A new randomized clinical trial finally puts to bed the question of whether taking large doses of Vitamin D has any benefit in the incidence or progression of prostate cancer. At least with over 3 years of follow up, it did not.
They previously proved it has no effect on cardiovascular risk. Other studies have failed to show a benefit in bone mineral density among people at risk for osteoporosis (Men on ADT and post-menopausal women).
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Tall_Allen
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"Vitamin D3 was initially given as one 100,000 iu pill, followed by 200,000 iu monthly pills"
That seems like some pretty unnatural dosing.
Not in the same league as moderate dialy dosing off someone with low levels of vitamin D.
But it is still cautionary about taking things to extremes without good evidence. There are probably lots of instances where a lot of a good thing is not helpful or is even counterproductive.
Thanks Tall for the data. What hit me the most in the study was this: "It should be remembered that Vitamin D is a steroidal hormone (like testosterone, estrogen, progesterone, and cortisol) and there are receptors for it on virtually all cells, healthy and cancerous."
my oncologist (finally) has made a dietary/supplement recommendation other than "nothing"....and that was to take a Calcium with D3 supplement. **I just checked and my calcium on latest tests is in very good normal range. I'm assuming the lower dose that I am taking could perhaps be beneficial? They did note a new spot on my pelvic bone area...and are putting me on Xgeva also....?
My GP recommends 50% of daily requirements come from a calcium citrate supplement for my osteopenia. So, what source is there to support my bone deficiency? I have met to the bone. Thank you.
I think canned salmon, herring, anchovies, etc. is the best source of dietary calcium because it has little bones that are made of the same mineral (apatite) that our bones are made of. Did you discuss using a bisphosphonate or using an estrogen patch (with tamoxifen)?
Why would you take ANY drug (whether available OTC or by Rx) that has neither been proven to be safe or effective? He should have his plasma levels of Vitamin D checked. If below 20 ng/ml, he can supplement, otherwise he is fine without it.
Only taking because it tested low and was prescribed. If I recall, Vit D was all the rage at the time but we will request a blood test next visit. Meanwhile, I pulled it.
A bit off subject but he also takes daily (all prescribed) baby aspirin, B12 1500, carotene complex which is Vit A 3000 mcg with 6 mg food carotenoids blend.
It's hard to argue against baby aspirin. As for the others - what is he taking them for? If he has a deficiency, it might make sense.
The CARET trial found that increased intake of beta-carotene and Vitamin A among people at high risk for lung cancer actually INCREASED the risk of lung cancer by 28%, increased the risk of death by 17%, and had a higher risk of cardiovascular disease mortality.
As with the SELECT trial on Vitamin E and Selenium, we learned that observational studies cannot be relied upon, and that cancer biochemistry is much more complex than we thought.
You are aware that the study you cited was in post-menopausal women and had nothing to do with prostate cancer? Here's what the authors say about that study:
"Participants received vitamin D alone rather than with
calcium. It is possible that both medications, acting separately
or synergistically, had a greater influence than vitamin
D alone, although a reduction in cancer incidence was not seen
in theWomen’s Health Initiative which also gave both supplements.
"The cancer profile in the ViDA study had a much
larger proportion of cases with melanoma (33%) (Table 2)
compared with the Nebraska study (6%), although analyses
restricted to nonskin cancer produced a similar null result.
Although I didn't have PC symptoms I did have chronic D deficiency noticed for two years prior to diagnosis. After the DX started taking 5,000 IU daily for three months and it brought level back to the norm. After that reduced it to 2,000 IU by the mineral metabolism specialist recommendation to support calcium absorption. I've never thought anyone would take it in hundred thousands IUs though...
100,000 IU per month is equivalent to a daily average of 3,333 IU per day. Vitamin D is stored in fat and the liver. The researchers wanted to give enough to have a significant impact on blood levels, and it did.
There is no evidence that Vitamin D is more greatly absorbed with a high fat meal. In fact, absorption is better with a low fat meal. But absorption rates do not affect the plasma vitamin D levels:
It is STORED in fat and the liver so a big dose stays in the body for use as needed. That's why it doesn't matter if you take a bigger dose less frequently or a smaller dose more frequently. They felt that they would get better compliance with 1 pill per month, and they did. They randomly did blood tests on men in the study and found that serum Vitamin D blood levels consistently increased by at least 20 ng/ml.
I find this article of questionable value. First the high/infrequent doses, second there seems to be no baseline data on participants' Vit d (and calcium) levels, and third, it's in New Zealand which is at best a temperate climate (I would be more apt to call it almost sub-tropical) where Vit d deficiency is not expected.
I discussed their rationale for high/infrequent doses above - it really should not matter for Vitamin D, but if you believe it does, you are free to ignore the evidence. The baseline mean serum Vitamin D was 25.5 ng/ml in the treatment group and 25.2 ng/ml in the control group. The baseline mean serum calcium was 9.2 mg/dl in both groups. So it was very similar to US levels for this age group.
Please look into taking vitamin K2 with D3 otherwise the calcium will go to the arteries and not the bones where you need it. My naturapath suggested it. I asked my pharmacist or never heard of K2. She called me the next day and said after googling there have been reputable studies verifying the goodness in adding K2 to my D3. I also take calcium. My prostate c spread to rib bone I take lupron and xgeva. since April. Psa of 11,000 now .4
I was given similar instructions from my urologist. He said the calcium was for bone metastasis. My vitamin D level was a bit low and wanted to raise it.
In fact, several OBSERVATIONAL studies showed an association (see the first paragraph of my blog). Countering that, several observational studies showed a negative effect on survival, for example:
That's why we do RANDOMIZED clinical trials (RCT) - to find out once and for all exactly what the relationship is. This RCT proved there is no relationship.
You would have to understand "levels of evidence," which all doctors, professional orgs, and medical journals subscribe to. I encourage you to learn about it. A well-done RCT like this one settles the question and trumps all previous observational studies.
If you understood levels of evidence, you could not make such a statement. It directly contradicts it. The "scientific community" has now proven no benefit beyond a doubt. You are free to follow your hunches, but the evidence does not support you.
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