Vitamin D Deficiency: Symptoms And Consequences

Vitamin D can be produced by the body itself. However, this requires sufficient sunlight. In central and northern Europe, however, the sun’s rays are usually not sufficient – and the body cannot produce the vitamin D quantities that are so urgently needed.

Vitamin D deficiency: first non-specific symptoms

Vitamin D deficiency can lead to very different symptoms. Most officials claim that vitamin D deficiency actually mainly affects the skeleton, which can be recognized by poor bone health. However, anyone who already suffers from skeletal pain and deformed bones not only has a particularly extreme vitamin D deficiency but has usually had it for a long time.

Better not to let it get that far in the first place. Therefore, it would not be bad if one were to pay attention to the first signs of a vitamin D deficiency. Symptoms can be very unspecific, such as e.g.:

Vitamin D deficiency: the symptoms

  • Frequent infections
  • Poor wound healing
  • General fatigue
  • bone and back pain
  • Chronic bad mood
  • depressions
  • sleep problems
  • declining physical and mental performance
  • bad complexion
  • poor wound healing
  • fibromyalgia
  • diabetes
  • asthma
  • periodontitis
  • Cancer
  • osteoporosis
  • autism
  • ADHD

Of course, the symptoms or diseases mentioned can also have other causes – and of course, taking vitamin D alone does not cure all diseases. However, a vitamin D deficiency can often be an important contributory cause. If the deficiency is corrected, problems such as autism and ADHD often improve – and serious illnesses respond better to therapies.

You should therefore always have your vitamin D level checked – whether you have non-specific symptoms or specific chronic diseases – and, if necessary, remedy a vitamin D deficiency immediately.

Below we discuss some of the mentioned symptoms or consequences of vitamin D deficiency in detail.

Frequent infections

One of vitamin D’s main roles is to support and regulate the immune system. The symptoms of vitamin D deficiency therefore include increased susceptibility to infections. Bacteria and viruses now have an easier game and those affected constantly suffer from some kind of infection, most of the respiratory tract. So if you’re catching every cold that’s going around, think about your vitamin D levels.

Some large observational studies are already showing the link between vitamin D deficiency and common respiratory infections, such as the common cold, bronchitis, and pneumonia.

Further studies found that taking 4,000 IU of vitamin D daily can significantly reduce the risk of respiratory infections. Of course, it is important to have your vitamin D levels checked first. Because vitamin D intake can only bring about an improvement in the condition of those people who previously had a corresponding deficiency.

Poor wound healing

A weak immune system can also show up in poorly healing wounds, e.g. B. after injuries or operations. Here, too, the vitamin D level should be considered. Because vitamin D is directly involved in wound healing and influences – e.g. According to a study from September 2016 – several processes are required for rapid wound healing:

It activates the so-called TGFβ1, a connective tissue growth factor, and the so-called fibronectin, a protein responsible for tissue repair. Vitamin D also increases collagen production, fibroblast migration, and myofibroblast formation. Myofibroblasts are special cells that play an important role in wound healing. In addition, vitamin D is considered an anti-inflammatory vitamin, which is also beneficial for good wound healing.

Vitamin D supplementation can therefore be an important step in improving previously poor wound healing and regeneration. Here, too, it is important that vitamin D can of course only improve wound healing in people who have previously suffered from a vitamin D deficiency.


Vitamin D deficiency is also a possible cause of chronic fatigue and fatigue. For example, a case report (December 2010) involved a patient with chronic daytime sleepiness. She was found to have an extreme vitamin D deficiency (her level was only 5.9 ng/ml, a healthy vitamin D level is 40 ng/ml), unfortunately, the official level is already 20 ng/ml sufficient.

Many people are therefore often told after a vitamin D test: Everything is fine – even if the patient is anything but fine. On the other hand, if they had vitamin D levels above 40 ng/ml, they would actually be fine in many cases. Therefore, chronic symptoms can develop even with vitamin D levels that are significantly higher than those of the patient described.

This now took vitamin D as a dietary supplement. Her vitamin D levels rose to 39 ng/ml and her symptoms disappeared.

