The advertising constantly suggests that a vitamin D deficiency is present in the majority of the population without such a deficiency actually being proven. An undersupply is discussed in public in connection with cardiovascular diseases, high blood pressure, a higher risk of cancer, rheumatism or diabetes mellitus (type 1).
A majority of the healthy German population is not thought to have a vitamin D deficiency. However, according to the nutrition report, the vitamin D supply of the German population is generally insufficient. Approximately 1/3 are insufficiently supplied and only scarcely 40 % are sufficient. Above all, the proportion of inadequately cared for women increases with increasing age. Scientific studies have shown, for example, that a good supply of vitamin D can protect older people from bone fractures.
With the help of a few tricks, however, vitamin D intake can be improved through nutrition and the body’s own formation. However, there are also situations or risk groups (see below) in which the use of vitamin D products makes sense.
However, advertising claims that an improved supply of vitamin D can prevent diseases such as cancer, diabetes, cardiovascular diseases, diseases of the nervous system or infections have not been scientifically proven.
For whom is vitamin D useful?
The intake of vitamin D products (i.e. an additional intake in addition to nutrition and the body’s own formation) is only recommended if an inadequate supply has been proven and a targeted improvement in the supply can neither be achieved through a more favourable food selection (see below) nor through the body’s own formation of vitamin D by means of increased exposure to the sun. They belong to one of the risk groups in which the use of vitamin D products can be useful if you:
- are older than 70 years, because with age the self-production of vitamin D decreases. Why older women in particular are more likely to be undersupplied than older men has not yet been clarified. Causes could be the naturally higher body fat portion of women, the avoidance of sunlight by visiting shady places, the stronger covering of the body outside, the more frequent use of sunscreens and skin creams with sun protection factor or also the insufficient consumption of vitamin D-rich food.
- belong to the very elderly seniors: Supplementation is important for them, especially if their mobility is limited and they are no longer able to stay in the sun sufficiently, e.g. if they live in a care facility. According to the latest studies from April 2018, additional vitamin D and calcium are unlikely to provide protection against falls of the very elderly.
- The sun’s UVB rays are held off more strongly by the increased melanin content in the skin and therefore not enough vitamin D is produced in the skin.
- If you always cover most body parts including arms and legs with clothing and never expose them to the sun.
- Infants can be affected by vitamin D deficiency as the vitamin D content in breast milk is low and the baby’s skin should not be exposed to the sun due to the lack of a protective mechanism.
Therefore, as part of the general precaution, your paediatrician will prescribe special vitamin D preparations (medicines).
What should I pay attention to when using vitamin D?
If you want to take vitamin D products: According to an expert commission (BVL/BfArM), products can only be regarded as food supplements up to a daily dose of 20 micrograms of vitamin D (= 800 i.E.). However, their use should also be discussed with your doctor beforehand in order to clarify the need.
In no case should more than 100 micrograms (=4000 i.E.) per day be ingested in total (including food). In principle, the dosage specified by the manufacturer should not be exceeded under any circumstances: Headaches, nausea and loss of appetite, in the worst case even kidney calcification and kidney stones could be the result. Especially with significantly higher doses of products from the Internet, serious damage to health occurs again and again.
Interactions with drugs are possible: Caution is advised when taking cardiac glycosides, for example. If you need to take medication, you should discuss it with your doctor or pharmacist before purchasing a dietary supplement. He can tell you if there is a risk of interactions and how you can avoid them by taking them at regular intervals.
These vitamin D compounds are approved in food supplements in Germany and other EU countries (according to EU Directive 2002/46/EC, Annex II (version of 05.07.2017)):
- Cholecalciferol (D3)
- Ergocalciferol (D2)
Food supplements are offered with vitamin D3 and vitamin D2. Vitamin D2 is obtained from yeast by UV radiation of ergosterol (vitamin precursor). It is therefore vegan, but is not so well absorbed by the body. Vitamin D3 for food supplements is usually obtained from wool fat (lanolin). In vegan products, which are offered with vitamin D3, the vitamin comes from certain lichens.