Vitamin D is one of the fat-soluble vitamins and is also understood as a hormone. Sunlight is the most important source of vitamin D for us humans. This is why vitamin D deficiency is more common in many people, especially in winter. However, the right diet can help here.
In the following article you will learn more about the main functions, as well as the consequences and causes of vitamin D deficiency symptoms. In particular, the topic of vitamin D deficiency and nutrition should be addressed. In the following, you will receive valuable tips on how to successfully treat a vitamin D deficiency.
the essentials in brief
- Vitamin D deficiency is widespread. In particular, many people experience this during the winter months due to less sun exposure. The main causes of vitamin D deficiency are an unbalanced diet, office work and age.
- If left untreated, a vitamin D deficiency can have serious long-term consequences. For example, this can lead to softening of the bones, also known as osteomalacia.
- The good news is that vitamin D deficiency is easily curable. A good sunbath is often enough for this, but you can also replenish your vitamin D stores with the right foods. You can find out exactly which foods are involved in this article in this article.
Compensate for vitamin D deficiency through proper nutrition: What you should know
In winter, the opportunity to soak up the sun is limited. However, sunlight is our most important source of vitamin D. A German medical study from 2015 showed that at least 30 percent of German subjects had too little vitamin D in their blood in the months of October to April.(1)
Accordingly, someone who lives in northern Germany, for example, has no chance of producing sufficient vitamin D due to the low solar radiation in the winter months.
When does vitamin D deficiency occur?
Since, as already mentioned, sunlight is the most important source of vitamin D, vitamin D deficiency occurs most frequently in the winter months. However, there are also many people who also have such a deficiency in the summer months. This is due to a number of factors, the main ones we have listed below.
- Unbalanced diet: In addition to sunlight, another essential source of vitamin D is food. You can find the vitamin in a wide variety of foods, such as avocados, eggs, cheese, etc. However, if you eat a relatively unbalanced diet and do not eat any of these foods in sufficient quantities, your eating habits can quickly lead to a vitamin D deficiency.
- Work in the office: Although the sun shines sufficiently in most regions of Germany in summer, many do not have the opportunity to use these hours of sunshine accordingly. Because most people spend at least 8 to 10 hours indoors, at least on weekdays. Accordingly, it is very difficult to soak up sufficient sunlight alongside such a job.
- Age: Another reason for a vitamin D deficiency is our natural aging process. Our body can produce less vitamin D as we age. In addition, the skin becomes thinner as we age, which also affects the production of vitamin D. Thus, older people are potentially more at risk of being vitamin D deficient than others.(2)
How do I know that I have a vitamin D deficiency?
There are various symptoms that can occur with a vitamin D deficiency. However, such signs usually only become apparent in the event of a long-term deficiency and often cannot be immediately attributed to a vitamin D deficiency. To be sure whether you have a vitamin D deficiency or not, you need to take a blood test at the doctor's. Only this brings you explicit certainty.
Such a blood test can be carried out by the family doctor, but there are now also self-tests from the pharmacy, where a few drops of blood are sent to the laboratory on a test strip and the evaluation can then be viewed online.
If you are healthy, you don't have to take a blood test, but you should take vitamin D every day in winter, because the sun's rays are then not enough, even for healthy people. Chronically ill people should have a blood test during the winter months.
If you suspect that you are suffering from a vitamin D deficiency, you should definitely carry out such a test. Even if you feel generally healthy, but actually have a relatively unbalanced diet and don’t otherwise expose yourself to the sun much, you should do such a test to be on the safe side.
The potentially serious consequences of long-term vitamin D deficiency show why this is so important. For example, it can lead to softening of the bones (osteomalacia).(3)
What does the body need vitamin D for?
Basically, vitamin D is needed for metabolism, bone formation and the immune system.
Vitamin D essentially supports the mineralization of the bones and promotes the absorption of calcium, magnesium and phosphates from food.
The vitamin also plays an important role in muscle metabolism and defense against infection. This means that the vitamin makes a significant contribution to strengthening the immune system.
A vitamin D deficiency thus triggers various diseases, especially in the long term, and can also have a significant impact on mood.
What are the consequences of a vitamin D deficiency?
As already mentioned, vitamin D in our body is particularly important for our metabolism, our bone structure and our immune system. Accordingly, a long-term deficiency of vitamin D can have serious consequences.