Another study found that women with vitamin D levels below 29 ng/ml reported symptoms such as fatigue more often than women with vitamin D levels above 30 ng/ml.

Chronic pain

Back pain can also be a symptom of vitamin D deficiency. Large observational studies have found at least one clear link between vitamin D deficiency and back pain. Most people who suffered from back pain were also vitamin D deficient.

Since a vitamin D deficiency has been shown to impair bone metabolism and muscle function, study results of this type are not a great surprise. Weakened muscles and diseased bones can, of course, easily lead to back pain, but also to other chronic pain conditions, such as those caused by B. be observed in fibromyalgia.

A 2010 study of 276 patients found that people with vitamin D deficiency were twice as likely to develop chronic pain in their legs, ribs, and joints as those with healthy vitamin D levels – had values.

A vitamin D deficiency is now observed in many complaints. It is therefore much more interesting to ask whether vitamin D administration can improve the symptoms again. In the case of pain conditions, there are at least two studies showing that high doses of vitamin D (single administration of 150,000 or 300,000 IU) can reduce the pain (if the affected person has previously taken a vitamin D lacking).

Bad mood and depression

A chronically depressed mood can also be a symptom of vitamin D deficiency. Vitamin D deficiency is often associated with depression, particularly in older patients. If you have an elderly family member who has been prescribed antidepressants, you can also recommend that their family doctor check their vitamin D levels (if they haven’t already).

This connection has also been shown in younger women suffering from PCOS (polycystic ovarian syndrome, a common hormone disorder). The lower their vitamin D levels, the more likely they were to develop depression.

Some studies examining whether vitamin D supplements could alleviate depression found no effect. However, this could be due to the fact that very low doses of vitamin D were used, which can then actually have no effect. Other studies were not carried out long enough so no effect can be expected here either.

On the other hand, studies conducted over a year with sufficiently high doses of vitamin D (20,000 to 40,000 IU per week), for example, clearly showed that depression improved.

Chronic diseases: often the result of vitamin D deficiency

If a vitamin D deficiency persists for years, completely different symptoms can develop as a result, namely specific diseases. There are now studies on almost every symptom that show that in the vast majority of cases there is always a vitamin D deficiency – no matter what disease you are suffering from.

In addition, we know that diseases can not only develop more quickly due to a vitamin D deficiency but that they often become more serious if the patient suffers from a vitamin D deficiency. Conversely, this means that vitamin D intake in diseases weakens their course. For example, a good supply of vitamin D in ulcerative colitis – a chronic inflammatory bowel disease (IBD) – can prevent further flare-ups (vitamin D), in neurodermatitis, the vitamin noticeably improves the complexion (vitamin D in ulcerative colitis) and in diabetes, vitamin D has a positive effect in several ways:

Vitamin D deficiency can cause diabetes

Vitamin D deficiency has an enormous impact on the risk of diabetes and is an even greater risk factor than being overweight. It has long been known that overweight diabetics can massively improve their diabetes if not even cure it if they lose weight. In 2015, however, researchers at the Spanish University of Malaga showed that a good vitamin D supply can protect against diabetes even better than reducing obesity.

Since a vitamin D deficiency also means that the body stores fat much more easily and it is much more difficult for people to lose weight, a good supply of vitamin D could reduce the risk of diabetes twice as well: firstly via the preventive effect of the Vitamins and on the other hand about the vitamin D-related facilitated weight loss.

Polyneuropathy is a chronic nervous condition affecting the nerves in the arms and legs.

Vitamin D deficiency: Periodontitis and gingivitis

Chronic gum disease is associated with inflamed gums that bleed quickly, periodontitis, and can not only be a symptom of a vitamin C deficiency, but also a sign of a vitamin D deficiency.

Taking vitamin D can have a beneficial effect on gum problems. Vitamin D stimulates the body’s own production of so-called defensins and cathelicidins. These are endogenous antimicrobial substances that act against harmful bacteria on the mucous membrane surfaces – and thus also on the gums – and can thus protect against gum problems.

