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You'll find everything you want to know about vitamin D right here.
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Best way to get it? Sunlight! Nature's own prescription.
Next best way? Supplement vitamin D3.
It's better than Health Insurance and costs less than $2 per month!
Alex St Clair
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History of vitamin D RDA
New Vitamin D RDA 2010
Is 600 IU of vitamin D enough?
Consequences of new Vitamin D RDA
Do we need a vitamin D RDA?
Safe Upper Limit of vitamin D
Vitamin D RDA to be corrected
Vitamin D3 Capsules (5000 IU)
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The earliest official vitamin D recommendation in the USA was published by the National Defense Research Council's Committee on Food and Nutrition in the late 1930's. The recommended daily amount was 400-800 International Units (IU) for men, women, adults, children and infants.
In 1993, the European Union published an RDA for vitamin D of 5 micrograms (200 IU).
In 1997 the US Institute of Medicine (IOM) set what they called an Adequate Intake level for vitamin D, because they had insufficient evidence to set a vitamin D RDA (Recommended Dietary Allowance).
Up until November 2010, these were the Vitamin D Adequate Intake (AI) recommendations in force for men and women, adults, children and infants:
|Age in Years||Vitamin D AI (IU)|
|Less than 50||200|
The main concerns of the IOM seem to have been the prevention of rickets in children and osteomalacia in adults, and the reputed toxicity of vitamin D in excess. This would have reflected the state of mainstream knowledge about vitamin D - in 1997.
On 30th November 2010 a new report was issued by the IOM, showing, for various age groups, their estimates and recommendations for
The IOM's recommendations are summarized below:
|Age||Daily Vitamin D, in IUs|
|> 70 Yrs||-||400||800||4000|
The IOM's recommendations apply to all adults, irrespective of whether they are male, female, pregnant or breastfeeding.
The IOM does not think it necessary to distinguish between the vitamin D requirements of a 10 kg small child and a 100 kg adult. The same RDA applies to all.
It is hard to reconcile the newly published recommendations of the IOM with modern research on vitamin D. This research links low vitamin D with cancer, heart disease, diabetes, multiple sclerosis and many other major and minor diseases.
The amount of vitamin D required to protect against these conditions is much greater than that required for protection against rickets and osteomalacia.
The IOM does not seem to take these new facts adequately into consideration, even though they now recommend 600 IU for younger adults, instead of their previous benchmark of 200 IU.
The main problem appears to be
The IOM targets a very low vitamin D blood level of 20 ng/ml - instead of 50-65 ng/ml indicated by recent vitamin D research.
Why is this? Well, let's see what the IOM says about it:
Although serum 25OHD level cannot be considered a validated health outcome surrogate, it allowed comparison of intake or exposure with health outcomes. Newer data also allowed the simulation of a requirement distribution based on serum 25OHD concentrations. A level of 16 ng/mL was consistent with the intended nature of an average requirement, in that it reflects the desired level for a population median - it meets the needs of approximately half the population. Moreover, benefit for most in the population is associated with serum 25OHD levels of approximately 20 ng/mL, making this level a reasonable estimate for a value akin to "coverage" for nearly all the population. Available data were used to link specified serum levels of 25OHD with total intakes of vitamin D under conditions of minimal sun exposure in order to estimate Dietary Reference Intakes.
Now I hope you enjoyed reading that more than I did! But what exactly does it mean?
I think what they are trying to say is this:
A vitamin D blood level of 16 ng/ml would be enough for half the population, but for nearly everyone to have enough, the level needs to be 20 ng/ml. From this we can estimate how much vitamin D people need to take, if they do not get much sunshine.
Now if the IOM were right about 20 ng/ml being an appropriate target blood level, then 600 IU would be a reasonable vitamin D RDA, at least for young adults.
But is the IOM aiming at the right target?
We believe that 50 - 65 ng/ml is a more appropriate vitamin D target level. This is a critical point, so let's be very clear. The main reasons are:
Let's consider point 1. People who have high levels of vitamin D seem to have lower risk for dozens of diseases. It appears that vitamin D exerts a protective effect.
But vitamin D skeptics are quick to point out that there is an alternative explanation: it is possible that high vitamin D is not the cause of that protection, but that something else causes both the protection from disease and those high vitamin D levels. If this explanation is correct, then taking more vitamin D will not reduce your disease risk.
Scientists are busy researching this very issue, but since it takes a long time to prove or disprove causation, we will all have to wait many years for the outcome.
So yes, we could just wait, but by the time causation has been proved, some of us might have died from one of those diseases! And vitamin D might have prevented it.
Why don't we all maintain a vitamin D blood level of 50 ng/ml while we wait for the proof? What risks would we run?
Well, from point 2 above it appears that "high" vitamin D levels are in fact the natural levels that the human race has experienced, and adapted to, throughout most of its existence.
So there is apparently very little or no risk involved for a healthy person to maintain a vitamin D level of 50 ng/ml or higher, only a huge potential benefit, not yet fully proven.
This absence of risk is confirmed by thousands of people who have maintained this vitamin D blood level for several years by supplementation, without a single reported case of harm.
That is why many vitamin D researchers think that 50 ng/ml is a much more appropriate target vitamin D level. If you accept this target, you will almost certainly have to take much more vitamin D than 600 IU to reach it, unless you frequently expose most of your skin to direct sunshine.
The worst that can happen is that the vitamin D skeptics might be proved right and scientists, having completed their research, report that supplementing vitamin D does not help prevent disease.