A potentially serious condition is softening of the bones, also known as osteomalacia. This is very painful and occurs especially in older people.
But in general, a vitamin D deficiency can manifest itself through bone pain. Other possible effects are also disturbances in the calcium and phosphate metabolism, respiratory infections, depression and mood swings.
Can you compensate for a vitamin D deficiency through proper nutrition?
Basically, sunlight is considered the first and most important source of absorption of the vitamin. This covers 80 to 90 percent of our vitamin D requirements. This is the fastest way to absorb and store vitamin D.
A balanced diet is one of the most important sources, after sunlight, to replenish your vitamin D stores. (Image source: unsplash / Dan Gold)
However, if this is not possible for you, for whatever reason, it is also possible to compensate for a vitamin D deficiency through food to a limited extent. The focus here is on the word conditional.
Depending on the person and the individual previous illnesses and needs, a vitamin D deficiency manifests itself differently and must therefore be treated differently. For example, a slight vitamin D deficiency can be compensated for with a balanced diet and the right foods.
In principle, however, you should primarily listen to the instructions of your doctor in the event of a deficiency. If you are prescribed to take certain preparations here, you should also take them accordingly and change your diet as well.
How Much Vitamin D Do I Need?
An exact requirement value is not known. However, there is an estimate by the DGE (German Society for Nutrition) for an appropriate supply in the absence of the body's own formation.
You should note here that this is a guideline in the absence of endogenous synthesis . This means that this value applies to people who cannot produce any vitamin D themselves, so it stands for the general need for vitamin D. This value is expressed in micrograms (µg).
In addition to the body's own production, the vitamin can be ingested through food in small amounts, around 10 to 20 percent of the estimated value.
You can see how much vitamin D a person needs from the following table:
|Old||Vitamin D requirement in the absence of endogenous synthesis|
|Infant (0-12 months)||10 µg/day|
|child (1-15 years)||20 µg/day|
|Teenagers and adults (from 15 years)||20 µg/day|
In which foods can I find vitamin D?
Vitamin D is not available in high levels in many foods. However, since it is one of the fat-soluble vitamins, it is mostly found in high-fat foods of animal origin. These include in particular fatty sea fish such as salmon, herring or mackerel.
As already mentioned - in addition to being produced by the body, small amounts of vitamin D, around 10 to 20 percent of the estimated value, can be ingested through food.
The following list shows which foods are particularly rich in vitamin D:
|Groceries||vitamin D content|
|Herring, 100 g||25 µg|
|Salmon, 100g||16 µg|
|Avocado, 100g||6 µg|
|mushrooms, 100 g||1.9 µg|
|Emmental, 60 g||0.33 µg|
|whole milk, 200 ml||0.18µg|
|butter, 10 g||0.13 µg|
|Beef liver, 100 g||1.9µg|
Does a vegetarian or vegan diet cause a vitamin D deficiency?
Vitamin D is already found in high levels in limited foods. Accordingly, vitamin D intake through food is particularly difficult in a vegetarian or vegan diet.
Two English studies from 2013 and 2003 showed that vegetarians and vegans have lower intakes of vitamin D compared to the general population.(4,5)
In particular, however, people with a vegan diet show a year-round, comparatively high vitamin D deficiency. In addition, in two studies from 2011 and 2009, these people had a lower bone mineral density compared to vegetarian and mixed diet test people.(6,7)
Accordingly, it is recommended, especially for vegans, but also vegetarians, to spend more time in the sun in order to cover their vitamin D needs as best as possible.
Can I compensate for a vitamin D deficiency by sunbathing?
The clear answer to this answer is yes. In any case, sunlight is the main source of vitamin D intake and basically covers 80 to 90 percent of our vitamin D requirements.
In order for the body to be able to produce enough of the vitamin when sunbathing, a short stay in the sun is sufficient.
This is recommended by the Federal Office for Radiation Protection. You should aim for 10 to 20 minutes here. After that, at the latest, you should smear yourself with an appropriate sunscreen.
It's important not to wear sunscreen during this time, as it may inhibit vitamin D production. This does not mean that sun creams and similar products are generally discouraged, as they provide important protection. However, you should make sure you can get enough vitamin D from time to time, although this is only possible without such products.
Is a vitamin D overdose dangerous?
