Vitamin D — sun, supplement and testing
Vitamin D is a fat-soluble vitamin produced in the body when ultraviolet sunlight reaches the skin. In food it is present in comparatively small amounts.
Why people take it
At Georgia’s latitude, between November and March the angle of the sun is not sufficient for effective vitamin D synthesis. Levels therefore drop for many people over the winter months — especially for those who work in an office.
Supplements come in two forms: D2 (ergocalciferol, plant-derived) and D3 (cholecalciferol, from animal sources or lichen). D3 usually raises levels more effectively.
Two forms appear in supplements: D3 (cholecalciferol) and D2 (ergocalciferol). D3 raises blood levels more steadily and is used more often. Vitamin D is fat-soluble, so taking it with a meal that contains fat is more effective than on an empty stomach. At Georgia’s latitude the angle of the sun in the winter months is not enough for synthesis in the skin — which is why this is the most discussed supplement from October to March.
Permitted wordings and use
- Contributes to the normal absorption of calcium and phosphorus
- Contributes to the maintenance of normal bones
- Contributes to normal muscle function
- Contributes to the normal function of the immune system
Food sources
Sources include oily fish, egg yolk, liver and fortified products. Covering the full daily amount from food alone is difficult.
Who should be careful
Vitamin D is fat-soluble and accumulates in the body — taking high doses over a long period without medical supervision is dangerous. Before moving to a high dose, get a 25(OH)D test. With sarcoidosis, hypercalcaemia or kidney disease — only under medical supervision.
Frequently asked questions
Is a test worth doing?
If you plan long-term or high-dose intake — yes. A 25(OH)D test shows your actual level and helps a doctor choose the dose.
Do I need a supplement in summer?
In summer, if you spend time in the sun regularly, synthesis is usually sufficient. Winter is a different situation.
Is a blood test needed before starting?
The 25(OH)D test is used to see your level. It is not obligatory for preventive amounts, but it is useful if a large dose is planned for a long period — vitamin D is fat-soluble and accumulates in the body.
Is summer sun enough?
In summer a short midday exposure of hands and face is usually enough for synthesis, although this depends on skin type, age and sunscreen use. In winter, at Georgia’s latitude, that route practically closes.
Related ingredients
Category: Joints and muscles, Carbohydrate metabolism
This product is a food supplement, not a medicine. It is not intended to diagnose, treat, cure or prevent any disease.
The information on this page is for reference only and does not replace a consultation with a doctor or pharmacist. Consult a specialist before use if you are pregnant, breastfeeding, taking medication or living with a chronic condition. Do not exceed the recommended daily dose. Keep out of reach of children.