Vitamin D and Sunlight and Your Health

There is an increasing volume of research being conducted about Vitamin D and sunlight as scientists discover more and more about the amazing health qualities to be found in Vitamin D. 

Search more than 200 pages on this site...
Vitamin D and SunlightSoaking up the Vitamin D and sunlight while sailing

Vitamin D and Sunlight for COVID-19 immunity

There has already been at least 20 years of Vitamin D research available for all to read. The importance of it being accepted has now really come to the fore as the world grapples with the COVID-19 pandemic.  

Vitamin D is essential to a healthy immune system

Our immune systems defend our bodies from any strange, invading organisms and elevate our protective immunity while also maintaining existing tolerance levels. 

A Vit D deficiency affects this immune system in ways that have become clearer in the more recent years, showing especially an increased susceptibility to infection and repeated illnesses. It is now clear that vitamin D has important roles in addition to its classic effects on calcium and bone homeostasis.

As the vitamin D receptor is expressed on immune cells (B cells, T cells and antigen presenting cells) and these immunologic cells are all capable of synthesizing the active vitamin D metabolite, vitamin D has the capability of acting in an autocrine manner in a local immunologic environ.

Vitamin D can modulate the innate and adaptive immune responses.

A deficiency in Vit D is therefore associated with

  • increased autoimmunity
  • increased susceptibility to infection

As immune cells in autoimmune diseases appear to be hugely responsive to the ameliorative effects of vitamin D, the benefit of supplementing Vitamin D in those that are deficient, may extend beyond the well known effects on bone and calcium homeostasis into addressing autoimmune disease, or for COVID-19 as we are seeing.

Sunlight: optimum Vitamin D Source 

The optimum source of Vitamin D for humans is believed to be sunlight and what's more, its absolutely free! No prescription required.

Maybe this explains a bit about why it's remained relatively unknown or under-researched for so long, as the big pharmaceuticals can't sell sunlight to us.

However, they can sell sunscreen, and so for a few decades now we have all been told to avoid this wonderful resource of health and block out the sun's rays. 

But it's not all as easy as just stopping the use of sunscreens and exposing yourself to the sun's rays to take advantage of this valuable nutrient.

The levels of Vit D in foods is almost none – the idea that you can eat enough Vit D to protect yourself from illness is a little fanciful. Vitamin D3 is produced by the action of sunshine on the cholesterol layers under the skin. 

There is however, far more to it than that and the following highlights some of the truths around Vitamin D and sunlight and our health.

Vitamin D and Sunlight Truths

  • Vitamin D is created through your skin by exposure to UVB rays from either natural sunshine or UVB lamps (not UVA which is contained in sunshine as well as most tanning beds lamps)
  • UVB rays are also weakest in the morning and evening and strongest when most direct. ie midday and unfiltered by cloud, smog, glass or such
  • UVB rays weaken the further you are from the equator. ie. they are no longer as direct
  • To generate the same amount of vitamin D, dark skin pigmentation requires 20 - 30 times more exposure to sunlight than fair-skin pigmentation. Hence the prostate epidemic with black American men mostly shows up with a vitamin D deficiency
  • The health benefits obtained from vitamin D are numerous and include building strong bones and nervous system as well as helping to prevent such health complaints as osteoporosis, depression, prostate cancer, breast cancer, diabetes and obesity
  • It is impossible to generate too much vitamin D in your body from sunlight exposure. Your body will self-regulate and only generate what it needs. Overdoing the sunlight exposure results in sunburn, which is your natural body's mechanism to tell you to stop and obviously not a good idea!
  • There are some good sources of vitamin D2 to be found in food and supplements but the best source of vitamin D3 is through sunlight
  • If there is a need to rebuild the body's bones and nervous system due to an identified chronic vitamin D deficiency you cannot do this overnight. Months of vitamin D supplementation as well as regulated sunlight exposure may be required

So get outdoors for vitamin D and sunlight benefits!

So if sunlight exposure is really one of the most powerful healing therapies available to us in the world today, it must also be said that sensible exposure to natural sunlight can be one of the simplest, easiest and yet very important part of improving your health.

How beautiful that we can get to enjoy that feel-good sunshine 'pill' in the outdoors and not have to take drugs, undergo surgery or subject our body to immune suppressing chemical treatments!

And of course vitamin D and sunlight are free of charge.


Dr. Michael Holick

The Vitamin D Society

New! Comments

Have your say... please leave me a comment in the box below.
Was this page helpful? Please share it. Here's how...

Would you prefer to share this page with others by linking to it?

  1. Click on the HTML link code below.
  2. Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.