Vitamin D also has an anti-inflammatory effect and also protects the jawbone from damage to the periodontium caused by periodontitis.

Vitamin D deficiency: cardiovascular disease and dementia

Problems with the cardiovascular system can also be symptoms of vitamin D deficiency. Various studies have shown that low levels of vitamin D (below 30 ng/mL) are associated with a higher risk of developing high blood pressure.

In addition, it is suspected that cholesterol levels are also significantly more closely related to vitamin D levels than previously thought.

Those who were not well supplied with vitamin D as a child are more likely to develop arteriosclerosis later in life than people who were in the sun a lot in their childhood and therefore also had plenty of vitamin D available.

In the case of circulatory and vascular problems, brain health is always affected.

Vitamin D deficiency can cause cancer

Cancer is also more likely to develop if the person is vitamin D deficient. Researchers at Georgetown University Medical Center in Washington DC discovered that women who were high in vitamin D were less likely to develop breast cancer than women with low vitamin D levels.

And even if a woman already had breast cancer, her cancer would grow more slowly if she had healthy levels of vitamin D.

Multiple sclerosis due to vitamin D deficiency?

It is often already decided in the womb which disease one will be particularly susceptible to later in life. For example, if the mother smokes, the risk of her children later being infertile increases. Does the mother take medication during pregnancy, e.g. B. paracetamol, then this can increase the risk of autism in their children?

But vitamin D also helps later in the prevention and treatment of multiple sclerosis. In a 2006 study, researchers showed that increasing vitamin D levels reduced the risk of developing MS (21). And in 2010, a study by the University of Toronto ( 22) found that taking 14,000 IU per day in existing MS could prevent relapses. However, taking only 4,000 IU showed no corresponding effect.

Vitamin D deficiency causes bone loss/osteoporosis

Osteoporosis is of course THE disease that almost everyone immediately thinks of as vitamin D. The vitamin even has a firm place in conventional osteoporosis therapy. Because vitamin D plays a key role in bone metabolism and also enables the absorption of the bone mineral calcium in the intestine.

Unfortunately, the prescribed doses of vitamin D are usually far too low. Generally, supplements that provide 800 to 1000 IU of vitamin D are prescribed. The reason is often that one fears hypercalcemia, i.e. an excessively high calcium level in the blood, which in turn could become problematic for the kidneys and also the heart.

However, this problem arises in particular because older people with osteoporosis are usually recommended far too much calcium. Doctors still believe that calcium is the be-all and end-all for the bones and therefore recommend plentiful consumption of dairy products and, not infrequently, calcium supplements. Instead, sufficiently high doses of vitamin D in combination with magnesium, vitamin K2, and plenty of exercise are much more important than calcium for good bone health.

In any case, it is known from observational studies that a vitamin D deficiency contributes to bone loss, particularly in postmenopausal women. Study results on the effect of vitamin D administration on bone density are inconsistent, mostly because the vitamin D doses given are far too low.

Limescale due to vitamin D deficiency

Even the calcified shoulder can indicate a vitamin D deficiency. In the case of a calcified shoulder, painful calcification occurs in the attachment area of the shoulder tendons. If enough vitamin D were available – the vitamin is known to be involved in calcium metabolism – the risk of a calcified shoulder would drop considerably. Of course, not only a vitamin D deficiency is responsible for the calcified shoulder, but such a deficiency – with an existing calcified shoulder – can delay the healing process.

Autism and ADHD due to vitamin D deficiency

In children, vital substance deficiencies can also show up in behavioral problems. If it is just a lack of vital substances (not just vitamin D, but also others such as vitamin B12, minerals, trace elements, and essential fatty acids), then the behavioral disorder will regress after the deficiency has been rectified. Therefore, hyperactive or poorly focused children do not always have actual ADHD, even if they have been misdiagnosed as such.

Prevention is better – fix vitamin D deficiency with the sun

So there are very good reasons why you should pay attention to your personal vitamin D supply. Therefore, take care of regular sunbathing in the warm season. Do not worry. The right vitamin D supply does not require that you lie in the sun for hours and thus have to accept the risk of skin cancer.

