Vitamin D and Immunity: The Sunshine Vitamin

By Dr. Suruchi Goyal Agarwal, Consultant – Paediatrics and Paediatric Endocrinology, Columbia Asia Hospital Whitefield

Most of us know that Vitamin D is essential to maintain the health of our bones. However, most of us aren’t aware that this amazing Vitamin has a crucial role to play in our immune system!

What is Vitamin D

Vitamin D belongs to class of fat-soluble vitamins and was first discovered along with many other vitamins in the 1920’s.  Unlike other Vitamins that have rich nutritional sources and can be used as such when we consume them, Vitamin D is found in limited food sources and even when ingested needs to be changed to an active form for the body to use it effectively. It is one of the only vitamins that our body produces. Vitamin D that we either ingest or produce using the UV rays from the sun passes through the liver and kidneys where it is activated. The cells of our immune system also have the capability to activate Vitamin D when needed.  Essentially in many ways Vitamin D acts like a hormone!

Immune boosting effects:

The immune system forms an essential defense mechanism of the human body against invading viruses, bacteria and other foreign organisms, hence providing protection.

The last decade has seen a lot of research that has brought to light the role of Vitamin D the optimal functioning of the immune system. Receptors known as Vitamin D receptors (VDR) have been found on various cells other than those in the bone and gut proving that this Vitamin does a lot more than improving bone health. These receptors have been found in the bone marrow, breast, colon and immune cells too.

Studies have made it clear that adequate levels of Vitamin D in the body confers better immunity against viruses such as the influenza virus and viruses and bacteria that cause upper respiratory infections leading to less sick days. These viruses and bacteria upon entry in our body are confronted by cells called ‘macrophages’ which in simple terms swallow the microbes and destroy them. This destruction of microbes is enhanced by the activity of vitamin D. It has also been shown that Vitamin has a protective effect in many conditions like pneumonia and ARDS.

In addition, it is becoming increasingly clear that adequate levels of Vitamin D are also essential for slowing the progression of autoimmune diseases (these happen when our immune system appears to attack our own cells) like Rheumatoid arthritis, inflammatory bowel disease etc.

Vitamin D sources:

☀️ Get more Sun: with the mantra of the day being ‘stay indoors ‘it’s becoming difficult to catch the sun. A sunny balcony, a porch, cycling in the sun or just a walk are ways that we can soak up the goodness.

☀️ Diet: Mushrooms, milk fortified with Vitamin D, eggs, fish are good sources.

☀️ Supplements:  Vitamin D supplements are easily available at your doctor’s recommendation. A small daily dose in the form of suspension or a tablet can be prescribed especially if finding the sun is difficult.

Safe sun exposure:

While sun exposure is essential to produce Vitamin D it is important to be safe whilst doing so. The duration of sun exposure depends on the amount of melanin in the skin too. People with more melanin (darker skin tones) will need longer in the sun than those with less melanin.

The recommendation is to expose at least 25% of bare skin (no sunscreens please) for at least 30 mins to the sun between 11-2 pm or longer for the morning sun for adequate exposure to UVB rays and production of Vitamin D. 3-4 times a week should suffice

Vitamin D recommendation:

The current recommended daily allowance of Vitamin D for people with preexisting normal levels is 400 to 800 international units per day. Higher doses may be suggested by your doctor if your levels are low. A blood test is generally required to determine the level of Vitamin D in your body before higher doses can be safely suggested.

Vitamin D toxicity:

Taking high doses of Vitamin D can cause toxic effects given the nature of this Vitamin. Hence it is extremely important not to take higher doses without consulting your doctor

Go ahead and get the immunity boost that you need just from soaking up the sun! Stay safe and maintain social distancing whilst you do so!