What Is Vitamin D Deficiency?

9 min

vitamin d deficiency

Vitamin D is also known as the “Sunshine vitamin” is one of the most important among the 13 vitamins needed for the human body. This is a very important vitamin for body and bone health in general. Let us take a deeper look at this vitamin D deficiency.

Sources and the body’s way of synthesizing Vitamin-D:

Sunlight is the major source of Vitamin D as its name suggests. So, apart from sunlight certain types of fish like sardines, salmons, liver, fortified food like cheese, cereals containing vitamin D, egg yolks, red meat, etc. are all good sources of vitamin D.

Eggs are good source of vitamin D

Apart from these commercial forms of Vitamin D in the form of daily supplements like chewable tablets, pills are also available.

As we know Vitamin D is synthesized in the body after exposure to sunlight occurs. A compound known as 7-dehyrocholesterol is available in the Malpighian layer of the epidermis. The ultraviolet rays from the sun break certain bonds to give rise to a pro-vitamin called secosterol. This is isomerized in the body to form Vitamin D3 also called cholecalciferol.

Vitamin D acts like a prohormone. The cholecalciferol is first transported to the liver to form a compound known as 25- hydroxycholecalciferol, which is a major storage form for this vitamin. It is then further hydroxylated to form calcitriol, which is the active form of the vitamin that also acts as a hormone.

Daily recommended intake of Vitamin D:

  • Children – 10 microgram (400 IU)
  • Adults – 5 to 10 micrograms (200 IU)
  • Pregnancy, lactation – 10 microgram
  • Above the age of 60 – 600 IU

Deficiency of Vitamin D:

When are we said to have a Vitamin D deficiency?

A level below 12 nanogram/milliliter of Vitamin D in the body.

This can be result from a lack of sunlight exposure, from which the majority of vitamin D produced.

In patients with gastro intestinal disease dietary deficiencies or mal absorption can occur.

Having seen, about vitamin D and how it is synthesized and used, its deficiency causes an array of manifestation mainly affecting the bone, muscles and teeth. However the way it manifests in adults and children differ markedly.

In general Vitamin D deficiency manifests as,

  • Weakness or pain in the muscle (myalgia)
  • Fatigue
  • Bone pain
  • Cramps
  • Mood changes
  • Depression
  • Rickets in children
  • Osteomalacia in adults

Apart from these a Vitamin D deficiency causes a marked reduction in the bone density leading to fractures and osteoporosis.

new born baby
Vitamin D deficiency in Children

Vitamin D deficiency in children can cause delayed development, muscle hypotonia (low muscle tone), craniotabes, bossing of the forehead region, swelling of the ribs costochondral junction, a condition generally called as ‘rickety rosery’. In addition it causes rickets in children since vitamin D is important for the absorption of calcium and phosphorous in the child’s body. This process is greatly hindered by lack of Vitamin D that hampers the growth of the child.

On the other hand, osteomalacia in adults present as osteoporosis, fracture, muscle and bone tenderness on pressure, malaise, fragility fractures, a waddling gait and a struggle to climb stairs and to get out of the chair are common.

Let us look at some of the other symptoms in detail and understand why they occur in that way,

Reasons for Vitamin D deficiency being on the rise

  • It is important to understand that Vitamin D’s predominant source is the Sun.

So the risk of suffering from Vitamin D deficiency increases proportionally when we reside in a country away from the equator.

  • A sedentary lifestyle is one of the most important reasons for the deficiency since there is inadequate exposure to sunlight and UV rays in these people.

Vitamin D deficiency and ethnicity:

  • Vitamin D deficiency is a very common disorder with roughly 1 million people around the world suffering from it.
  • This also varies with their ethnicity,

About 46.1% of the Americans, 69.2% of Hispanics, 82.1% of Afro-Americans are affected.

Vitamin D deficiency and skin complexion:

Our complexion also has a lot to do with this deficiency,

Studies have shown that young people with fair complexion tend to absorb more sunlight than dark skinned people. This is due to the fact that dark-skinned people have an abundant melanin pigmentation that hinders absorption.

Vitamin D deficiency and old age:

  • People in their senior years are more prone to this deficiency due to the reduced efficacy of the kidneys, which are unable to convert Vitamin D to its active form. This is further worsened in older adults with a dark complexion.
  • Other contributing factors are low dietary intake, kidney liver, and skin disorders, increased use of sun-blocking agents, a very indoor lifestyle, etc.

Vitamin D deficiency and obesity:

  • Studies have shown weight gain is associated with a deficiency of Vitamin D.
  • Though Vitamin D does not directly influence the body’s weight, the adipocytes or fat cells do not contain any particular Vitamin D receptors. Vitamin D certainly does have an influence over these cells by controlling the extent to which they can shrink or expand in certain regions.
  • So people with obesity or weight loss issues are advised to take a test to find out their Vitamin D levels.

Vitamin D deficiency and depression:

  • Vitamin D and depression are linked to each other, which has been proved by certain recent studies.

Studies in people with depression have shown low levels of Vitamin D in their bodies. This was also associated with impaired cognitive behavior. Hence a normal level of Vitamin D is essential for a healthy brain and mental health.

Vitamin D deficiency and constipation:

Vitamin D deficiency is associated with constipation. As we saw above stress and depression in Vitamin D deficient patients are commonly associated with chronic functional constipation associated with increased intestinal motility disorders. So it is very important to keep a constant check on the Vitamin D levels of these patients.