A few minutes are enough to stimulate the formation of vitamin D in the skin in summer with intense sunlight and in light-skinned people. Yes, it is even the case that much longer sunbathing would no longer increase vitamin D production and would therefore not make sense, since the organism automatically protects itself from a vitamin D overdose. If the sky is overcast, staying outdoors must be longer, but then the risk of skin cancer is low or non-existent.

Note that sunscreens can block the UV-B radiation needed for vitamin D production (especially high SPF sunscreens), so you should stay sunscreen-free for the first few minutes of your tanning session.
If regular stays outdoors are not possible for you, you should definitely consider an appropriate vitamin D supplementation with vitamin D3 capsules.

You should also take into account that the organism has to take the necessary vitamin D from its own stores in winter since solar radiation in winter is not sufficient for vitamin D formation in Central Europe. Taking vitamin D is therefore highly recommended, especially in the winter months, because the vitamin D requirement cannot be met through diet.

Eliminate vitamin D deficiency: Food provides little vitamin D

Anyone suffering from a vitamin deficiency can usually easily remedy this with a targeted diet. With vitamin D, however, the situation is different. The vitamin is only found in a few foods and these usually only provide small amounts of the vitamin.

Traces of vitamin D can be found in milk and meat products, but these are not sufficient to cover the vitamin D requirement unless one likes to eat 1.5 kg of chicken liver, 20 kg of yogurt, or 10 kg of cheese per day.

Only some types of fish, such as eel, sardines, sprat, herring, etc., provide relevant amounts of vitamin D, but most likely you do not want to eat every day – especially not if you consider the toxic load of many fish caught, the drug residues in the fish from aquaculture and overfishing of the seas.

Vitamin D source Mushrooms

Fruits, vegetables, grains, and legumes do not provide any vitamin D at all. Plant sources of vitamin D are only mushrooms (2 – 3 µg/100g) and avocados (3 µg/100g).

In mushrooms, the vitamin D content depends on whether the mushrooms have had exposure to daylight or not. If you want, you can enrich your purchased mushrooms with vitamin D at home. You can do this by laying the mushrooms in the sun for a while.

However, mushrooms eaten without this extra treatment or even avocados do not provide enough vitamin D to meet the need.

The vitamin D requirement

The vitamin D requirement for adults is officially given as 20 µg (= 800 IU). However, more advanced doctors recommend a multiple of this amount of vitamin D – not least because experience has long shown that a vitamin D deficiency with these small doses of vitamin D can rarely be corrected in a reasonable period of time, if at all.

No wonder, in the case of serious illnesses, much higher amounts than those officially specified have long been assumed. In the case of multiple sclerosis, it is nine times the amount of vitamin D (approx. 180 µg) and for cancer prophylaxis even twelve times the amount (approx. 240 µg).

Correcting vitamin D deficiency: the procedure

If you now want to clarify whether some of the symptoms or diseases you suffer from could possibly also have something to do with a vitamin D deficiency, we recommend

  • Have your vitamin D levels checked (by a doctor or with a home test) and
  • depending on the result of the blood test, take a vitamin D preparation in the individually required dose.

Fix the symptoms

Of course, you will often notice enormous improvements in your well-being just by taking enough vitamin D, especially if you previously had a pronounced vitamin D deficiency. Many symptoms can subside or even disappear completely.

However, don’t forget all the other factors that are also part of good health care. Because vitamin D is of course important, but a good supply of vitamin D is not the only aspect of being healthy.

Other holistic measures that will help you stay or become healthy include the following:

  • Healthy eating
  • Drink enough good water
  • Building a healthy intestinal flora
  • Individually required dietary supplements
  • Relaxation
  • movement
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Written by Bella Adams

I'm a professionally-trained, executive chef with over ten years in Restaurant Culinary and hospitality management. Experienced in specialized diets, including Vegetarian, Vegan, Raw foods, whole food, plant-based, allergy-friendly, farm-to-table, and more. Outside of the kitchen, I write about lifestyle factors that impact well-being.

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