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Vitamin D Deficiency - Causes, Symptoms, Diagnosis, and Treatment

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Vitamin D Deficiency - Causes, Symptoms, Diagnosis, and Treatment

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Vitamin D is an essential fat-soluble vitamin. It is a hormone or a pro-hormone. Read the article below to learn about its deficiency.

Medically reviewed by

Swapan Banerjee

Published At January 16, 2019
Reviewed AtMarch 6, 2023

What Is Vitamin D?

Vitamin D is a fat-soluble vitamin that is required for the regulation of minerals like calcium and phosphorus in the body. It is also essential to maintain proper bone structure, as it helps in the absorption of calcium from the food in the intestines. If not, the calcium in our diet will be excreted through the kidneys. In addition, recent research also shows its role in maintaining the nervous, muscle, and immune systems.

Vitamin D also regulates cell growth and helps in cell-to-cell communication. The hormonally active form of vitamin D (calcitriol) has been shown to slow the growth and development of new blood vessels in cancerous tissues. Thus it reduces the progression of cancer by increasing the rate of death of cancer cells and by preventing cell proliferation.

It influences more than 200 human genes. Recent research has also associated the deficiency of this vitamin with increasing the risk of hypertension (high blood pressure), multiple sclerosis (immune system diseases affecting the protective structure around the nerves), cardiovascular disease, autism, asthma, and many other diseases. Lately, there is mounting evidence suggesting that pregnant women are at a higher risk of pre-eclampsia (a complication of pregnancy characterized by high blood pressure, increased urine, etc.) and premature labor if their vitamin D level is not optimum.

What Are the Sources of Vitamin D?

Our body cannot create other nutrients and vitamins, but our body can synthesize vitamin D on exposure to the sun. For example, when the parts of your body are exposed to the sun, the skin makes vitamin D from cholesterol. Also, there are a few other natural sources of vitamin D available.

The other sources are:

  • Vegetarian Sources - Cheese, mushroom, orange, tofu, soy chunks, and fortified cereals.

  • Non-vegetarian Sources - Fatty fish like salmon, tuna, mackerel, eggs, meat, beef liver, etc.

What is Vitamin D Deficiency?

When the level of vitamin D becomes too low in the body and affects the bone, it is known as Vitamin D deficiency. Vitamin D actually functions as a hormone, so it is called pro-hormone, and all the cells in the body have a receptor for it. To understand the effects of vitamin D deficiency, we must first know the role played by this vitamin in maintaining our health.

What Are the Causes of Vitamin D Deficiency?

If the serum vitamin D level is less than 20 ng/mL, then a person is at risk of developing vitamin D deficiency, and serum levels below 12 ng/mL indicate deficiency. Scarcity occurs when an individual does not consume enough vitamin D or if the body is not able to absorb and metabolize the consumed vitamin.

Some of the risk factors and causes are as follows:

  • Spending a lot of time indoors may cause vitamin D deficiency due to reduced exposure to the sun's rays.

  • People living in higher altitudes have less sun exposure.

  • Pollutants absorb some of the sun’s rays, so people living in polluted areas get less sun exposure.

  • Indiscriminate use of sunscreen lotions.

  • The skin of darker people needs more sunlight exposure to synthesize vitamin D.

  • Consuming food that lacks vitamins and other nutrients.

  • In obese people, excess body fat affects vitamin D absorption.

  • The ability to absorb vitamin D decreases as the person ages.

  • People who are suffering from malabsorption syndrome.

  • Women who are pregnant or breastfeeding are at risk, as they have to fulfill the nutritional demands of the growing baby.

  • Breastfeeding infants are also at risk as human milk is low in vitamin D.

What Are the Signs and Symptoms of Vitamin D Deficiency?

The symptoms you will commonly experience are:

  • Brittle bones.

  • Tiredness or fatigue.

  • Often catching a cold and flu.

  • Painful joints and back.

  • Feeling depressed.

  • Hair loss.

  • Muscular pain.

Long-Standing Deficiency Might Lead To:

  • Osteoporosis (weakening of bones).

  • Diabetes.

  • High blood pressure.

  • Obesity.

  • Fibromyalgia (a disorder characterized by extensive tenderness and pain in the muscles).

  • Depression.

  • Chronic fatigue syndrome.

  • Alzheimer’s disease.

