What Does Vitamin D Do

What does vitamin D3 do?

What Does Vitamin D Do

Vitamin D supplement pills in a close up shot.


Many people have asked about vitamin D and if it can benefit them.  What does vitamin D do?  Is vitamin d3 the same as vitamin d2?  We’re going to go over all of these questions and more right here.  We will Look at the different types of vitamin D and whether they work or not, and some that can even hurt you.  That’s not all I have to say about it either, so pay attention!


About Vitamin D


Known as a fat soluble prohormone (enhances hormones), vitamin D is a steroid vitamin.  Most people know about it’s encouragement of the metabolism of phosphorus and calcium in the body.  But that’s not all it does as you will see later.  It enters the body through sunlight, proper nutrition, and supplementation.  Here are several different forms that we know of:  Vitamin D1, D2, D3, D4, and D5.  The ones that I’m going to talk about today are D2 (ergocalciferol) and D3 (cholecalciferol).


Is vitamin D3 the same as vitamin D2?  There is a lot of confusion about the effects of D3 vs. D2.  Most experts that don’t work for a pharmaceutical company agree that D3 is what your body needs most.  It is the natural version and is better absorbed by the body and much more potent, as well as inexpensive.  You see, vitamin D2 is not natural to humans.  It is produced through ultraviolet exposure of foods and irradiating fungus and plant matter.  This process was patented by the drug companies around the 1920’s and remains the main source of vitamin D in prescription vitamin supplements.  To be fair, it was effective in it’s use of curing rickets in the past, but there is now newer research about the matter and D3 is what you want.


Is vitamin D3 really better?  YES!  Vitamin D3 is converted 500 times faster than vitamin D2.  It also has a longer shelf life and is more easily stored in the body.  Cost is one other thing to look at and –you guessed it– Vitamin D3 is much more affordable since you don’t need a prescription for it!  You can even get some by simply walking outside.  Your body naturally makes vitamin D3 on it’s own!  The key is exposure to the sun.  That’s right, our skin absorbs the UV-B that is in normal sunlight and converts it into vitamin D3.  It’s recommended that you get healthy amounts of sunlight to keep your levels at an optimum level.  Just don’t over do it and get burned!


Vitamin D3 Benefits


It is now widely known that vitamin D3 benefits many aspects of your heath.  There are 30,000 genes in the body and vitamin D3 influences over 2,000 of them.  Every organ and every cell in your body has receptors for vitamin D.  This means that it is involved with core processes everywhere in the body.  It is also used by cells to regulate genes.   Wow,  what a powerful vitamin!  For starters it has been shown to:


  • lower your risk of diabetes
  • slow signs of aging
  • reduce tumor growth
  • help prevent cancer
  • enhance immunity to microbial infections
  • reduce your risk of multiple sclerosis
  • up-regulate cathelicidin, a naturally occurring broad-spectrum antibiotic
  • strengthen bones
  • prevent heart disease
  • prevent the flu and colds
  • prevent inflammation
  • optimize your weight


The list above is only a small example of what science is finding out about the effects and benefits of vitamin D.  Lets take a look at how it can help the immune system.  Vitamin D is a potent immune system modulator. The vitamin D receptor (VDR) is expressed by most cells of the immune system, including T cells and antigen-presenting cells, such as dendritic cells and macrophages.  It is a very strong antibiotic because it increases antimicrobial peptides.  Over a century ago, before antibiotics and other medicines were discovered, TB, lupus, and psoriasis were treated with sunlight by sitting the patient in a solarium.  No joke, and most actually got better!  Remember when I told you that sunlight reacts with the skin to produce vitamin D3 naturally in your body?  This is just one example of that.  Here ore some other examples of what D can have positive effects on:


  • Seizures
  • Fertility
  • Age related macular degeneration
  • Myopia
  • Pre eclampsia (a complication in pregnancy)
  • Alzheimer’s disease
  • Asthma
  • Cystic fibrosis
  • Migraines
  • Depression
  • Schizophrenia
  • Athletic performance


Vitamin D3 Dosage


What kind of blood test do I take for vitamin D3 levels?  Before going out and getting a crazy amount of vitamin D3 supplements,  you should perform the 25(OH)D test.  Doctors have been known to order a 1,25-dihydroxyvitamin D test. This is the wrong test as it cannot determine vitamin D deficiency.  So, again you need to make sure that you get the 25(OH)D test also known as the 25-hydroxyvitamin D test.


As I’ve looked around, the best test out there is called the DiaSorin test.  This is considered the “gold standard” in testing because it is what all research on vitamin D has been based on.  If you are having trouble finding someone that does this test it’s OK, I recommend that you go to LabCorp and ask for the 25(OH)D 25-hydroxyvitamin D test.  Next, make sure that it is calibrated with the DiaSorin measurements and standards.  They should be, but just make sure! It’s important!  Note:  I have heard that Quest Diagnostics labs are giving bad results so don’t go there.


