Vitamin D is one of the most important vitamins for the human body. It supports the immune system and is an important building block for numerous processes in the body. One of the most important sources of vitamin D is the sun, which is why it is also known as the sun vitamin. However, vitamin D is not only formed when exposed to sunlight, but is also contained in certain foods. An unbalanced diet, little UV radiation and stress can therefore lead to vitamin D deficiency. But what are the other causes and which symptoms indicate a vitamin D deficiency? What should you look out for? What helps to remedy symptoms? These and other important questions are thoroughly clarified in the following text.
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What are the effects of vitamin D?
Vitamin D is not actually produced by the body on its own. However, as it is already present in the body as the inactive precursor 7-dehydrocholesterol, it does not belong to the group of vitamins, so to speak. Only UV radiation activates it to become an active substance. During the conversion process, it becomes the hormone "calcitriol", which supplies the body with calcium and modulates the immune system, among other things. A vitamin D deficiency can therefore have a negative effect on bones.
In addition to its effect on bones and the immune system, vitamin D also influences brain development and normal muscle function. An undersupply can therefore have a negative effect on the development of babies and embryos. Pregnant women should pay particular attention to taking in enough vitamin D.
The so-called feel-good hormone or serotonin is also regulated by this vitamin. Vitamin D can therefore also indirectly control mood.
What does vitamin D deficiency mean for the bones?
An insufficient intake can have an extremely negative effect on bone health, as vitamin D ensures the absorption of calcium in the intestine and the storage of calcium in the bones. In the event of a vitamin D deficiency, calcium is released from the bone substance and in this way the calcium level in the blood is kept constant. However, this has an extremely negative effect on bone density and can lead to osteoporosis over a long period of time. The bones become more resilient and can break more quickly. It is assumed that vitamin D insufficiency is responsible for a large proportion of hip and femoral neck fractures.
Can vitamin D deficiency be the cause of respiratory infections?
It has been proven that vitamin D deficiency has negative effects on the immune system. As an unstable immune system increases the risk of allergies, respiratory infections also occur more quickly. Vitamin D influences the metabolism as well as the activity and functionality of immune cells.
How important is sunlight?
According to experts, it is not possible to provide the body with sufficient vitamin D from food alone. Only up to 20 % of the vitamin D requirement can be covered by food, while sunlight provides the remaining 80 %. People who rarely spend time outdoors or go out with their bodies completely covered often suffer from vitamin D deficiency. Sunlight stimulates the production of the vitamin D precursor cholecalciferol, which is found in the skin. This is then converted into 25-OH vitamin D3 (calcidiol) and stored. Among other things, the hormone calcitriol ensures the absorption of calcium and phosphate from food and their incorporation into the bones.
Medical advice before taking supplements
It is important to consult a doctor before taking vitamin D supplements. This is because certain medications can increase or impair the effect of vitamin D. These drugs include cortisone, diuretics, sleeping pills and anti-epileptic drugs. Caution is also advised in the case of kidney weakness, a tendency to form calcium-containing kidney stones, parathyroid disease or sarcoidosis. On the other hand, too much calcium in the blood could have a negative effect on the child in the womb. For this reason, pregnant women must be particularly careful and only take appropriate supplements under medical supervision if there is a proven vitamin D deficiency. In this way, calcium levels can be kept under control.
Does it make sense to eat foods containing vitamin D?
Many Germans suffer from vitamin D deficiency¹ because sunlight is too weak in the winter months and many people stay indoors even in summer. As a result, the body has almost no chance of producing and storing vitamin D. Only up to 20% of the daily requirement can be covered by diet, which is nowhere near enough. Nevertheless, a diet rich in vitamin D is useful.
Although most foods contain small amounts of vitamin D, there are foods rich in vitamin D, which almost exclusively include animal foods. These are mainly fatty fish such as herring and kippers, margarine and butter, milk and eggs or egg yolks. Mushrooms and avocados also contain a form of vitamin D, but it is somewhat more difficult for the body to absorb.
However, a sandwich and two eggs are by no means enough. The German Nutrition Society recommends a daily dose of 20 micrograms of vitamin D. To cover the recommended daily dose, you would have to eat 2400 grams of mushrooms, four kilos of beef liver, four kilos of butter or 80 eggs, for example. Consuming such quantities of the respective foods is unrealistic. It is therefore highly unlikely to combat vitamin D deficiency through diet. Without sunlight or appropriate vitamin D supplements, the vitamin D requirement cannot be met.
What are the causes of vitamin D deficiency?
In most cases, insufficient sunlight is the cause of a vitamin D deficiency, while diet plays a rather insignificant role. Skin type, age and the use of sunscreen are also decisive factors. However, according to a study from the USA, vitamin D deficiency is even partly present in summer. This means that some people struggle with a lack of vitamin D despite getting enough sunlight.
There can be numerous reasons for this:
Sun rays One cause of vitamin D deficiency in summer is certainly office work and working indoors in general. People who spend up to 8 hours or more indoors all day are unable to take advantage of the sunlight. So it doesn't matter what time of year it is. The sun in the evening after work is not as strong and is not enough to stimulate the production of the vitamin in the body.
Another factor is long clothing. Short clothing is rarely worn at work and so UV rays are also lost on the way to and from work. Our arms and face are not enough for our body to be able to produce sufficient vitamin D. Only by exposing most of the skin can vitamin D deficiency be counteracted.