As harmful as a vitamin D deficiency can be, an overdose of the vitamin can be just as dangerous.
There are now countless vitamin D preparations that can be purchased freely. However, you should be careful not to risk an overdose. (Image source: unsplash / Adam Nieścioruk)
The Medicines Commission of the German Medical Association (AkdÄ) warns against taking vitamin D preparations and the like. on your own hand. Because as much as you want to avoid a vitamin D deficiency, you should also pay attention to avoiding an overdose.
Before taking any vitamin D supplements, you should always consult your doctor first.
An overdose of vitamin D can lead to hypovitaminosis, i.e. an overdose of vitamins. This often manifests itself in the short term as headaches, tiredness, nausea, diarrhea or severe thirst.(8)
In the long term, however, it can also have more serious consequences. For example, excess calcium can build up in the kidneys and blood vessels, leading to serious kidney disease. Symptoms range from kidney stones to kidney failure.(9)
What alternatives are there to combat vitamin D deficiency?
In addition to sunlight and food as the most important sources of vitamin D, there are also two other alternatives for taking vitamin D. These are vitamin D deficiency therapy and vitamin D preparations, which will be presented in more detail below.
- Therapy : If there is a vitamin D deficiency, the doctor often prescribes therapy for the person concerned. This involves taking certain vitamin D preparations over time to compensate for the deficiency. The therapies differ depending on the dosages to be taken and the period of time.
- Preparations : Vitamin D can now be purchased in a wide variety of forms. The vitamin is primarily available as drops, capsules or tablets. There are also combination variants, which contain vitamin D as well as other vitamins or nutrients.
Vitamin D deficiency is one of the most widespread deficiency symptoms nowadays. However, this can be cured quite easily, in addition to taking various preparations, this also includes a balanced diet and sufficient sunlight.
However, to be on the safe side, you should always have a blood test done to make sure whether there is a vitamin D deficiency or not. Because taking vitamin D supplements on your own can be dangerous.
- The aim of the present study, the 'German Health Interview and Examination Survey for Adults' (DEGS1), is to give an overview of the current situation of vitamin D status and important determinants in the resident population 18–79 years of age in Germany . This comprises the analysis of serum 25(OH)D levels overall and according to sex, age, season and latitude of residence as well as the calculation of serum 25(OH)D percentile values according to month of examination.
- This report reviews evidence on disorders related to inadequate vitamin D repletion in older people. Vitamin D is as essential for bone health in adults as in children, preventing osteomalacia and muscle weakness and protecting against falls and low-impact fractures.
- The current value of vitamin D and its importance for bones and other body cells are demonstrated.
- The objective is to compare relative weight, weight loss efforts and nutrient intakes among similarly health-conscious vegetarian, past vegetarian and nonvegetarian premenopausal women.
- The objective is to describe the lifestyle characteristics and nutrient intakes of the Oxford cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC).
- Vegetarians and vegans exclude certain food sources of vitamin D from their diet, but it is not clear to what extent this affects plasma concentrations of 25-hydroxyvitamin D (25(OH)D). The objective was to investigate differences in vitamin D intake and plasma concentrations of 25(OH)D among meat eaters, fish eaters, vegetarians and vegans.
- Vegans and other vegetarians who limit their intake of animal products may be at greater risk of vitamin D deficiency than nonvegetarians, because foods providing the highest amount of vitamin D per gram naturally are all from animal sources, and fortification with vitamin D currently occurs in few foods.
- A literature search was carried out in PubMed for cases reporting vitamin D intoxication and overdose. Thirteen articles were included in this review. Intoxication was severe in the reported cases. Patients presented with serum vitamin D concentrations ranging between 150 and 1220 ng/mL and serum calcium concentrations between 11.1 and 23.1 mg/dL.
- Abnormalities in vitamin D metabolism play a major role in the pathogenesis of secondary hyperparathyroidism in chronic kidney disease. The gradual and progressive decline in 1,25-dihydroxyvitamin D in the course of chronic kidney disease is the result of several mechanisms that limit the ability of the failing kidney to maintain the levels of 1,25-dihydroxyvitamin D despite increasing levels of parathyroid hormone . Recent observations have indicated that chronic kidney disease seems to be associated with a high incidence of nutritional vitamin D insufficiency or deficiency as manifested by decreased levels of 25-hydroxyvitamin D.