  • Breast, colon, and prostate cancers.

  • Unexplained infertility.

What Are the Disorders Associated With Vitamin D Deficiency?

Vitamin D is said to be necessary for calcium absorption; hence its deficiency causes impaired calcium absorption, which results in many bone disorders.


The softening and weakening of bones in children is called rickets. Calcium and phosphate are required for the healthy growth and mineralization of bones, and vitamin D is needed to regulate this calcium and phosphate balance. A lack of mineralization of the growth plate in children causes rickets. This mineralization defect can be calcipenic (hypocalcemic) or phosphopenic (hypophosphatemic) rickets. As vitamin D helps in the absorption of calcium from the gut, vitamin D deficiency is the most prevalent cause of rickets than isolated calcium or phosphate deficiency.

It causes delayed growth, pain in the spine, pelvis, legs, and back, muscle weakness, bowed legs (knock knee), breastbone projection, and thickening of wrists and ankle bones. Children with long-standing vitamin D deficiency can have an abnormally curved spine, skeletal deformities, dental defects, impaired growth, and seizures.


The softening of bones in adults or children due to problems with the bone formation or the bone-building process causes osteomalacia. The most common cause of osteomalacia is vitamin D deficiency.

The soft weight-bearing bones can get bowed during growth. As the condition progresses, people experience bone pain and muscle weakness. Pain is commonly felt in the lower back, pelvis, hips, legs, and ribs.


Osteoporosis is a bone disorder that reduces bone density making it more susceptible to fracture. Sometimes the bones become so brittle that mild forces like bending or coughing can cause fractures.

Patients with osteoporosis have back pain due to a fracture or collapsed vertebra, loss of height over time, stooped posture, and frequent bone fractures.

How to Diagnosis the Deficiency of Vitamin D?

A 25-hydroxy vitamin D blood test measures the levels of vitamin D in your body. The normal range is 20 to 50 ng/mL. Anything less than 12 ng/mL indicates vitamin D deficiency.

What Are the Treatment Modalities for Vitamin D Deficiency?

There are three ways that can increase vitamin D levels:

  • Administration of Vitamin D Supplements: The doctor might prescribe a supplement or multivitamin, depending on the severity of your deficiency.

  • Taking the Daily Dietary Allowance of Vitamin D: Consuming foods that are rich in vitamin D, like fish, meat, eggs, and cheese, can help prevent vitamin D deficiency. One can also take foods that are fortified with vitamin D.

  • Increased Exposure to Sun: Spending a little more time outdoors will increase your sun exposure. Try to spend a minimum of 15 to 20 minutes three to four times a week.


Vitamin D is an important vitamin for the body and specifically for the bones. An individual should make sure that they get enough vitamin D from their diet. If not, then intake supplements after consulting a health care provider. If a person falls under the high-risk category, checking vitamin D levels regularly is better, as its deficiency causes many chronic bone disorders. It is always recommended that to lead a healthy life, do some physical activity daily and eat healthily.

Frequently Asked Questions


Which Fruit Is High in Vitamin D?

There are no fruits that have a high vitamin D content in them, and fortified orange juice is the only fruit product that is readily available and sold with vitamin D currently. Instead, you can try egg, cheese, and other dairy products.


Does Vitamin D Reduce Belly Fat?

Research has proven that vitamin D deficiency could cause weight gain issues, which results in excess belly fat. Many studies investigated the effects of vitamin D on a person's weight loss and gain. Those studies suggested that vitamin D could decrease fat cells' storage, and that can result in an effective reduction of fat accumulation in the body.


Can Vitamin D Deficiency Cause Stomach to Bloat?

Problems that affect a person's digestive tract can cause incomplete absorption of Vitamin D in the gastrointestinal tract. So if a person experiences symptoms such as chronic gas, abdominal bloating, and constipation or conditions like "irritable bowel" syndrome, that person should get his or her vitamin D levels checked.


Which Vegetable Is High in Vitamin D?

Practically, there are no vegetables that are rich in vitamin D. You can get vitamin D from other sources. They are:
- Cow's milk.
- Orange juice.
- Various breakfast cereals.
- Spinach.
- Egg yolk.


Does Vitamin D Help You Sleep?

Research states that vitamin D levels are capable of affecting sleep quality in people. Also, several studies state that low levels of vitamin D in a person's blood put them at a higher risk of experiencing sleep disturbances, poor sleep quality, and reduced sleep duration.


