Sunday, March 23, 2014

Would you be deficient in Vitamin D if you are exposed to sun regularly?

The sun, used to be our friend since humans evolved more then 2.5 million years ago. The sun was regarded as our essential source of Vitamin D, apart from animal based foods. All living things on the planet, depend on the sun in order to survive and thrive optimally. Plants, animals, and our ancestors who lived for countless generations. Sun was believed to be our friend, our main source of Vitamin D, which is a critically important hormone needed for bodily functions, development, combat diseases and so many other benefits. 

Fast forward to present day, particularly since sunblock products were made commercial, and majority of us have been hardwired to believe that sun is harmful to our body, and we need protection from this life sustaining source, and sunblock is the way to go, to ensure we do not develop skin cancer or somewhere along that line. We were told that the sun is stronger now, compared to thousands or hundreds or years ago. 

That may be true, due to ozone depletion (thanks to humans killing our own planet earth), but the question which all of us should be asking, "How much sun exposure do you get weekly?" We all have been told that sun is bad and it causes skin cancer, and we should avoid it as much as we should. Put on sunblock lotion whenever we are outside under the sun, and avoid being exposed during midday as it gets stronger. How much truth is that? The truth is, not even a fraction. I think the question we should be asking ourselves, "How does our ancestors few generations ago (80-100 years or longer), lived?" Did they cover up the whole body and put on sunblock lotions? Did they suffer from sun phobia just like most of us? Do they even know how important Vitamin D is for their health when they really living their lives? The answer is NO. Same thing with counting calories or joining a gym membership. None of our older ancestors know about calories nor the need for so called 'exercising' in a gym. But guess what, they were a lot more healthier then our current generation, extremely low rates of diseases, and diabetes and obesity is virtually none existent. Heart disease and cancer barely even exist in most countries during those period, not to mention skin cancer which most of us are so afraid to be expose to the sun. 

As I wrote about deficiency of Vitamin D in my previous posts, I would like to clear up some of the confusion by some people I met recently. I will reveal in this post how exposure to sun regularly could cause deficiency in Vitamin D. How is that so? You must be asking, how could that possibly be, if one often spend time under the sun? Well, let's talk about UVa and UVb. As long as I could remember, we have been told that UVa is good for us, and we should send minimal time under the sun only in the early morning. I promise you, you will not witness many people spend time under strong sun around midday (12-3pm). But, you could see tons of people holding on to their umbrellas while outdoor during lunch time. I've personally seen guys doing it, and i could not believe my own eyes. Seriously? 

Let me get this straight. The morning sun, is primarily UVa, which gives you the tan. It does not provide you the actual D3 which your body needs. Now, if you spend most of your time in the morning under the sun, you are not getting Vitamin D3 which most people are suffering from low level of this hormone. Don't believe? It's easy. Try spend 2 weeks straight every morning under the sun for maybe 20 mins each day (with minimal clothing and no exposure during midday) and perform a 25 Hydroxy Vitamin D3 test. Do the tests before and after the 'sun-exposure period'. Do not change any other lifestyle nor diet patterns. You may be surprise your Vitamin D3 level reduced after that 2 weeks stint. 

What about miday sun exposure? What about UVb? Isn't it bad and harmful to our skin? I know it is hot in certain places or cities during summer or dry season in asian countries. Would I get sun burn if exposed to such hot weather during midday? The answer is YES. But, the key here is to assess yourself, and find out the duration of time where your skin turn 'pinkish' while under the sun during midday. For instant, if you spend 40 mins under the strong sun with minimal clothing and your skin turn 'pinkish', that is your body telling you that it is the threshold of Vitamin D absoption. Now, studies have shown that our body may need as little as half of the dosage of what our skin is telling us. The 'pinkish-skin' test would be a good indicator. In this case, half dose of Vitamin D3 from the sun would be 20 minutes with minimal clothing. If your maximum threshold is 60 minutes, then your body needs around 30 minutes. The darker your skin is, the more sun exposure you need, as the layer of tan on your skin protects you from getting sunburn. It's in fact the best natural sunblock one can get for your own skin. 

How can you confirm the midday Vitamin D absorption? It's simple. Same thing apply with how you perform the UVa early morning 2 weeks test. Do he same thing, but this time, spend your time daily expose to the sun from around 11am-3pm. Anytime within this hours, and depending on your skin tone color, do a retest of your Vitamin D3 level, you will be suprised by what the blood test tells you (if your diet have adequate cholesterol and fats, will talk about that shortly). 