Vitamin D and loss of hair:

wet hair
Hair Loss

 Studies have shown an association between alopecia and Vitamin D,

  • Vitamin D deficiency is said to be one of the most common causes of thinning hair in both male and female population.
  • The upside is the hair loss caused due to this condition can be reversed. New hair growth and a reduction in hair fall happen once proper supplements are taken.

Vitamin D and dizziness:

  • A condition called Benign Paroxysmal positional vertigo (BPPV) is very common in people with Vitamin D deficiency. The person suffering from this condition has a feeling of the head or the inside of the head spinning. This was frequently associated with a deficiency of Vitamin D.
  • People also experienced frequent headaches associated with low blood levels of Vitamin D. This was especially common in women and was observed more during the daytime with associated fatigue. A low level of Vitamin D almost around 5.9ng/ml was reported in certain studies.

Vitamin D and joint pain and inflammation:

  • Recent studies have also shown that joint pain and swelling have been linked to low levels of vitamin D in the blood.

Vitamin D and hearing loss:

  • Low levels of Vitamin D have been associated with tinnitus or a prolonged ringing sensation in the ears. Deficiency of vitamin D and hearing loss are associated with each other because vitamin D affects the bone health of the body which includes the stapes which is the smallest bone of the body and is associated with the auditory functions.

Vitamin D deficiency and acne:

  • Though vitamin D is directly not associated with acne formation it contributes to it. An acne is caused by a variety of factors like excess oil from the underlying glands, hormone levels bacteria dirt etc. vitamin D can be a part of these symptoms making them even worse.

Vitamin D and iron deficiency:

It also hinders the iron absorption in the body hence predisposing the body to Iron deficiency anemia.

Vitamin D and medication:

Certain medications are known to cause vitamin D deficiency. There have been lots of studies that prove this. This might happen by way of the medication crossing the pathway involved in the synthesis of vitamin D, inhibition of the synthesis pathway, etc.

fish liver oil
Medications and Vitamin D

Following are some of the medications that cause vitamin D deficiency,

  • Certain laxatives (drugs that are administered to treat conditions like constipation)
  • Cholesterol-lowering drugs or statins like cholestyramine and colestipol
  • Anti-epileptics like phenobarbital and phenytoin
  • Rifampin is an anti-tubercular drug
  • Steroids like Prednisolone
  • Weight reduction drugs like orlistat.

Having seen the downside of the deficiencies caused by this vitamin, there are a lot of benefits too like vitamin D is said to help in weight loss by enhancing the diet we maintain in order to reduce weight. It promotes and maintains the immune system of the body. Protects and enhances the bones, teeth, muscles, and prevents problems like osteoporosis and pathological fractures.

Tests carried out to detect vitamin D deficiency:

Tests can range from simple blood tests to a bone biopsy.

  • A biochemical screen test to measure the serum 25(OH)D and the PTH (Parathyroid hormone) levels. Usually, elevated PTH levels are detected. Serum alkaline phosphatase levels increased and 25(OH)D levels are low or undetectable.
  • Serum calcium and phosphate levels may below.
  • Radiographic diagnosis is useful only when the condition had advanced.
  • A radiograph of the long bones, pelvis, and ribs are usually taken.
  • Radionuclide bone scans are helpful
  • Confirmation is done through a bone biopsy.


Having known a lot about this deficiency it is important to know the management of Vitamin D deficiency.

Osteomalacia and rickets, which are the two major forms of Vitamin D deficiency, can be managed by prompt treatment with Vitamin D supplements of 250-1000 microgram per day. This has shown rapid clinical improvement, with an elevation in the serum 25(OH)D and a reduction in parathyroid hormone. After 3 months after normal levels are observed in the serum ALP levels maintenance dose can be given.

In people with vitamin D deficiency oral ergocalciferol, which is a form of Vitamin D2, is given for 8 weeks at a dosage of 50000 IU. Once the condition normalizes vitamin D3 in the form of dietary supplements or pills with a dosage of 800-1000 IU can be taken.


Vitamin D2 and D3 are forms of vitamin D, which are derived from the fat of lamb’s wool. These are the natural forms of vitamin D that the body can easily take and further synthesize. Studies have shown both these forms are equally effective in curing Vitamin D deficiency.


This is yet another condition caused by excess intake of any vitamin in the form of supplements or dietary intake. Hence vitamins are not a joke, it could be a ‘double-edged sword’.The condition caused by taking excess vitamin D is said to be, “Hypervitaminosis D” which is usually rare but a serious complication.

Taking excess amount of supplemental vitamin D usually causes this condition (more than 60000 IU of vitamin D for several months in a row).

Manifestations include,

  • Hypercalcemia or excess amount of circulating calcium in the blood, which may cause nausea and vomiting, frequent urination and generalized fatigue.

 Taking the right amount of vitamins is equally essential. It is always advisable to get the doses modified by your doctor before taking any form of self-medication.


The ultimate aim of all the above said ways of management are bringing vitamin D into normal levels and maintaining them in order to avoid a lot of further complications.

Vitamin D deficiency or any other deficiency might seem like a very normal condition but it’s just the tip of a huge iceberg. One condition leads to another ultimately destroying the whole body. So it is always good to keep a check on the vitamin levels and always maintaining a healthy diet and taking those vitamin supplements without fail. Finally, it is always concluded with the golden saying, “Prevention is better than cure”.

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Dr Kavitha M

I am an undergraduate degree holder in dentistry. I have a great interest in music and reading. I am a linguaphile. My areas of interest lie in psychology, medical imaging, diagnostics, and oncology. I am a person who focuses more on the emerging areas of forensics.


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