Do You Get Vitamin D Through a Glass Window?

Here’s why sun-bathing through your glass window is giving you no vitamin D benefits

Updated14 May 2018, 06:43 AM IST
Chew On This
3 min read

Are you blissfully happy to soak in the sun through the rolled up window of your car and think that the warm, peeking sun is blessing you with glorious beams of vitamin D?

Sorry to pop your bubble but you’re highly mistaken.

For starters, the sun doesn’t give you vitamin D; your body manufactures it when certain wavelengths of sunlight, the ultraviolet-B rays (UVB) activate a chemical called 7-dehydrocholesterol within your skin.

It’s a truth universally acknowledged that behind all aches and pains there is a deficiency. Well, mostly. Several studies have proved that in our metropolitan cities vitamin D deficiency is the latest epidemic - nearly 85% people in urban India have this deficiency and most of them don’t even realise it.

So if you’ve been waking up tired, have knees that creak and dealing with unexplained aches, are always PMS-ing but soaking up the rays of the sun through a glass window - you might feel the warmth of sunlight but it’s totally deceiving. The component of sunlight needed to produce vitamin D is getting blocked through the glass.

3 Reasons You Might Not Be Getting Vitamin D Even In the Sun

(Photo: iStock)
(Photo: iStock)

1. Suntanning Through Glass Can Give You Cancer

The UVB rays which help your body make vitamin D get cut through glass but not the harmful UVA rays - these penetrate through the skin more deeply than UVB and can cause wrinkles, skin cancer and photoaging.

In fact a study published in Medical Hypotheses suggested that indoor workers who sit next to glass windows and are constantly exposed to the sun have a higher chance of melanoma because of the constant exposure to UVA light. So watch out!

2. You Lather Too Much Sunscreen

(Photo courtesy: Tumblr/@Gifbay)
(Photo courtesy: Tumblr/@Gifbay)

You need at least twenty minutes every day of a little straight-up sunshine to produce vitamin D but sunscreens effectively block the UVB rays which help you synthesize vitamin D.

Now this makes little sense for us in India because very few people put enough sunscreen to block all UVB light, or they use sunscreen irregularly, so sunscreen’s effects on vitamin D might not be that important

3. Air Pollution In Your City

Delhi folks, this is important for you.

Our body can produce 10,000 to 25,000 IUs of vitamin D in a day when exposed to proper amounts of sunshine. But the rising levels of carbon particles in air restrict the penetration of the important UVB rays into the atmosphere diminishing the production of vitamin D even if you stand under the sun without a sunscreen.

When’s the Right Time To Get the Sunshine Vitamin

(Photo courtesy: Tumblr/@P5Art) 
(Photo courtesy: Tumblr/@P5Art) 

UVB rays from the sun reach us most when the sun is high in the sky, so 10am-2pm is ideal in most months. In summer, this period is extended.

When the sun’s rays are at too much of an angle, as in the mornings and evenings, the atmosphere blocks the UVB wavelength.

The skin around your eyes and face is thinner than other areas and pretty sensitive to premature aging as well. So take a walking break from office before lunch, use your shades, roll up your sleeves to get the maximum benefit from the sun.

Also, vitamin D deficiency can be made up through some foods (especially oily fish), fortified foods and supplements.

For fair-skinned people, a short exposure to the summer sun once a day before your skin turns pink is enough for a day’s supply of the sunshine vitamin.

Dark-skinned people need at least twenty minutes of exposure every day because melanin, the substance in skin that makes it dark “competes” for UVB before it kick-starts the body’s vitamin D production.

Also Read: Are Daily Vitamins a Total Waste of Your Time and Money?

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Published: 25 Feb 2016, 02:12 PM IST
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