For the folks who stay far away from the equator, luck is not so much on your side. Unless your diet is loaded in Vitamin D3, which primarily consists of animal based foods including meats, seafoods and eggs. If you are a vegan, your risk of Vitamin D3 defficiency is extremely high, especially very minimal midday sun exposure. I've seen myself most vegans spending more time indoors looked pale and sick. But of course, there may be a minority of vegans who could be healthier then their counterparts. 

Now, let's talk about diet role in Vitamin D3 absoprtion and conversion. What's the relationship between diet and Vitamin D3? Does anyone realize the your body can only absorb and convert UVb from the sun and make it into a usable form of Vitamin D3, if your body has adequate amount of healthy fats and dietary cholesterol? 

Some people may know that getting Vitamin D from the sun is enough as long as they spend some time outdoor. The raw material to utilise and convert the UV from the sun to usable Vitamin D3, is cholesterol, and also significant amount of fats. All of these, are from dietary diet, the foods we eat. Cholesterol has been
wrongly demonized by the medical and food industries, this life sustaining molecule is so crucial, that without it, we will vanish and died off. 

I want to talk a little bit about infant, breastfeding and the role of Vitamin D3 deficency. We are facing more and more breastfed infants suffering from Vitamin D defficiency. Why is that so? Studies (journals below) have shown that more and more infants including breastfed babies are deficient in Vitamin D. About 50-60% of European American women are deficient in Vitamin D during later stage of pregnancy. Approximately 90% of African American women are deficient in Vitamin D during the same stage of pregnancy too. At birth, those infants retain that deficiency from the mothers as shown in these studies. If the deficiency continue in following months after birth, the infants Vitamin D level will be low even if breasfed from the mothers. To tackle this issue in a smarter way, enhance the mother's Vitamin D level optimally, thus breast milk contains higher level of Vitamin D and the infant will benefit at the same time. Bear in mind, feeding your infant so called "Fortified Vitamin D" infant milk formula WILL NOT enable the baby to have improved level of this crucial hormone. In fact, infants who were fed infant milk formula, is severely deficient in Vitamin D level. A more important question, "Is milk a good source of Vitamin D?" the answer is YES and NO. If the infant is from birth until maybe 2 years old, mother's milk is an ideal source. But, for kids or adults, it would be ridiculous to drink any commercial milk products of somewhere between maybe 5-20 glasses daily to meet recommended daily allowance (RDA). 

Finally, the question everyone would be asking, "What is the best source of Vitamin D?". "Is diet and foods adquate for our Vitamin D requirement?".  Below are some of the frequently asked questions by the folks I met, and my honest answers to you.


What is the best source of Vitamin D?
The sun, but certain foods from diet could help optimize the level of Vitamin D in the body. Population staying away from the equator and minimal sun exposure, depends primarily on foods high in Vitamin D such as organ meats and seafoods.

Is diet and foods adequate for our Vitamin D requirement?
In most cases no, unless you diet is somewhat similiar to Eskimos (Inuit), eating wild caught seafoods, seals, fish livers, etc.

Would too much of sun exposure (even during midday) causing Vitamin D toxicity?
NO. Our body is intelligent enough to auto-regulate the absorption of this hormone from the sun, shutting off the mechanism but you may get sunburn from long hours of exposure. Do observe the 'pinkish' color on your skin when you spend long hours under a hot sun.

Does everyone requires the same amount of sun exposure? 
No. Different people with different skin color requires more or less amount of sun exposure.

Can I supplement with Vitamin D from over the counter products?
Yes you can, but it would be a poor choice as most of these products are synthetically made, and you may wasting your money, instead of getting it free from the sun.

Does sun exposure causes skin cancer?
NO. Vitamin D from the sun protects us from skin cancer, and other form of cancer too.

Can you be Vitamin D deficient even if regularly exposed to morning sun?
YES. The goal is getting UVb exposure during midday (11am-3pm), but depending on the area where you stay. As the sun gets closer the the surface of the earth during midday, the UVb level increases, but it diminish as evening approaches from 4-5pm onwards. 



Vitamin D defficiency Journals (Pregnancy, Breasfed & Infants)
http://jn.nutrition.org/content/137/2/447.full
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3427250/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3206624/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3540805/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3629265/







1 comment: