Which Vitamin D to Buy?

First of all, supplements are available as Vitamin D2 (Ergocalciferol) or Vitamin D3 (Cholecalciferol). The 25-Hydroxy Vitamin D test determines the combined level of Vitamin D2 and D3. Skin of animals, including humans synthesize the D3 from the Ultra Violet B (UVB), while plants synthesize D2.

To read why we need Vitamin D, and what may cause deficiency even when you think you are getting enough sun, see my previous post here.

Vitamin D2 or D3?

For more than 70 years, D2 has been administered to children and adults to successfully increase Vitamin D level in the blood. In last few decades, some scientific studies suggested that D3 is more effective than D2 as our skin is anyway supposed to synthesize D3. However, more recent studies suggested that D2 can be as effective as D3.

I didn’t go to medical school, but my doctor didn’t have a clue either, so I had to do my own research. I haven’t come across any study or article that would suggest D2 is better than D3. Please point me to one if there is out any. Does that mean when possible take D3 instead of D2? I would like to think so.

Here is a compilation from an MD, Dr. Christensen on why D3 over D2 [Reference]:

• UVB light from the sun strikes the skin, and humans synthesize vitamin D3, so it is the most "natural" form. Human beings do not make vitamin D2, and most healthy fish contain vitamin D3.
• Vitamin D3 is the same price as vitamin D2.
• Vitamin D3 may be less toxic than D2 because higher concentrations of D2 circulate in the blood when consumed (compared to vitamin D3). It does not bind as well to the receptors in the human tissues compared to vitamin D3.
• Vitamin D3 is the more potent form of vitamin D, which is a potential benefit. For example, obesity tends to lower blood levels of vitamin D, so a more potent form is needed.
• Vitamin D3 is more stable on the shelf compared to D2, and is more likely to remain active for a longer period of time and when exposed to different conditions (temperature, humidity, and storage). This is perhaps why the amount of vitamin D2 in certain fortified food products have been significantly lower than that advertised on the label in numerous instances.
• Vitamin D3 has been the most utilized form of vitamin D in clinical trials, and there have only been a few clinical trials of vitamin D2 to prevent bone fractures in adults.
• Vitamin D3 is more effective at raising and maintaining the vitamin D blood test (again, D2 binds less tightly to the vitamin D receptors in the body; therefore, D2 does not circulate as long in the body, which means it has a shorter half-life).

Choosing the Right Supplement

• D2 and D3 are fat soluble and is best taken in a gel capsule form. So, stay away from tablets.
• D3 supplements are derived from animal base, some of D2 are plant based. So, vegans may prefer the plant based D2
• It appears that USA Food and Drug Agency (FDA) has not approved D3 yet. So, for high dose of Vitamin D, where prescription is required, you may only get D2. However, I found a few high dose D3 available without prescription too.
• Go with a brand you trust. If you are new to the vitamin world, like me, I had to do some more research.

Selecting the Product to Buy

Based on the reviews I narrowed down to the following products:

• HealthyOrigins - Got the best deal on Soap.com with free 2-day shipping and 15% discount code: ANXX6983. The shipment promptly came in the next day!
  
• ProHealth Vitamin D3 Extreme™
• Biotech Vitamin D3
• Now Foods Vitamin has D-2 and D-3 products
• Deva Vegan Vitamin D2

Taking the Capsule

Check with your doctor, mine suggested to take after full meal, otherwise it can upset stomach.

Under Sun, but no Vitamin D!

Do you think you get enough Sun? You may have to think again! 

I sit in an office with huge windows facing the Sun all day long and my office is in the so called “sunny” California. I figured I was getting enough sun-light for my body to make Vitamin D. But, my recent blood test showed that I am grossly deficient. MayoClinic has a short, but good article on why our body needs Vitamin D. With this post I am hoping to increase the awareness of growing deficiency in VitD among people around the world.

Sun-light and Deficiency in VitD

Enough sunlight, then why the deficiency, you ask? There can be several reasons. I am not a medical professional, but the interesting ones I found in my research:

• Office windows are usually tinted, which blocks all of UVB (required by skin to synthesize VitD) and blocks only some of UVA (can be very harmful and causes aging of skin - read the 911skin report)
• Sunscreen, even SPF 8 blocks 95% UVB [Reference]
• If you are not in a tropical country, during winters sun is at an angle, such that all or most of UVB cannot penetrate atmosphere. But, all the UVA may still make it’s way.
• Other medical conditions
  

Proper use of Sunscreen

You have to use your own judgement on when and where to apply the sunscreen, but the general recommendations I found on internet forums that actually make sense:

• Always protect your face
• For rest of the exposed body parts, don’t apply sunscreen inside home. Go out in the sun and apply sunscreen after 15-20 mins. Darker skin or people with tan may need more time. Basically, apply sun screen once your skin feels warm, but before it gets the burn.
• Always wear sunscreen near the sea beach, as white sand and water may reflect sun rays and UVA will burn skin faster than your skin can make VitD.
  

Are you Deficit in VitD?

Ask your doctor about the 25-Hydroxy Vitamin D blood serum test, and if possible get the VitD level tested during regular checkups, at least once a year. Preferred frequency of test seems to be once after summer, and once after winter. Check with your insurance if it will cover the test, some don't seem to cover the VitD test.

Sources and Supplements of VitD

There is very little Vitamin D in food sources and it may not be possible to get the daily value just from food sources. See the food chart for VitD provided by National Institute of Health, Office of Dietary Supplements. 

So, if you are not getting enough UVB, then you need prescription or over-the-counter Vitamin D supplements. Now, there are 2 types of Vitamin D supplements, D2 and D3. My PCP didn’t seem to know much, so I had to research online for days to understand the difference and to figure out the right one for me. Look for my research findings in my next post.