home » blog »

Me and my shadow: Is your sunshine the "right" sunshine for vitamin D production?

By Dr. Susan E. Brown, PhD

We produce vitamin D from sunlight exposure, but not all sunshine is created equal.


Only a narrow spectrum of sunlight ultraviolet radiation (UV) stimulates our body’s production of vitamin D, and it’s most intense at the equator where the sun is directly overhead. However, as you move away from the equator, UV radiation varies by season, being the most intense in the summer when the sun is high in the sky. In northern areas, the slant of the sun is such that during the winter months we produce virtually no vitamin D.

As getting vitamin D from the sun is so important, I am delighted to share with you a very simple system for estimating the Vitamin D–generating potential of your sunlight. It comes from Canadian vitamin D authority, Dr. Reinhold Vieth, who reports that all you need to do is to look at your shadow. If your shadow is shorter than you are, then you are able to produce vitamin D from this sunlight. If your shadow is longer than you are then you know you are not being exposed to that small spectrum ultraviolet radiation that allows for vitamin D production.


I tried the simple system myself here in Syracuse, New York, in mid-July:
-    At 7 AM, my shadow was much taller than I am,
-    by 11:30 AM, with the sun reaching directly overhead, it was very short,
-    by 1:30 PM, it was even shorter,
-    by 3:30 PM, the shadow was still shorter than I, but growing….
-    and by 4 PM, me and my shadow were about the same size.

From past research we know that these hours around midday are indeed the prime time for vitamin D production. Actually this little tidbit is but one part of a very impressive vitamin D lecture Dr. Vieth recently presented at a conference in London. For a YouTube video of this lecture I refer you to http://bit.ly/quUhb7.

Oh yeah, be sure to pick a sunny day for this experiment. If it is a cloudy day, you will not see your shadow at all.


You can try Dr. Brown’s comprehensive supplements in her at-home bone health program, developed with Women's Health Network. Get her exclusive formulations along with her detailed lifestyle and diet guidance, plus telephone support whenever you need it. Learn more about the Better Bones Health Package.

We created the Better Bones blog as our forum to express opinions and educate the public about natural means of supporting and improving bone health and overall wellness. As part of this forum, we sometimes discuss medical issues and medications, and their effects on bone health in general. However, we cannot advise readers about specific medical issues in this forum. If you wish to obtain advice from Susan E. Brown, PhD, about your specific bone health and nutritional concerns, please visit our Consultations page. Other specific medical questions should be referred to your healthcare provider.


September 9. 2011 09:22

Very useful thanks. Does that mean then if I can't see a shadow I am getting no vitamin D (or very little?) despite how bright it is or how close to midday?


September 9. 2011 10:49

Is there any lamp which produces Vit D3?
I worry that I do not get enough living 3 floors up in Scotland!


September 12. 2011 07:19

How long a period of exposure to the sun is recommended?


September 12. 2011 09:21

Hello Ellen,

For light-skinned individuals, approximately 15 to 20 minutes of exposure is sufficient. Unless you're extemely fair-skinned or live at very high altitude, that should not be enough to cause a sunburn. For darker-skinned persons (that is, individuals of African or Latino descent) more time may be needed, in the range of 30 to 45 minutes.

If you are very fair-skinned and concerned about burning, it's OK to do 10 minutes, cover up for an hour or two, and then do 10 minutes more.

Managing Editor

September 14. 2011 16:28

Very interesting but confusing at the same time view for years we have been told in order to prevent skin cancer we have to make sure we avoid being in the sun between 11am till 3pm, now you are telling us that is the best time for Vitamin D absorption.  Just like all the other contradictions we have been getting over the years, DO NOT EAT BUTTER, EAT BUTTER, ETC.  what are we supposed to believe???? :) Would very much apprec your comment. TKS


September 14. 2011 16:38

Hi Maria,

For nearly everything we take in, there are pros and cons. Excessive exposure to sunlight is a risk factor for cancer, yes... but so is vitamin D deficiency! There's a school of thought that argues that if you have appropriate vitamin D levels (>60) you'll become less susceptible to all forms of cancer, skin cancer among them. And, keep in mind that one key concern with respect to skin cancer (and the rationale for the caution about sun exposure from 11 to 3) is that burning your skin damages your skin. People who have experienced episodes of severe sunburn are at higher risk of skin cancer. So one of the reasons for the caution is to limit the likelihood that people will burn their skin.

For most people, the amount of time in the sun that's needed to convert the day's strongest UV rays into vitamin D is too little time to get a sunburn. There are those for whom that isn't true, though, and they might be better advised to stay out of the sun altogether and use vitamin D supplements instead. And for anyone who is considered at high risk for skin cancer (or who has already had skin cancer) it's probably best to use supplements in place of sunlight.

Managing Editor

October 5. 2011 01:57

Sunlight can never cause cancer. Instead it strengthens immunity of the lymphatic system and protects the person. It is lack of sunshine that causes many diseases. But if you visit NaturalNews.com you will learn that there is a lot of political contradicting interests behind every scientific observation to lead or mislead the public. If people become more knowledgeable, many businesses cannot thrive, because they thrive on the gullibility of the masses. Profit comes from the ignorance of the people about their health. Wearing ordinary sunglasses is good. I have done experiments with BananaLeaf and Sunshine.See my site , www.sunflowerdance.com bottom left picture. You will get inspired. Banana Leaves wrapped around a wound or a cancerous growth and exposed for 20min will have good curing effect as it brings out the toxins or bad elements inside the wound and stops further misbehaviour of cells in cancer.I cant explain it scientifically.There is no need for me to explain it scientifically. Those who want to believe can believe and get cured. It is not the only thing to get cured.One has to follow a routine of alkaline diet for a couple of weeks for any ailment.
IN Asia, people work hard in the hot sun, they should have had cancer hence, as per the wrong reasoning of some medical bla blahs.
You can do it moderately little by little and you know how much you need. It removes many blockages from the skin and therefore many toxins come out thru the opened sweatpores and body gets healthy.
Vitamin D shortage ALSO causes cancer in some persons who never go in the sun.
Sun only help, support life on earth. But due to our felling of trees and pollution of air with carbon monoxide, sunlight has become harmful also for some sensitive persons. Times are changing.
We can also change with the times instead of keeping fixed ideas.
ONE IMPORTANT THING I FORGOT with reg to bones: For my knee pain what I did was to wrap the knee by plantain leaves and tie them with the leg and expose them for 30min with head in shade! It reduces your knee pain. Pls explore Doc Brown, about this experiment! MEANWHILE THANKS FOR LOTS OF IDEAS IN YOUR SITE, I WILL GIVE IT TO PEOPLE FREELY FOR THEIR HEALTH AND WELFARE!

-D PARAMESWARAN,sunflowerdancetrust, india.,non profit association


August 11. 2014 09:27

That is a great tip particularly to those new to the blogosphere.
Short but very accurate information… Thank you for sharing
this one. A must read post!

link google plus and facebook

November 23. 2014 01:46

Recent Blogroll ...I just joined free membership and recommend it for you as well, try it and I am already getting 50,000 visitors after reading awesome ebooks shared by Admin          ----- http://free-ebooks12.blogspot.com/


Add comment


Recent Posts