Vitamin D is a fat-soluble vitamin that plays an important role in calcium and phosphate metabolism and therefore in bones and muscles. What makes it special is that the body can produce vitamin D itself in the skin when exposed to sunlight, while the intake from foods such as oily fish, egg yolk or fortified products is comparatively low.
In regions with little sunlight, especially in the autumn and winter months, the body's own production may not be enough to cover the requirement fully. A deficiency is often identified through a blood test, since outward signs are non-specific.
Relevance for nutrition and sport
Vitamin D is associated with bone health and muscle function, among other things, which makes it relevant for physically active people too. A balanced diet alone often covers the requirement only in part, which is why regular time outdoors makes an important contribution for many people.
Whether a vitamin D supplement makes sense can be judged most reliably from a measured blood value. Before supplementing, especially at higher doses, medical advice should therefore be sought, as an excess or shortfall can differ from person to person. The overview vitamins explains further nutrients of similar relevance for sport.