Women in particular use numerous creams and lotions with UV protection because they want to prevent skin ageing and protect themselves from sunburn. This is a good thing, as it minimizes the risk of skin cancer. However, such creams hinder the formation of vitamin D in the body and act like long clothing. As almost no UV radiation reaches the body, the production of vitamin D is almost as low as in the cold winter months. People who deliberately expose themselves to the sun for hours on end and use creams with UV protection can therefore also have a vitamin D deficiency. However, due to the risk of skin cancer, sun creams and sunblock should not be completely avoided. The skin still gets at least some sun.
Symptoms of vitamin D deficiency
The symptoms of a vitamin D deficiency are fairly unspecific and could also indicate other diseases. These include
- Tiredness
- sleep disorders
- Muscle weakness
- headaches
- osteoporosis
- bone fractures
- Hair loss
- Increased susceptibility to infections
- Impaired bone mineralization
- Bone pain
- Muscle cramps
- Neuromuscular hyperexcitability
According to the latest study results, the following diseases also occur with an insufficient intake of vitamin D:
- High blood pressure
- heart disease
- diabetes
- depression
- Tuberculosis
- Chronic kidney disease
- cancer
- asthma
- Metabolic diseases
- Multiple sclerosis
These serious illnesses can be linked to a vitamin D deficiency. Several studies have found a link between vitamin D deficiency and diseases such as rheumatism, diabetes and even cancer. More and more people are also suffering from so-called winter depression, which can be a symptom of low vitamin D levels in the blood. Researchers suspect that blood levels of the sun vitamin plummet during the cold season, along with mood. According to studies, people between the ages of 20 and 50 who suffer from sleep disorders have lower levels of vitamin D in their blood.
In addition to zinc and iron deficiency, vitamin D deficiency is also said to affect the health of the hair root. Vitamin D is said to stimulate the growth receptors in the hair roots. Nevertheless, further research is needed to determine whether these diseases are vitamin D deficiency symptoms or whether insufficient vitamin D intake is the cause. It is also still unclear whether an increased intake of vitamin D could help in the fight against such diseases.
Eliminating symptoms of vitamin D deficiency
What to do if you have a vitamin D deficiency? It is actually quite simple to remedy the symptoms of a vitamin D deficiency. Of course, it is important to know the reason for vitamin D insufficiency.
Exposure tothe sun In most cases, vitamin D deficiency is caused by a lack of exposure to the sun. The first step would therefore be to go outside regularly and expose yourself to the sun's rays without protective clothing and sunscreen. The effect of such therapy depends on the strength of the sun's rays. During the colder months and in the later afternoon hours, the sun's rays are not too strong and stimulate vitamin D production more slowly. This means that the time of year and time of day determine the duration of exposure to the sun. Other important factors are age, skin type and latitude. However, caution is advised due to the increased risk of skin cancer. Spending too long in the sun without sun protection could increase this risk. According to the German Nutrition Society, 5 to 10 minutes of sunlight exposure between June and August is necessary for light to very light skin colors in Germany to stimulate good vitamin D production. Between March and May and in September and October, 10 to 20 minutes are required for good vitamin D production. Darker skin types should even stay in the sun for 15 to 25 minutes.
Are sunbeds a good substitute? Although artificial UV radiation contains UV-B rays, sunbeds are still unsuitable for treating vitamin D deficiency. Although UV-B rays can stimulate vitamin D production, the skin receives more UV-A radiation than sunlight. This not only exposes the skin to premature ageing, but also to an increased risk of skin cancer.
Eatingfoods containing vitamin D Food can only cover a small amount of vitamin D requirements. Nevertheless, this is also a method to remedy the symptoms. Regular intake of foods containing the sun vitamin can be useful as a supplement to treatment with sun rays and/or vitamin D supplements.
Vitamin D supplements Especially in winter, supplementation with food supplements is recommended in Germany due to the low sun exposure. Sufficient intake through food is almost impossible to achieve in the long term. Vitamin D supplements are therefore useful if a vitamin D deficiency cannot be compensated for by food and sun exposure. Appropriate supplements are also often used when medication is the cause of a vitamin D deficiency. The family doctor should decide whether and how these should be taken.
Vitamin D deficiency is initially replaced by a higher dose of vitamin D for a week. Once the level has been raised to the desired level, a low maintenance dose is used. After four weeks, the vitamin D levels in the body should be back to normal. A vitamin D test is usually used to check the levels. Many doctors recommend continuing the maintenance dose. If vitamin D deficiency persists, a new dosage is necessary.
But which vitamin D preparation is suitable? There is a wide range of preparations to choose from, which can vary greatly in terms of ingredients and dosage form. Bioavailability plays a decisive role here. This determines the actual absorption and utilization of vitamin D in the body. Poor quality ingredients and the addition of additives could impair the effect.
Vitamin D supplements are also available in various forms, such as drops or tablets. As vitamin D is a fat-soluble vitamin, it is best absorbed by the body when enriched with oil. Always pay attention to the quality of the oil.
Combining vitamin D and vitamin K2 It is usually recommended to take vitamin D together with vitamin K2. But why are vitamin D3 and vitamin K2 such a good team? Taking high doses of vitamin D alone is always associated with certain health risks. Vitamin D increases the concentration of calcium in the blood, which is utilized and deposited in the body as harmful waste products. This can lead to calcification of blood vessels and organs, which can be dangerous.
But this is exactly where vitamin K2 comes into play. The increased calcium level in the blood is not the actual cause of the deposits, but the lack of vitamin K2. Vitamin K2 activates proteins that ensure the utilization of calcium in the blood. As higher doses of the vitamin are therefore common in vitamin D deficiency, these two vitamins should always be taken together. Corresponding preparations are available on the market.
