Widely fluctuating levels of Vitamin D may be harmful
Widely fluctuating levels of Vitamin D, due to summer sun exposure and winter sunlight deprivation, may be harmful.
From John Cannell, MD
http://www.vitamindcouncil.org/
Professor Reinhold Vieth of the University of Toronto, has produced evidence that widely fluctuating levels of Vitamin D in patients with low baseline 25(OH)D levels may increase the risk of prostate and pancreatic cancer. At least two prostate cancer studies and two pancreatic cancer studies show that higher baseline 25(OH)D levels at latitudes far from the equator increase, not decrease, the risk of these two malignancies. Vieth produces evidence that this increased risk is related to widely fluctuating levels 25(OH)D in those who rely on summer sun exposure for their Vitamin D.
The latency of the intracellular enzymes that activate and destroy vitamin D explains why Vitamin D should be obtained on a regular basis and not in periodic high doses. When 25(OH)D levels fall abruptly, like in the autumn in countries far from the equator, the enzyme that makes activated Vitamin D inside the cell is still set on low and the enzyme that destroys activated Vitamin D is still set on high and it takes several weeks or even months to fully reset. Vieth believes any supplementation strategy that uses large doses at longer than two month intervals should be avoided. However, high or Stoss doses, such as 50,000 IU of D3 every week or two should pose no problem. Vitamin D2, or ergocalciferol (Drisdol) should be avoided as it causes wider 25(OH)D fluctuations than D3 does.
posted by Dr. Joe @ 10/17/2009 09:58:00 AM
7 comments
7 Comments:
''Vieth believes any supplementation strategy that uses large doses at longer than two month intervals should be avoided.''
I've been using 50,000 IU a day for almost two years on your advice, Dr Joe. Thoughts?
P.S. I'm stopping all D3 intake immediately as a matter of urgency.
How to Optimize Vitamin D Supplementation to Prevent Cancer, Based on Cellular Adaptation and Hydroxylase Enzymology
Dr Vieth very kindly sent me a pre-publication, non copyright draft version of his paper. I've uploaded the full text to the above link.
The key point is that 25(OH)D level, ideally, needs to be kept high and stable.
I think it's worth making the effort to read the full text.
The diagrams alone make it much easier to grasp the idea that a sudden change in vitamin D status can create an imbalance in the ratio of 1-hydroxylase/24-hydroxylase.
Living at latitude 52 I've several friends who enjoy winter tropical sun breaks. I've noticed the sudden rise in Vitamin D status over a short winter sun holiday break appears to leave people vulnerable to catching infections on the return flight when breathing other peoples germs in the aircraft cabin is unavoidable.
Perhaps longer winter breaks, 3 weeks minimum, would be long enough to allow fine tuning to occur before the return flight home.
Another strategy maybe to raise 25(OH)D status a couple of months before you depart for your Winter break. Rely only on sun exposure while you are away, restart supplements the day before the return flight home. So there is less of a sudden or large change at any point.
Of course people who have been following Dr Joe's advice will be above the vulnerable zone and will not find going South for the Winter causes such a large or sudden change in vitamin D status.
The average UK reader has a 25(OH)D between 30nmol/l and 75nmol 12ng/ml~30ng/ml at these low levels, a greater faster rise in 25(OH)D occurs when given full body sun exposure.
Someone who has been following Dr Joe's advice will be starting their wintersun break with a level above 150 nmol/l or 60ng/ml and will be above the vulnerable zone.
When your body is fully charged with vitamin D it simply doesn't make as much vitamin D when given unlimited extra sun exposure.
It is vitamin D starved bodies that make the most vitamin D when fully exposed to sunlight. So it's these people who experience a greater rise in vitamin D level and a longer period of disregulation of the proliferative and anti-proliferative forces.
So does this mean we shouldn't use 50,000 IU (capsule form) on a daily basis as we've understood your recommendations in the past??? Thanks!
I think we need an answer to Linda's question...
Dr. Joe, I am also interested in your response to Linda's question above. I am still taking the 50,000 IUs you prescribed for me for the last 3 years. Is 50,000 IUs daily for many months dangerous???
Anyone who is worried about their current 25(OH)D status can easily arrange a postal vitamin D test from Grassrootshealth D Action
There is an interesting paper on the safety of Vitamin D from Vieth here
From diagram A you can see adverse events have only been recorded at levels ABOVE 500nmol/l = 200ng/ml and intakes ABOVE 50,000iu/daily.
However, to put that into perspective, I can also show you this link to a case where a woman was taking 150,000iu/d, three times the amount Dr Joe has suggested, for 28yrs without problem, and she was using D2 the form with a less safe track record.
While I personally haven't found any benefit from keeping my 25(OH)D above 100ng/ml I am aware of others with chronic conditions who find taking 50,000iu/daily helpful.
The point Vieth makes the first paper I linked to is that any sudden change in level (either up or down) is potentially harmful, as it allows a period of imbalance between the pro and anti proliferative controls.
Those people regularly taking large amounts of D3 daily will not experience ANY change in status as their level will always be at the maximum their body stabilizes.
In my opinion the very last thing anyone should do is to stop taking D3 suddenly.
If you decide you want to reduce your 25(OH)D level then doing so over a period of months by gradually extending the number of days between intakes would be better than stopping altogether immediately.
What matters is your body's individual response to D3. You will only know how it responds by taking a effective amount for an extended period and measuring the result.
If I had cancer I would rather have a level nearer 100ng/ml than below 50ng/ml and I would take as much D3 as required to stay at the upper end of the preferred range for cancer therapy 65~90ng/ml.
There is a new analogue of D3 being trialled as an aid to cancer therapy claimed to be TEN TIMES more potent than D3, so we can assume doctors would not be trying this out if they really thought, in practice, the current strength of D3 available, was adequate.
Dr. Joe, are you available to answer the question(s) above?
We would all appreciate your response.
Thanks!
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