The best that can happen is that by supplementing vitamin D3 we might be able to avoid many serious diseases, lead full lives in good health, and fall asleep for the last time at a ripe old age of 99 or so. (No, seriously, you would have to exercise as well!)
These are not equally likely possibilities. By far the more likely outcome, because there is already so much evidence which points this way, is that supplementing Vitamin D will be confirmed as a powerful way to prevent many diseases.
But if scientists do discover that something else causes both low disease incidence and high vitamin D levels, it will very likely be sunshine! After all, sunshine is the only thing we know of (besides vitamin D supplements) that actually raises vitamin D levels.
That is why I recommend that you raise your vitamin D level first by increased sun exposure, and only then by supplementation. See our guidelines for safe sun exposure.
Considering their silence on vitamin D for the past 13 years, the IOM's latest pronouncement is a major disappointment.
Most medical doctors, nutritionists and dieticians are only vaguely aware of the latest vitamin D research, and don't have time to put it all together. So they just rely on the recommendations of their medical institute.
Because of these new recommendations, those health professionals will continue to believe that vitamin D deficiency is a relatively rare condition, easily corrected by a small (and ineffective) dose of vitamin D.
This is most unfortunate for hundreds of millions of people around the world who are already suffering from the consequences of chronic vitamin D deficiency - and will probably continue to do so.
In a way, it is a pity that the IOM has published a vitamin D RDA at all. It oversimplifies a complex issue.
Vitamin D is more of a hormone than a vitamin. With a hormone, you first establish the healthy (ideal) range for blood levels, then you measure the individual's blood level. Only then can you decide how much of that hormone the person needs to take, if any.
Individual needs for oral vitamin D vary widely, and these variations often cannot be predicted. Sunlight exposure makes a complex issue even more complicated.
To maintain a healthy vitamin D level of 50 ng/ml, different people may require anything from 0 to 20,000 IU of oral vitamin D3 per day. If you set an RDA, wherever you set it will be wrong for most people!
(Most adults can maintain an optimum vitamin D blood level of 50 ng/ml by getting between 4000 and 8000 IU of vitamin D daily, from all sources.)
This upper limit is intended to reflect the maximum daily dose that would be safe for almost everyone. It is often referred to as a Safe Upper Limit.
The revised safe upper limit from the Institute of Medicine is now 4000 IU for an adult. Until November 2010 it was 2000 IU.
Well, let's be glad they have taken a step in the right direction, but remember, they can just as easily be wrong now as they have been for the last 13 years!
To put this upper limit in perspective, in 20 minutes on the beach an average fair-skinned adult can make at least 10,000 IU of vitamin D. (Dark-skinned people take longer, but make the same amount in the end.)
In fact, many people can make 20,000 IU of vitamin D in a single sunny session, five times as much as the IOM's Tolerable Upper Intake Level.
But perhaps nature has made a mistake, allowing us all that vitamin D? Thank heavens for the IOM!
Seriously, there is no record of anyone, anywhere, ever becoming vitamin D toxic from sunshine alone. So we can be pretty sure that even 20,000 IU of vitamin D3 daily is not toxic for a healthy adult.
In the light of modern research, widespread vitamin D deficiency and epidemic levels of vitamin D-related diseases, an upper limit for vitamin D of just 4000 IU is simply much too low.
Firstly, it does not allow for the rapid restoration of healthy vitamin D levels in people who are seriously deficient. At the end of winter that includes most of us. Secondly, many people cannot maintain even an adequate vitamin D blood level (35 ng/ml) on such a dose.
In any case, the concept of an upper daily limit for vitamin D is also somewhat flawed. Toxicity only occurs when a very large total quantity of vitamin D has been taken into the body (usually millions of International Units), in excess of the body's requirement.
Up until that point, very high daily doses of vitamin D3 (e.g. 50,000 IU) carry little risk for people in good health, even though repeated daily for several weeks. (This is not a dosage recommendation!)
You wouldn't think so. Vitamin D3 is a very inexpensive supplement. There's no money in it.
But cancer, heart disease and diabetes are all associated with vitamin D deficiency, together with dozens of other major and minor health challenges. The pharmaceutical and healthcare industries make billions of dollars from treating these diseases. Their profits will remain high as long as people remain vitamin D deficient. You can see where I am going with this.
Shouldn't the government protect us from corporate greed? They should, but perhaps they don't want to. Governments get huge tax revenues (and political parties receive campaign contributions) from wealthy pharmaceutical corporations. So why would governments (or even the opposition) want to jeopardise those funds?
And governments, despite what we would like to believe, do not wish for the people they serve to live longer. Governments' interests are best served when you work longer, but die sooner! (Especially if you voted for the opposition!)
So whose interests are being served by the IOM's new vitamin D RDA pronouncement? Not yours, gentle reader.
Although the IOM has failed to show the way, the more enlightened medical professionals, and some of the media are putting together the whole vitamin D story, and catching on to vitamin D's full potential.
I am sure the IOM will get there eventually. But you may not want to wait for them. They've only increased their recommended intake by 400 IU in the last 13 years. At this rate it would take them 143 more years to reach 5000 IU (an effective dose for many adults).
In the meanwhile, none of us is getting any younger.
You need to decide for yourself about vitamin D supplementation. It is critically important for your health. And you will want your decision to be well-informed, and based on sound science.
So if you can afford to invest a few minutes more, see vitamin D levels.