Why do we lack vitamin D, especially in winter?
Unfortunately, those who live in the north hardly have the opportunity to produce enough vitamin D in the winter months. At least a third of Germans have too little vitamin D in their blood during the autumn and winter months. However, a long-term deficiency can be harmful to health, because the body needs the vitamin to incorporate calcium from food into bones and teeth.
What are the consequences of a deficiency?
A lack of vitamin D can have serious consequences such as damage to the bones. As a result, bone density decreases, and a deficiency in older people promotes osteoporosis. In addition, there is a higher likelihood of respiratory infections, muscle weakness, mood swings and even depression. In infants and children, on the other hand, a severe vitamin D deficiency can lead to rickets and thus to permanent deformities of the skeleton.
How do you prevent a deficiency?
The best way to counteract a vitamin deficiency is to build up reserves during the “lighter” months – the body stores these in fat and muscle tissue. The Robert Koch Institute (RKI) recommends exposing your face, hands and arms to the sun without sunscreen and uncovered about two to three times a week between March and October. According to the Federal Office for Radiation Protection, sufficient vitamin D production takes half the time that sunburn would develop without protection. For example, if you have light skin (skin type II), you should stay in the sun without protection for a maximum of 20 minutes with a UV index of 7 (which roughly corresponds to solar radiation in summer). So that enough vitamin D is formed, ten minutes is enough.
This vitamin D supply is sometimes sufficient to get through the winter without any deficiency symptoms. The body also produces some vitamin D in the colder months, for example when you go for a walk outside with your face open and without gloves. Contrary to some assumptions, however, daylight lamps are not an alternative because they usually have a UV filter – and it is the UV component of the light that stimulates the body’s own vitamin D production.
Part of the need can also be covered through nutrition – but that is only about ten to 20 percent. Anyone who has foods such as eggs, fatty fish (e.g. salmon or herring) and certain dairy products such as cheese or butter on their menu more often will at least get the most out of this. For years, the avocado was also considered a good source of vitamin D, but more recent measurements refute this.
When are vitamin D supplements useful?
It can therefore make sense for some people to also cover their vitamin D requirements with tablets. Older people in particular are among the risk groups that often suffer from a deficiency. On the one hand, this is due to the fact that the skin’s ability to produce vitamin D decreases with age. In addition, older people tend to spend less time outdoors because, for example, they need care or are not very mobile. For this reason, chronically ill people are more likely to suffer from a deficiency, as are people who only go outside with their bodies completely covered. In addition, dark-skinned people belong to the risk groups because the higher melanin content of their skin shields UV-B radiation more effectively. Finally, supplementary preparations are also suitable for smokers, as a lack of vitamin D may impair lung function.
What is there to consider and how much should you take?
However, the following applies: Before taking special vitamin D preparations, you should definitely consult a doctor and also have your vitamin D status checked. In justified cases, the statutory health insurance companies cover the costs of the test, otherwise around 30 euros are due for it.
How high a dose of vitamin D is ultimately to be dosed depends on several factors: These include body size, age and possible previous illnesses. Be careful with offers on the Internet, because some preparations with very high dosages per capsule are offered here. However, an overdose is also harmful because vitamin D is fat-soluble and accumulates in the body – too much causes excessive calcium levels over time, which in turn can cause abdominal cramps and nausea and, in severe cases, even cardiac arrhythmias and kidney damage. The Federal Institute for Risk Assessment (BfR) also warns of the dangerous consequences of excessive vitamin D intake: It therefore recommends a maximum daily dose of 20 micrograms, which corresponds to 800 IU (international units). In the best case, the whole thing is taken under medical supervision.
CONCLUSION:
Because the body needs sunlight to produce vitamin D, many people are deficient in winter. Among other things, it can increase the susceptibility to infections and at the same time have a negative impact on bone density. During the cold season, it is therefore advisable to go unprotected in the sun as often as possible and to eat more eggs, fatty fish and certain dairy products such as cheese. In the case of a severe deficiency, additional vitamin D supplements can also help. |Text: Vera Mergle