Maybe you feel the same way: Especially in autumn and winter you prefer to dress in thick clothes, pull the cap deep in the face, put your hands in warm gloves. Sure, freezing is uncomfortable and unhealthy. However, sun or daylight hardly have a chance to get to the skin. As a result, the body lacks a very important building block for vitamin D synthesis.
Without sunlight no vitamin D.
Let's take a closer look at this mechanism. Actually, the "vitamin D" is not directly a vitamin, but rather a hormone. Up to 90% of the demand is covered by sunlight. By UV radiation, a preform of the vitamin D hormone is formed in the skin. In the liver and kidneys it is transformed into the most biologically active form.
Diet plays a subordinate role in vitamin D. Mostly in offals, oily fish and eggs; lower quantities in milk, butter and cheese. However, a deficiency can not be easily compensated for, because most foods contain too small amounts of the vitamin. Therefore, it can be a good alternative to take targeted vitamin D supplements in the form of tablets, capsules or drops.
Recommendation: 20 micrograms of vitamin D per day
Ideally, the need is mainly met by the sunlight, through which the body itself can produce vitamin D. But: Who thickly packs in the winter, may get too little off. Studies have shown that supplying vitamin D leaves much to be desired in many countries. The German Society recommends 20 micrograms daily (as of 2012). This applies in the event that no endogenous production by UV light takes place. In the US, vitamin D is even added to many foods.
Lack often in the elderly and in northern countries
Particularly affected by the vitamin D deficiency are people who are little in the sunlight or daylight - such as bedridden and sick people. But even those who permanently cover their skin with clothing or consistently protect with sunscreen, are at risk. For older people, another problem is that the body can not produce as much vitamin D itself. Pregnant women and menopausal women are also at greater risk of developing vitamin D deficiency. That's because the hormone balance changes.
By the way: Only if the sun is high enough, it works with the vitamin D formation. In northern countries this is sometimes not even in the winter at lunchtime (and that applies to certain parts of Germany!).
Varied effects of vitamin D.
But why is vitamin D so important at all? There are several reasons for this, because its effect is manifold. Or rather, let's say that if there is a problem, problems can arise at different levels. The Ärzteblatt said in 2013 that symptoms of severe vitamin D deficiency could affect the whole body. For example, sufferers suffered from fatigue, depression, knee and back pain, sleep disorders and skin problems.
Important for bone health
Best known is that a vitamin D deficiency harms the bones, deforms them or causes skeletal pain. In 2012, the German Society for Nutrition (DGE) rated the thesis that a sufficiently high vitamin D level lowered the bone fracture risk as "convincing".
A deficit causes sometimes - especially in older people - a bone loss (osteoporosis), a bone softening (osteomalacia) or muscle weakness. In infants or children, it can cause rickets, which can lead to skeletal deformities.
According to the DGE, there are plenty of high quality studies that confirm these effects of vitamin D deficiency. The Institute of Medicine in the USA also concludes that there is a clear link between bone disease and insufficient vitamin D supply.
Vitamin D may lower high blood pressure
Another field where Vitamin D scores, is the cardiovascular system. Accordingly, vitamin D probably has a certain influence on the blood pressure. It is interesting that this is not true for people with normal blood pressure, but for those with high blood pressure. Several studies have shown that the administration of vitamin D leads to an existing hypertension decreases.
Apart from that, the risk of coronary heart disease may be reduced. Impressive is a study of Danish researchers over a period of almost 30 years. More than 10,000 subjects took part. The result: High vitamin D levels significantly reduced the likelihood of dying from a heart attack.
Maybe also protection against diabetes type 2
Apparently, vitamin D also has a positive effect on the blood sugar level and the effect of insulin. While a low vitamin D level increases the likelihood of developing type 2 diabetes (so-called "adult onset diabetes", which affects more and more young people), a good supply of vitamin should be beneficial. This, in turn, benefits the heart and circulatory system, as diabetes is a risk factor that causes the arteries to "calcify" (arteriosclerosis) and heart attacks.
Amazing results on the effect on bronchial asthma
According to surveys, asthmatics also benefit if they regularly give their body a good dose of vitamin D. Studies have shown that too low vitamin D levels significantly increase the risk of disease. This was confirmed by a study with about 18,900 participants in the US. The asthma risk quintupled in subjects with a lack of vitamin D.
The assessment was just as promising in the renowned magazine "Cochrane Database of Systematic Reviews". The scientists of the Queen Mary University of London evaluated several studies. These were mainly mild to moderate asthma conditions - both in children and adults.
The surveys included a total of more than 1,000 subjects. The stronger asthma attacks (those requiring emergency treatment or hospitalization) decreased by several percentage points. In addition, the number of attacks requiring Cortisone delivery decreased. Of great importance is also the following finding: There were no significant side effects.
Body's defenses could be strengthened
Vitamin D probably also has an influence on general infections of the upper respiratory tract. According to studies, such diseases are more common with a reduced vitamin D level. This makes it clear that this vitamin is a great help for the immune system. Apparently, the body is thus more able to fight viruses, fungi and bacteria. Therefore, it is important that the body has enough vitamin D available.
Not very clear results in cancer
Other, dreaded attackers are also intimidated by vitamin D: cancer cells. However, there are contradictory studies. There are good results on the influence of vitamin D - combined with Calcium - on colon cancer. Here a high level of vitamin D may lower the risk.
Other surveys reported similar results for breast, stomach, ovarian and kidney cancer. In other studies, however, no anti-cancer effects could be detected.
In animal experiments, protection against Alzheimer's and Parkinson's
At least in experiments with roundworms (which have proven to be very suitable for research on aging), it has been shown that vitamin D protects against diseases that accumulate in old age - for example, Alzheimer's disease or Parkinson's disease. Researchers at an institute in California discovered that vitamin D inhibits the process of damaging important proteins, causing them to clump together and deposit in the brain.
Of course, threadworms are not comparable to humans as a whole. Nevertheless, these results give cause for optimism.
Possible effects on mood and tiredness
Some studies suggest that vitamin D levels are linked to depression, fatigue and fatigue. Thus, a vitamin D deficiency could increase the risk of developing depression in old age.
In other surveys, vitamin D had no effect on mood and mental health. However, this may also be due to the way the examinations were designed. Maybe the dose was not enough or the observation period was too short.
Conclusion: Vitamin D preparations with proper use quite useful
So we've seen that "sun vitamin" is especially important for the stability of our bones by providing them with calcium. In addition, it seems to slow down inflammatory reactions and autoimmune processes. It could also have a positive influence on degenerative and even malignant diseases.
However, vitamin D is also not a panacea, as often propagated; On the other hand, the arbitrary and improper intake of vitamin supplements also carries risks. Because vitamin D is fat-soluble, which in turn means that the body can store and accumulate it. Excessively high doses can therefore cause considerable damage.
So if you want to supplement your vitamin D level with appropriate preparations, please pay attention to the dosage recommendations. A serious provider can not hurt either.We can recommend this provider, because we know him well.
Author: Dr. med. Jörg Zorn
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All questions about Vitamin D.