Vitamin D – The sunshine vitamin

Available in abundance in our country, the sun is the primary source of Vitamin D for the human body. Find out why it’s so important to make sure you get enough time in the sun.Vitamin D is also known as the sunshine vitamin

Vitamin D – available in a sky near you!

Vitamin D, also called the sunshine vitamin, is a fat-soluble vitamin. It is needed in the body in large quantities, as it is responsible for the health of our bones and teeth, helps in fighting off infections and even improves mental health. Not only is it a vitamin, it is also a hormone and helps regulate insulin and calcium levels in the blood.

How the body utilises Vitamin D

The human body makes vitamin D when exposed to sunlight, or more specifically UVB rays. Plants have vitamin D in the form of ergosterol while cholesterol is the corresponding basic building block of vitamin D in humans. When a leaf of a plant is exposed to sunlight, it converts ergosterol into ergocalciferol or vitamin D2. In the same way, when human skin is exposed to sunlight, the body converts cholesterol into cholecalciferol, a form of vitamin D3. In humans, unlike in plants, this conversion is not the final step before vitamin D can be utilised by us. Cholecalciferol is converted into hydroxyl vitamin D in the liver, kidney, skin, brain and prostate. Next this is converted to dihydroxy vitamin D in the lungs, colon, spleen, liver, kidney, stomach and lymph nodes. This is the most active form of vitamin D required by humans and it lasts for a short time before it is eliminated so we constantly need vitamin D, much more than we thought was earlier required.

Sources of Vitamin D

Vegetarian sources:

Mushrooms that have been irradiated and yeast are vegetarian sources of this valuable vitamin.

Animal sources:

  • Fish like salmon, mackerel, catfish, sardines and tuna.
  • Eggs
  • Fortified milk, cheese, butter
  • Oysters
  • Fortified breakfast cereals, soy milk and margarine

Benefits of Vitamin D

Vitamin D has loads of benefits for the human body and getting enough of it should be a priority for everyone. Here’s a look at some of these important benefits:

  1. Helps in maintaining bone and teeth health by regulating bone calcium and blood calcium levels. It helps to prevent rickets and bone diseases like osteoporosis.
  2. Important in boosting immune function.
  3. Low levels of Vitamin D play a role in autoimmune diseases like rheumatoid arthritis, scleroderma.
  4. Helps in management of diabetes mellitus, prevents insulin resistance, high blood pressure, stroke and heart disease.
  5. Helps prevent muscle weakness.
  6. Helps regulate blood sugar balance.
  7. Lowers risk of bacterial infections and certain inflammations.
  8. Prevents cognitive decline, helps mental function in elderly.
  9. Helps prevent cancers of the bladder, breast, colon, prostate, ovaries and rectum.
  10. Prevents chronic fatigue.

Vitamin D deficiency

Not getting enough vitamin D in your system can have serious consequences:

  1. Vitamin D deficiency causes rickets in children and osteomalacia in adults. Rickets is more common in developing countries as children do not get enough vitamin D from their diet. It consists of deformities to the long bones, growth failure, convulsions and poor muscle tone. Osteomalacia is seen more commonly in women, especially after childbirth and breastfeeding.
  2. Lack of vitamin D can cause pain in the bones, soft bones, bone fractures
  3. It can also cause stunted growth in children.
  4. Asthma in children could be due to lack of vitamin D.
  5. Impaired cognitive function in the elderly.
  6. Lowered immunity
  7. Its deficiency may also lead to depression, especially in elderly.

Vitamin D toxicity

If overprescribed, vitamin D can cause toxicity. Symptoms include nausea, vomiting, lack of appetite, failure to thrive and kidney malfunction. Mental confusion has also been reported. However vitamin D deficiency is far more common than toxicity as the latter is unlikely from food sources alone.

Vitamin D in India

In tropical countries like India, chances of the skin making vitamin D are higher as compared to countries at higher latitudes where the sun may not be as strong due to shorter daylight hours. To maximise the amount of vitamin D made by the body, avoid using sunscreen and do not wear clothes that cover every inch of skin. Remember, only skin directly exposed to sunlight is useful in making vitamin D.

Recommended Daily Allowance of Vitamin D:

Adults: 2.5 micrograms or 100 IU.

Infants and children: 5 micrograms or 200 IU.

Pregnant and lactating women: 10 micrograms or 400 IU.

Written by Dr Nisreen Nakhoda, General Physician

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