Skip to content

Vitamin D Deficiency: Causes – Risk Factors and Symptoms

Vitamin D deficiency

Vitamin D deficiency is quite a common health problem in today’s world. And, if left untreated, it can cause serious health conditions. In this article, we are going to examine everything about vitamin D deficiency, including the symptoms, signs, risk factors and causes.

However, before addressing this issue, it is plausible to briefly describe vitamin D and why it is crucial for the human body.

Please note that the information given below regarding vitamin D and vitamin D deficiency symptoms/signs compiled based on reliable scientific sources. Nevertheless, the information below not intended to be a substitute for your doctor’s advice, diagnosis or treatment.

Vitamin D

Vitamin D is a type of vitamin that is vital for the human body. Therefore, it is no coincidence that many diseases and ailments occur due to vitamin D deficiency.

In order for an individual having a healthy life, the person should pay attention to the daily vitamin D intake as well as other important factors necessary for a healthy life.

According to Mayo Clinic; recommended daily vitamin D intake should be 400 IU ( international Unit ) for 0-12 months, 600 IU for 12-70 years, 800 fand or people over 70 years of age.


Vitamin D Functions In the Body

As mentioned in the previous section, vitamin D is an indispensable vitamin for the human body. If we need to enumerate a few of these important functions;

♣ Vitamin D plays vital roles in the functioning of the nervous system as well as the muscle-skeletal system.

♠ Vitamin D is one of the main components of the immune system –which protects us against diseases viruses and other harmful microorganisms.

♣  Calcium is one of the building blocks of bones in the body because this mineral builds and protect bones throughout the body. But, the human body needs vitamin D to absorb calcium. Therefore, medical sources and doctors repeatedly emphasise the importance of vitamin D for bone health.

How to Get Vitamin D

The fact is; that the human body cannot produce vitamins by itself. Therefore, we need to take vitamins from outside sources mostly through foods.

We can obtain vitamin D – which is one of the most vital vitamin types for the human body – in 3 different ways.

1- Sun Exposure

We have just said that the human body cannot produce vitamins by itself and must be taken from outside through foods. But the exception here is vitamin D.

The human body can produce vitamin D on its own. Of course, this requires exposure to the sunlight. To put simply, the human body can convert sunlight into vitamin D.

According to Cleveland Clinic; 15-20 minutes 3 days each week is sufficient for your body to produce vitamin D.

2- Foods

Although the number of vitamin-D-containing foods is limited, it is essential to consume them as required, especially in the winter months. 

According to NHS; oily fish such as salmon or sardines, red meat, liver, egg yolks and fortified foods like breakfast cereals are the primary sources of vitamin D.

3- Nutritional Supplements 

The third and final way of taking vitamin D is through vitamin supplements.


Risk Factors for Vitamin D deficiency

Some factors make some people more susceptible to vitamin D deficiency. Therefore, it is important to know the risk factors of vitamin D deficiency. 

The following are risk factors for vitamin D deficiency.


1- Old Age

Vitamin D is one of the rare vitamins that the human body can produce by itself along with vitamin K. When the skin comes into contact with sunlight, the body converts it to vitamin D. However, as getting older, the body loses its ability to produce vitamin D, that makes elderly people vulnerable to vitamin D deficiency. 


2- Skin Colour

 It has been proven by scientific studies that people with darker skin have less capacity to produce vitamin D than people with fair skin. One of these scientific studies has proven that African-Americans carry more risk for vitamin D deficiency.

Scientists explain this phenomenon with the fact that people with darker skin have more melanin in their skin relative to people with fair skin. Because, melanin inhibits the production of vitamin D. The result is the more melanin there is in the body, the harder for the body to produce vitamin D. 


3- Obesity

Obesity is a health problem that is held responsible for many diseases on earth. Scientific studies demonstrate the link between obesity and vitamin D deficiency.


4- Kidney and liver disease

Kidney or liver disorders are indicated as other risk factors for vitamin D deficiency. Even if a person with kidney or liver disease does not have a problem in getting vitamin D into his/her body, the person’s body may have trouble producing enzymes that make vitamin D usable in the body due to either kidney or liver disease. As such, the body cannot produce a sufficient amount of vitamin D.


5- Location

One of the risk factors for vitamin D deficiency is the location of an individual in the world. Especially during the winter months, the amount of received sunlight decreases in places far away from the equator. The problem is related to the sun’s angle of incidence.

The conclusion is individuals who live away from the equator have a higher risk of developing a vitamin D deficiency, particularly in the winter months.


Vitamin D Deficiency Signs

It bears repeating that, vitamin D plays crucial role in human health. With this in mind, it is obvious that vitamin D deficiency can lead people to various health problems.

When a person experiences low-level vitamin D, the body gives certain alarms. However, these symptoms may be a symptom of another disease. Therefore, it is not always easy to differentiate the symptoms.

Below-given the main signs of vitamin D deficiency can help in diagnosing the problem. Please note that a definitive diagnosis is made through laboratory tests.


1- Fatigue and Tiredness

In the modern world, we feel tired for various reasons. These include stress, depression, poor diet, etc.

Therefore, it is not easy for a person who suffers from long-term fatigue to get suspicious of lacking vitamin D.

Long-lasting and excessive fatigue and weakness may indicate vitamin D deficiency in the body. A  scientific report proves the relationship between tiredness/fatigue and a low vitamin D level.


2- Getting Sick Easily

In the introduction of the article, we talked about how crucial role vitamin D has on the human body’s immune system. In this context, it should not be surprising to hear that the immune system weakens in the case of a deficiency of this vital vitamin.

Vitamin D supports our body’s defence system against viruses and bacteria. So if you get sick more often than the average person does, this may indicate a low vitamin D count in the body.


3- Bone and Back Pain

Vitamin D functions in the absorption of calcium, which is very important for our muscle and bone health. For this reason, vitamin D deficiency is associated with back and bone pain.

To validate this claim, it is sensible to refer to a scientific article showing that vitamin D causes pain in the back and various bones.


4- Depression 

According to experts; persistent depressive mode is another symptom of vitamin D deficiency. Especially, older people are more vulnerable to depression caused by vitamin D deficiency relative to young individuals.

Scientific research; shows that depression caused by vitamin D deficiency is more common at later ages.


5- Impaired Wound Healing

There are many medical studies indicating the relationship between vitamin D deficiency and delayed wound healing. People with low-level vitamin D may suffer from slow wound healing since vitamin D has a role in the process of providing new and healthy skin formation.

Therefore, it would not be inaccurate to say that the wounds that heal later than should be is an indication of vitamin D deficiency.


6- Hair loss 

Hair loss can befall an individual for many reasons or can occur due to a combination of many factors.
And stress is shown as the main cause of hair loss. Researchers reveal that hair loss occurs in the case of vitamin deficiencies including vitamin D.

However, in order to say that the main cause of hair loss is vitamin D deficiency, the amount of falling hair must be too much. Moreover, hair loss related to vitamin D deficiency affects women more than affects men.


Tarkan is an experienced health writer ( currently more than 600 articles ) and also the founder of this website namely His expertise in health stems from in-depth medical research and knowledge which he obtained over the course of many years.

Tarkan enjoys sharing factual knowledge on health, psychology and nutrition. He always aims to deliver evidence-based recommendations, provide links to related scientific studies.

[email protected]