.
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