How do I know what dosage is right for me?  The optimal range for most people is 50–80 ng/mL.  This is where you want to keep it at.  The catch here is that not everyone is the same.  People that have significant deficiencies will need way more supplementation then the average healthy individual.


Researchers found that a supplemental dosage of 9,600 IU of vit D per day enabled 97% of patients to reach 40 ng/ml in their blood.  The National Academy of Sciences states that 4000 IU/day of vitamin D is safe for daily use by adults and children nine years and older.  They also revealed that 1000-3000 IU/day was safe for infants and children through age eight.


Vitamin D3 overdose symptoms:  It is possible to overdose on this!  Although many have over reacted to the possibility of overdose, it is a danger that you should take seriously.  The vitamin D blood toxicity level is 200 ng/ml.  Symptoms include:


  • Nausea
  • vomiting
  • Loss of appetite
  • Weight loss


Diagnosis of an overdose can be quite difficult because of the few and rare symptoms that identify it.  That’s why it is so important to get your blood tested for D levels and use the recommended dosages that you and your doctor agree upon.


Enhanced by Zemanta
  1. TedHutchinson

    While I agree that it’s important to regularly test 25(OH)D levels, I see little if any value in doing so BEFORE using an effective amount of vitamin D3.
    We are all aware that human skin creates 10,000~20,000iu of vitamin D3 given full body non burning summer sun exposure and we are all aware that it’s difficult to obtain more than 500iu from food or supplements therefore in practice EVERYONE who isn’t able to lay near naked in the midday sunshine regularly will have lower vitamin D3 status then human DNA evolved to work best with.
    The evolutionary advantage that pale hairless bodies provided away from the Equator surely was the increased ability to create Vitamin D3 in order to STORE D3 in tissue cells. Circulating Vitamin D3 in plasma has a half life of 3 weeks, while vitamin d winter in the UK lasts from Oct through to the end of Feb. (roughly 7 half lives)
    In winter therefore it is necessary to supplement first and test later.
    We know up to 10,000iu is safe and may be required by many but if we all start with 4000iu/daily/vitamin D3 for 8~12 weeks and THEN test 25(OH)D we will know how our body responds to 4000iu/daily.
    Confirming you are vitamin d insufficient in a country and time of year when everyone else is vit d insufficient (apart from those with regular access to UVB tanning lamps or who are currently taking effective strength supplements) is simply a waste of time and money.
    We have to get our priorities right.
    We must put the safety and health of people first.
    999 out of 1000 people are vitamin D insufficient, so testing all those people is simply a money generating exercise for the industry and a pointless waste of time and money.
    Only after you have been taking effective vitamin D repletion measures for a reasonable amount of time is it necessary to check 25(OH)D to see how your body has responded and how much more vitamin D you may require to attain/maintain the 60ng/ml level at which human milk is a vitamin d complete food for human babies.

    • admin

      Hello again Ted! Very well said. I do have to agree with you. My train of thought was that being tested before starting supplementation would give one a starting point and a goal to work toward. However, it is true that most not living on or near the equator (and even them) are destined to have very low levels of vitamin D. Just to be clear for my readers- It is recommended that if you use vitamin D3 supplements, you should probably keep your dosage at around 4,000 to 5,000 UI per day for an adult. Keep the great comments coming!

  2. TedHutchinson

    While the situation MAY be different in the USA, the idea people in the UK should only use “dosages that you and your doctor agree upon.” is laughable.
    I’ve certainly never met a UK doctor with any clue about Vitamin D3 usage or up to date with current Vitamin D3 research.
    The idea the average UK doctor know best or even anything relevant about Vitamin D3 is mistaken.
    The average UK GP appointment lasts less than 10 minutes. I may have a working knowledge of recent Vitamin D3 research but I’d find it difficult to educate or convert most UK GP’s in the time available.
    Most UK GP’s are still using D2 and haven’t a clue about the appropriateness of 25(OH)D testing or the requirement for effective amounts of vitamin D3.
    If you value your health then you must take responsibility for your own body and not delegate that responsibility to lazy, negligent health professionals who are clearly failing to keep up to date with current medical research.
    I certainly agree you should discuss the vitamin D3 issue and the need for 25(OH)D testing with your UK GP. But the purpose for that is to educate your GP, to attempt to bring them up to date with the most recent research but you will probably need to get your 25(OH)D test from one of the US postal providers.
    Grassrootshealth and Vitamin D Council are charities that offer a postal testing service at reasonable cost.

    • admin

      Hello Ted, I agree. It is laughable that a large percentage of doctors will not take the time to honestly review the current data. My general practitioner here in the states always says “I can’t just recommend these treatments. Most of them are scams. I need DATA!” Well when I gave him peer reviewed double blind placebo data, he just ignored me! That’s one of the reasons why I decided to be responsible for my own health.

      I will say that My son’s Liver specialist did recommend Milk Thistle, and I was delighted to find out that he is a reasonable and open minded professional. Thanks for your insight Ted, and I hope to see you around!

    Twitter not configured.