Vitamin D, scientifically known as calciferol, is a fat-soluble vitamin essential for survival. In addition, vitamin D helps absorb calcium, promotes bone growth, keeps our teeth strong, and maintains phosphorous levels in the blood.
Vitamin D modulates the immune system and aids in antibody synthesis. It is essential to our neuromuscular system and prevents the body from getting neurocognitive disorders. In addition, our skin makes significant portions of Vitamin D required by our body from sunlight. Therefore, sun rays are essential to keep our Vitamin D levels intact.
So, what happens if the Vitamin D level needed by our body for proper functioning goes down? This article briefly describes Vitamin D deficiency, its causes, risk factors, symptoms, diagnosis, and management.

What is Vitamin D deficiency?
Vitamin D deficiency/ Hypovitaminosis D is a condition when the human body does not have enough Vitamin D. We can say that the amount of Vitamin D in the body is below normal. Vitamin D levels in the body are determined by the concentration of serum 25-hydroxyvitamin D. The required or the exact level of Vitamin D in the human body is still controversial. Of many known and unknown reasons, one reason supporting the different optimal levels of Vitamin D in populations across the globe is the substantial differences in mineral metabolism among other races. However, the International Society for Clinical Densitometry and the International Osteoporosis Foundation recommend serum 25-hydroxyvitamin D levels of 30 ng/mL to reduce the risk of fall and fracture in the aged population.

What causes Vitamin D deficiency in humans?
Vitamin D deficiency in humans can be due to many reasons, including:

  1. Insufficient intake of diet rich in Vitamin D/ Decrease in Absorption of Vitamin D
    People who suffer from malabsorption syndromes such as short bowel syndrome, celiac disease, inflammatory bowel disease, and chronic pancreatitis may have decreased absorption of Vitamin D in the body leading to its deficiency. In addition, some Elderly populations and children do not take Vitamin D-rich foods in their diet due to negligence or financial difficulties. This may also lead to Vitamin D deficiency.
  2. Total cut-off from sunlight or not getting exposed to the sun for many days
    Sun is the source of life for every living being. The human body needs sunlight to produce Vitamin D naturally. We should know and remember that 50-90% of Vitamin D required by our body is made by our skin when exposed to sun rays. The remaining portion comes from the diet. Therefore, people should habit of getting their head, face, hands, back, and legs exposed to sun rays during the morning for 30 minutes every day.
    People who stay indoors for a longer duration, or are under prolonged hospitalization, or reside in cold geographic regions far away from the equator have high chances of getting Vitamin D deficiency. In addition, people who regularly use sunscreens throughout the year also have high options of decreasing Vitamin D synthesis by the skin when exposed to sun rays.
  3. Decrease in the function of Kidneys
    People suffering from chronic kidney diseases or undergoing dialysis have high chances of getting Vitamin D deficiency. A decrease in the availability of 25-hydroxyvitamin D by renal proximal tubular cells, high fibroblast growth factor (FGF)-23, and decreased functional renal tissue lead to Vitamin D deficiency.
  4. Overweight or obesity
    Obesity can lead to Diabetes, cardiovascular problems, Vitamin D deficiency, and many other diseases. Scientists have found that low Vitamin D levels lead to high BMI in patients. Eating unhealthy and fried foods, drinking sugary drinks, lack of exercise, a sedentary lifestyle, and specific health and genetic conditions lead to obesity. Obesity pushes the human body towards a dangerous cycle of Vitamin D deficiency, cardiovascular risks like heart attack, and endocrinological disorders like Diabetes.

Other Important Risk Factors for Vitamin D deficiency includes:

  • Elderly population
  • People living far from the equator or having longer winter months
  • People who have undergone gastric bypass surgery
  • People suffering from diseases like celiac sprue, end-stage liver disease, and cystic fibrosis
  • Decreased Endogenous synthesis and End Organ resistance
  • Patients taking medications that cause Vitamin D degradation (Example of medications include antiretroviral drugs used for HIV, antiepileptic drugs, statins that act as cholesterol-lowering drugs, and glucocorticoids)
  • Skin Color and Breastfeeding Women

What are the symptoms of Vitamin D deficiency?
The symptoms of Vitamin D deficiency include:

  • Pain in the bones and back
  • Loss in bone density
  • Myalgia (pain in the muscles) along with muscle cramps
  • Depression
  • Fatigue
  • Alopecia
  • Weight gain
  • Decrease in immunity leading to easily affected by infections or getting sick

How is Vitamin D deficiency diagnosed?
People with the above symptoms should visit a physician to diagnose their Vitamin D deficiency. The diagnosis of Vitamin D deficiency involves a blood test that measures the level of 25-hydroxyvitamin D (25(OH)D).
After the blood test, the physician analyses the results and categorizes Vitamin D deficiency in three stages:

Stage 1: Mild Deficiency
The stage where the level of 25-hydroxyvitamin D is less than 20 ng/mL
Stage 2: Moderate Deficiency
The stage where the level of 25-hydroxyvitamin D is less than 10 ng/mL
Stage 3: Severe Deficiency
The stage where the level of 25-hydroxyvitamin D is less than 5 ng/mL

What are the health complications of Vitamin D deficiency?
Vitamin D is essential for the human body. Deficiency of Vitamin D along with late diagnosis and lack of proper management can lead to multiple health complications like

  • Rickets
  • Respiratory Illness
  • Osteoporosis and Osteomalacia
  • Depression
  • Schizophrenia
  • Hyperparathyroidism
  • Dementia
  • Diabetes
  • Prostate Cancer
  • Severe Erectile Dysfunction
  • Heart Disease
  • Breast Cancer
  • Autoimmune diseases (Multiple Sclerosis & Type I diabetes)
  • Infections and Immune system Disorders

How to manage and treat Vitamin D deficiency?
Vitamin D deficiency can be treated by following a diet rich in Vitamin D and getting proper sunlight exposure for 30 minutes daily during the morning. Exposure to sunlight during the early morning, along with exercise, is a must for patients suffering from Vitamin D deficiency or those who have obesity and Diabetes. One can also take Vitamin D supplements as prescribed by the physician. Always take the advice from a dietician about the number of foods and the right food for your body towards managing Vitamin D Deficiency.

Food items that are rich in Vitamin D and helps in recovery from Vitamin D deficiency include:

  • fortified milk products (unadulterated milk, cereal, and yogurt)
  • shrimp
  • fortified orange juice
  • wild mushrooms
  • fortified cereals & oatmeal
  • cod-liver oils
  • fatty fish (rohu, trout, tuna, salmon, and herring)
  • egg yolks
  • Goat Liver


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