Vitamin D is a fat-soluble vitamin that is made when the skin is exposed to sunlight. It is made from cholesterol in the skin. Known as the sunshine vitamin, vitamin D is produced by the body in response to skin being exposed to sunlight. Produced by the skin when it soaks up the sun’s ultraviolet (UV) rays.

It’s main function is regulation of calcium and phosphorus levels in the blood, vital for maintaining healthy bones. Vitamin D is essential for strong bones, because it helps the body use calcium from the diet. Research suggests that vitamin D could play a role in the prevention and treatment of a number of different conditions, including type1 and type 2 diabetes, hypertension, glucose intolerance, and multiple sclerosis.It also helps ward off respiratory infections such as flu, cough and cold.

Vitamin D intake is not the best measure of the vitamin’s status in the body, as many factors can affect its uptake. For example, the health of the stomach can interfere with how much vitamin D a person absorbs from the food they eat.

Health Risks of Vitamin D Deficiency

  • Increased risk of death from cardiovascular disease
  • Cognitive impairment in older adults
  • Severe asthma in children
  • Cancer
  • Rickets

Causes of Vitamin D Deficiency

  • Living at high latitude: This is due to there being less access to the sun’s ultraviolet-B (UVB) rays.
  • Being indoors too much: Spending little or no time outside means missing out on the sun’s rays.
  • Living in a highly polluted area: Smog and pollution in cities can also block the sun’s rays.Pollution can absorb some of the sun’s rays.
  • Using large quantities of sunscreen: Using enough sunscreen to block UV rays might inhibit vitamin D absorption. But few people use enough sunscreen to block UV rays fully.
  • Over clothed
  • Having darker skin: People with darker skin need more sunlight exposure to absorb enough vitamin D. The pigment melanin reduces the skin’s ability to make vitamin D in response to sunlight exposure.
  • Ambient temperature: Warm skin is better at absorbing the sun’s rays to produce vitamin D than cool or cold skin.
  • Diet: Eating foods rich in vitamin D, or foods that have been fortified with the vitamin, reduces the risk of vitamin D deficiency.
  • Being overweight: This may be because excess body fat affects vitamin D absorption.People with a body mass index of 30 or greater often have low blood levels of vitamin D.
  • Age: People’s ability to absorb vitamin D may decline with increasing age. As people age, their kidneys are less able to convert vitamin D to its active form
  • Gut health: Disorders that affect the gut, such as Crohn’s disease, cystic fibrosis, and celiac disease can undermine the intestines’ ability to absorb vitamin D from the food you eat.Your digestive tract cannot adequately absorb vitamin D.
  • Kidney and liver health: People with liver or kidney disease tend to have lower vitamin D levels.
  • Pregnancy or breast-feeding: The nutritional demands of an infant or foetus may lower vitamin D levels, particularly in women already at risk of vitamin D deficiency.
  • Being a breast-feeding infant: Human milk is low in vitamin D. Infants who are nursing may need a vitamin D supplement, particularly if they do not go outdoors every day.
  • Poor nutrition

In a random study of people from Indian metro cities we found that 50%- 70% had vitamin D deficiency.

The symptoms of vitamin D deficiency can be vague, may change over time, and are similar to symptoms of a wide range of ailments. Hence, it is dangerous to self-diagnose a vitamin D deficiency.

Some symptoms of a deficit in vitamin D include:

  • thinning or brittle bones, osteoporosis, or frequent bone fractures
  • bone pain &muscle weakness, particularly if there is an unexplained change in muscle strength
  • changes in mood, with people who have low vitamin D experiencing anxiety or depression
  • chronic pain, as vitamin D plays a key role in supporting bone, muscle, and cell health
  • high or rising blood pressure
  • exhaustion, even with enough sleep
  • decreased endurance
  • unexplained infertility
  • suppress immunity
  • come in the way of weight loss
  • hair loss
  • disturbed sleep.
  • In children, low vitamin D levels can lead to the softening of bones, which can lead to bow-legs and knock knees.

Tests for Vitamin D Deficiency :

The most accurate way to measure how much vitamin D is in your body is the 25-hydroxy vitamin D blood test. A level of 20 nanograms/milliliter to 50 ng/mL is considered adequate for healthy people. A level less than 12 ng/mL indicates vitamin D deficiency.

Treatment for Vitamin D Deficiency.

The most accurate way to measure how much vitamin D is in your body is the 25-hydroxy vitamin D blood test. A level of 20 nanograms/millilitreto 50 ng/mL is considered adequate for healthy people. A level less than 12 ng/mL indicates vitamin D deficiency.

Vitamin D Deficiency & Supplementation:
Management of vitamin D deficiency involves getting more vitamin D — through supplements and taking the Sun. Although there is no consensus on vitamin D levels required for optimal health — and it likely differs depending on age and health conditions — a concentration of less than 20 nanograms per milliliter is generally considered inadequate, requiring treatment.

When the sun slants, the light travels through more ozone before reaching Earth’s surface, which in turn reduces UVB exposure at the surface (the three types of ultraviolet radiation-UVA, UVB and UVC-are classified according to their wavelength). UVB rays are the primary source of vitamin D.

The level of UV radiation varies with the time of day and year. It’s weakest when the sun slants, which is during the early and later parts of the day, and during most of the day in winters. So the closer to midday you expose your skin, the better it will be for vitamin D production. If you look at your shadow and it’s smaller than you, then it’s within the time range to produce D.

The best way to get Vitamin D is from the sun. Spend 15 to 20 minutes a day in direct sunlight ideally between 11 am to 4 pm without any sunblock or sun glasses, 3 to 5 times a week. Do not wear sunscreen during this time as this will prevent your skin from absorbing the vitamin.

A pan-India study has revealed that the best time to get exposed to the sun is between 11am and 1pm since the wavelength of ultraviolet B (UVB) rays is 290-320nm during this period which is essential for skin to make vitamin D.Some scientists recommend exposing around a third of the area of your skin to the sun. The facial skin and head can be kept covered. Back of the neck, arms, legs are good to expose to the sun and even the torso

About 40% women and 30% men in India develop vitamin D-induced osteoporosis, a condition that causes bones to become weak and brittle.

It’s important to note that the sun’s UVB rays cannot penetrate through glass windows.

Guidelines from the Institute of Medicine has increased the recommended dietary allowance (RDA) of vitamin D.

1 to 70 years of age: 600 to 1000 IU per day

More than 70 years: 800 to 2000 IU per day

5000 IU per day for 9 weeks can be advised for deficiency.


Those who have Vitamin D deficiency may need a higher dosage of Vitamin D3 than the RDA.

Plant based Vitamin D3 supplements are available these days. The dosage and duration of supplements can be planned with the advice from a health care professional.

Taking vitamin D supplements in larger doses for a longer period can cause hypervitaminosis D. Do not over- supplement or supplement without testing. However, you can never get too much vitamin D from the sun.