{"id":11018507,"date":"2026-07-09T13:37:18","date_gmt":"2026-07-09T13:37:18","guid":{"rendered":"https:\/\/labtest.nl\/?post_type=biomarker&p=11018507"},"modified":"2026-08-18T12:48:38","modified_gmt":"2026-08-18T12:48:38","slug":"vitamin-d","status":"publish","type":"biomarker","link":"https:\/\/labtest.nl\/en\/biomarker\/vitamin-d\/","title":{"rendered":"Vitamin D"},"content":{"rendered":"\n

What is vitamin D important for?<\/h2>\n\n\n\n

Vitamin D is important for strong bones and teeth. It helps your body absorb calcium from your diet. Vitamin D also supports your muscles and immune system, helping your body protect itself against illness.<\/p>\n\n\n\n

How can you tell if you have a vitamin D deficiency?<\/h2>\n\n\n\n

A vitamin D deficiency often does not cause noticeable symptoms straight away. Possible symptoms include fatigue, muscle pain, muscle weakness, bone pain or getting ill more frequently. A severe deficiency can lead to weakened bones or muscle weakness.<\/p>\n\n\n\n

Why do many people have a vitamin D deficiency?<\/h2>\n\n\n\n

Many people have a vitamin D deficiency because they spend little time outdoors or regularly cover their skin. In the Netherlands, sunlight during autumn and winter is not strong enough for the skin to produce sufficient vitamin D. Older age, darker skin and certain medical conditions can also increase the risk of deficiency.<\/p>\n\n\n\n

Can you get enough vitamin D from sunlight?<\/h2>\n\n\n\n

During spring and summer, you can usually produce enough vitamin D if your hands and face are regularly exposed to sunlight (approximately 15\u201330 minutes per day). During autumn and winter, sunlight in the Netherlands is too weak, so your body produces less vitamin D.<\/p>\n\n\n\n

Which foods are rich in vitamin D?<\/h2>\n\n\n\n

Vitamin D is mainly found in oily fish, such as salmon, mackerel and herring. Cod liver oil, eggs and meat also contain some vitamin D. In the Netherlands, vitamin D is also added to margarine, low-fat margarine and certain cooking and baking fats.<\/p>\n\n\n\n

Who is at greater risk of a vitamin D deficiency?<\/h2>\n\n\n\n

Older adults, people with darker skin, pregnant women, young children, people who spend little time outdoors or cover their skin, and people with certain medical conditions (such as intestinal disorders) have a greater risk of vitamin D deficiency.<\/p>\n\n\n\n

How quickly can you correct a vitamin D deficiency?<\/h2>\n\n\n\n

With supplements, a vitamin D deficiency can usually be corrected within a few weeks to several months. How quickly this happens depends on the severity of the deficiency and the amount of vitamin D you take. Your doctor can advise you on this.<\/p>\n\n\n\n

When should you consider having your vitamin D tested?<\/h2>\n\n\n\n

It may be advisable to have your vitamin D tested<\/a> if you have symptoms that could indicate a deficiency, such as muscle weakness or bone pain. If you belong to a higher-risk group (for example, older adults, people with darker skin or people who spend little time outdoors), it may also be useful to have your vitamin D level checked<\/a>. Discuss this with your doctor.<\/p>\n\n\n\n

This article is for informational purposes only and is not a substitute for medical advice from a doctor. If your symptoms persist or you are concerned, always contact your doctor.<\/em><\/p>\n","protected":false},"author":2,"featured_media":0,"menu_order":0,"template":"","meta":{"_acf_changed":false,"footnotes":""},"biomarker_category":[593],"biomarker_material":[],"class_list":["post-11018507","biomarker","type-biomarker","status-publish","hentry","biomarker_category-vitamin-d"],"acf":[],"yoast_head":"\nVitamin D: Function, symptoms and vitamin D deficiency<\/title>\n<meta name=\"description\" content=\"Everything about Vitamin D. Discover its function, symptoms and test yourself at home with the Vitamin D Test. 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