Why Does My Child Have Low Vitamin D?

Children who have medical conditions that affect the body's nature of absorbing and controlling vitamin D, like any liver disease, kidney disease, or problems with the absorption of food such as cystic fibrosis can have low levels of vitamin D. The celiac disease, inflammatory bowel disease, and certain anti-epileptic medicines can lower the level of vitamin D.


What Is Vitamin D Deficiency in Children Called?

The presence of deficient vitamin D levels can cause soft bones, which leads to a condition known as rickets in children. At the same time, low vitamin D levels are called osteomalacia in young adolescents and adults.


What Conditions Result in Vitamin D Deficiency in Children?

Most of the people who are affected by low vitamin D levels usually do not have any symptoms. However, some children who have low vitamin D levels complain of bone and muscle pain. A deficient vitamin D level can cause softness in bones and rickets in children.


What Are the Symptoms of Vitamin D Deficiency in Adults?

The signs and symptoms experienced by adults having low vitamin D levels include:
- Fatigue.
- Bone pain.
- Muscle weakness with associated muscle aches, or muscle cramps.
- Mood swings and depression.


How Can I Raise My Vitamin D Level Quickly?

You can increase your Vitamin D levels very quickly by the methods mentioned below.
- Spend adequate time in sunlight since it is the popularly known "the sunshine vitamin."
- Consume the right amount of fatty fish and seafood.
- Eat more mushrooms.
- Increase the consumption of egg yolks in your diet.
- Eat fortified food products.
- Take a vitamin D supplement as prescribed by a doctor.


What Is a Normal Vitamin D Level for a Woman?

A level of at least 20 to 50 ng/mL of vitamin D is considered adequate for healthy people. A level of vitamin D that is less than 12 ng/mL is significant for vitamin D deficiency.


Can You Check Vitamin D Levels at Home?

Yes, it is possible to measure your vitamin D levels and compare them with healthy ranges. This is known as the at-home test that can be used to ensure that you have sufficient vitamin D levels that are needed to maintain bone and cellular health.


How Do I Know If I Am Low on Vitamin D?

You might experience symptoms if you are affected by vitamin D deficiency, including muscle weakness, muscle pain, fatigue, and depression-related mood disorders.


Is Vitamin D Deficiency Serious?

Yes, vitamin D deficiency is serious as it can cause a loss of bone density, contributing to osteoporosis and frequent fractures. Vitamin D deficiency can also lead to other secondary conditions in severe cases. In children, it can cause a severe but rare medical condition known as rickets.


Can Vitamin D Deficiency Affect Mood?

Vitamin D deficiency is often related to an increased risk of getting affected with depression. Low levels of vitamin D might also lead to poorly regulated moods and behaviors and impair the brain's cognitive function.


How Long Does It Take to Recover From Vitamin D Deficiency?

The dosage for vitamin D will be given based on your age. The causes of reduced levels of vitamin D should be considered. After six to eight weeks of treatment procedure for vitamin D, the dosage of vitamin D will be reduced. After this stage of treatment, you can continue on the low dosage of vitamin D.


What Happens If Your Vitamin D Is Too Low?

Vitamin D is a component that is essential for the proper functioning of the bones. Bones are necessary for regular activities like walking, running, picking up an object. If the level of vitamin D is low, then there are chances for bone fractures and other bone problems like osteoporosis. In children, it can cause diseases like rickets. Rickets causes softening of the bones and leads to bending in severe patients.


How Can I Increase My Vitamin D Level?

Vitamin D can be increased in the following ways. They are:
-Sunlight is an important source of vitamin D. Spend more time outdoors so that you will receive more sunlight naturally.
- Consume mushrooms in higher quantities.
- Eat fatty fish and other seafood like prawns and oysters.
- Eat foods that are fortified.
- Take egg yolks every day.


Can Lack of Vitamin D Cause Weight Gain?

Researches show that vitamin D deficiency can have a significant influence on weight gain. Vitamin D should be at an adequate level to maintain a healthy weight. However, there might be other reasons for your weight gain. Identifying that would be the first step for formulating a treatment plan. If vitamin D deficiency is the only reason for your weight gain, you should immediately consult your doctor.
Swapan Banerjee
Swapan Banerjee



vitamin d deficiency
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