Vitamin D-Mangel: So wichtig ist das besondere Vitamin

82% of men and 91% of women in Germany suffer from vitamin D deficiency, according to the National Nutrition Survey of the Federal Ministry of Consumer Protection, Nutrition and Agriculture.¹ The sun vitamin is essential. For example, it strengthens the bones and has an influence on metabolism.

Vitamin D: The sun vitamin often has a shadowy existence

Vitamin D is actually not a vitamin at all. It is a group of fat-soluble vitamins such as D2 and D3, which belong to the secosteroids. Vitamin D3 (cholecalciferol) is formed by the skin itself with the help of the sun. This is why it is also called the sun vitamin. And yet vitamin D remained unnoticed for a long time.

It has long been known that vitamin D plays a major role in calcium and bone metabolism. Now it is becoming more and more apparent that vitamin D is involved in numerous other metabolic processes – and all of them are decisive for maintaining the health of the organism.

Vitamin D and the sun

The sun-loving vitamin D likes to be lured out by the sun's rays. Unlike other vitamins, vitamin D not only enters our body through food, but also through the short-wave UV-B rays of sunlight: when these rays penetrate into the epidermis. That is to say the epidermis will produce vitamin D. This is because vitamin D is not only absorbed by the body through food, but also through the short-wave UV-B rays of sunlight. The more sun we "refuel", the more vitamin D is synthesized to replenish our vitamin stores.

Vitamin D during winter

However, especially during the dark season of the year the sun shines only rarely and when it does, it is far too weak. The result: During the sunny months from October to March almost 90% of Germans are undersupplied with vitamin D. The vitamin D reserves built up during the summer empty quickly and are often already exhausted in winter. This is where an extra supply of pure Vitamin D, helps to replenish or continuously refill the reserves.

Even during summer: Vitamin D supply

Actually, vitamin D supply shouldn't be a problem during summer, should it be? The sky is blue, the sun is shining ... But unfortunately, it's not that simple. Many people also have a vitamin D deficiency during summer.

Reasons for a vitamin D deficiency during summer

Not enough sun
In the past, people used to spend more time outside: It was common to work in the fields, to walk (long) distances, to be in nature ... Today we spend so much time in closed (office) rooms, driving a car or taking train and we barely go outside.
Too many clothes
Just sunning your face and your hands isn't enough. You have to expose a lot of skin to stimulate the production of the sun vitamin. Short clothing is a must. If it is colder outside, it is of course difficult to implement.
Sun cream
It is an indispensable remedy against skin diseases and sunburn. But starting from sun protection factor 8, the UV-B rays no longer reach the skin. The body does not produce vitamin D. A dilemma for many. Here it is important to find a balance: Daily, short exposure to the sun, adapted to the skin's own protection time and sun intensity, stimulates the formation of vitamin D without harming the skin.
Pale or dark?
Melanin reduces the production of D3. Light-skinned people produce vitamin D "faster". Dark skinned people have to spend more time in the sun to produce the same amount of vitamin D.
Age
Vitamin D synthesis in older people is reduced by about 75 percent. This is due to the nature of the skin and the dwindling amount of the source substance 7-dehydrocholesterol in the upper layers of the skin.

Vitamin D deficiency and its symptoms

Vitamin D is involved in numerous physical processes. In the long term, a vitamin D deficiency affects almost all areas of the body: Organs, cardiovascular system, cell health, immune system, muscles, nerves. Vitamin D is therefore not only essential for the body, but also for your well-being and vitality.

The signs of vitamin D deficiency are rather unspecific. If you have one or more of the symptoms listed below, ask your doctor for advice: A blood test gives a quick indication of whether there is a vitamin D deficiency. An easy-to-use self-test such as the cerascreen® Vitamin D test also determines and interprets the vitamin D concentration safely and quickly.

Symptoms of vitamin D deficiency

Fatigue
Concentration difficulties
Dizziness, circulatory problems, muscle weakness
Headache
Joint pain
A weak immune system
Bone atrophy and softening
Depression
Dementia

Vitamin D deficiency: risk groups

People who spend little or no time under the sun
Older people 65 years and older -> lower vitamin D synthesis in the skin
Babies – they are not allowed to be under the sun. Today it is common for babies to receive a prophylactic dose of vitamin D in the first few months.
Dark skinned people. Their skin produces only little Vitamin D because of the high content of melanin. In less sunny regions far away from the equator, low levels of vitamin D3 often occur.
Patients with chronic liver or kidney diseases

Vitamin D deficiency in old age

The vitamin D supply in older people is particularly poor. Many elderly people no longer absorb sufficient vital substances and vitamins through their food. In addition, they hardly produce any vitamin D naturally: they rarely go outside to "refuel under the sun", and if they do, the skin is no longer able to synthesize enough vitamin D. In seniors, the production of provitamin D in the epidermis drops drastically. The skin produces only fractions of the vitamin D it needs.

A typical vitamin D deficiency disease in old age is osteomalacia (bone softening with skeletal deformation) and osteoporosis (bone atrophy). An adequate vitamin D supply can promote bone health into old age and reduce the risk of femoral neck fractures, peripheral fractures and vertebral body fractures.²

Many studies show that an increase in vitamin D levels through dietary supplements in seniors has many positive effects, for example on muscle mass, coordination, systolic blood pressure, sugar and fat metabolism and brain performance. Vitamin D is also said to have an anti-inflammatory effect in immunological and allergic diseases. How vitamin D works also depends on other nutrients such as magnesium and vitamin K2. They are important cofactors in vitamin D metabolism.

Vitamin D in food

During winter, when the sun only passes through the sky following a flat trajectory or disappears completely, the Inuit diet brings a lot of vitamin D into the body. The secret of the Arctic tribes: Fatty fish! Go for salmon, herring, mackerel, tuna or – as in grandma's days – cod liver oil. Mushrooms also contain a lot of vitamin D, for example shiitake, mushrooms, porcini mushrooms and chanterelles. These edibles are of course an enrichment to your diet, both for summer and winter.

How much valuable vitamin D does the body need? The German Nutrition Society (Deutsche Gesellschaft für Ernährung e. V.) (DGE) sets a reference value of 20 micrograms of vitamin D per day – in the absence of bodily production.

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^{Photo: istockphoto | max-kegfire, istockphoto | Martinan}
^{1 https://www.bmel.de/DE/Ernaehrung/GesundeErnaehrung/_Texte/NationaleVerzehrsstudie_Zusammenfassung.html (Stand: 24. Oktober 2018)}
^{2 https://www.gesundheitsamt.bremen.de/vitamin_d_mangel_im_alter-4171 (Stand: 24. Oktober 2018)}